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   <section id="reading-and-writing-data">
 <span id="arrow-io"></span><h1><a class="toc-backref" href="#id5" role="doc-backlink">Reading and writing data</a><a class="headerlink" href="#reading-and-writing-data" title="Link to this heading">¶</a></h1>
 <p>The <a class="reference external" href="https://arrow.apache.org/docs/java/ipc.html">Arrow IPC format</a> defines two types of binary formats
 for serializing Arrow data: the streaming format and the file format (or random access format). Such files can
 be directly memory-mapped when read.</p>
 <nav class="contents" id="contents">
 <p class="topic-title">Contents</p>
 <ul class="simple">
 <li><p><a class="reference internal" href="#reading-and-writing-data" id="id5">Reading and writing data</a></p>
 <ul>
 <li><p><a class="reference internal" href="#writing" id="id6">Writing</a></p>
 <ul>
 <li><p><a class="reference internal" href="#writing-random-access-files" id="id7">Writing Random Access Files</a></p>
 <ul>
 <li><p><a class="reference internal" href="#write-out-to-file" id="id8">Write - Out to File</a></p></li>
 <li><p><a class="reference internal" href="#write-out-to-buffer" id="id9">Write - Out to Buffer</a></p></li>
 </ul>
 </li>
 <li><p><a class="reference internal" href="#writing-streaming-format" id="id10">Writing Streaming Format</a></p>
 <ul>
 <li><p><a class="reference internal" href="#id1" id="id11">Write - Out to File</a></p></li>
 <li><p><a class="reference internal" href="#id2" id="id12">Write - Out to Buffer</a></p></li>
 </ul>
 </li>
 </ul>
 </li>
 <li><p><a class="reference internal" href="#reading" id="id13">Reading</a></p>
 <ul>
 <li><p><a class="reference internal" href="#reading-random-access-files" id="id14">Reading Random Access Files</a></p>
 <ul>
 <li><p><a class="reference internal" href="#read-from-file" id="id15">Read - From File</a></p></li>
 <li><p><a class="reference internal" href="#read-from-buffer" id="id16">Read - From Buffer</a></p></li>
 </ul>
 </li>
 <li><p><a class="reference internal" href="#reading-streaming-format" id="id17">Reading Streaming Format</a></p>
 <ul>
 <li><p><a class="reference internal" href="#id3" id="id18">Read - From File</a></p></li>
 <li><p><a class="reference internal" href="#id4" id="id19">Read - From Buffer</a></p></li>
 </ul>
 </li>
 <li><p><a class="reference internal" href="#reading-parquet-file" id="id20">Reading Parquet File</a></p></li>
 <li><p><a class="reference internal" href="#handling-data-with-dictionaries" id="id21">Handling Data with Dictionaries</a></p></li>
 </ul>
 </li>
 </ul>
 </li>
 </ul>
 </nav>
 <section id="writing">
 <h2><a class="toc-backref" href="#id6" role="doc-backlink">Writing</a><a class="headerlink" href="#writing" title="Link to this heading">¶</a></h2>
 <p>Both writing file and streaming formats use the same API.</p>
 <section id="writing-random-access-files">
 <h3><a class="toc-backref" href="#id7" role="doc-backlink">Writing Random Access Files</a><a class="headerlink" href="#writing-random-access-files" title="Link to this heading">¶</a></h3>
 <section id="write-out-to-file">
 <h4><a class="toc-backref" href="#id8" role="doc-backlink">Write - Out to File</a><a class="headerlink" href="#write-out-to-file" title="Link to this heading">¶</a></h4>
 <div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.BufferAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.RootAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VarCharVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.IntVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.Field</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.FieldType</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.ArrowType</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.Schema</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VectorSchemaRoot</span><span class="p">;</span>
 <span class="kn">import static</span><span class="w"> </span><span class="nn">java.util.Arrays.asList</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.ArrowFileWriter</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.File</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.FileOutputStream</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>

 <span class="k">try</span><span class="w"> </span><span class="p">(</span><span class="n">BufferAllocator</span><span class="w"> </span><span class="n">allocator</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RootAllocator</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="n">Field</span><span class="w"> </span><span class="n">name</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Field</span><span class="p">(</span><span class="s">&quot;name&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">FieldType</span><span class="p">.</span><span class="na">nullable</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">ArrowType</span><span class="p">.</span><span class="na">Utf8</span><span class="p">()),</span><span class="w"> </span><span class="kc">null</span><span class="p">);</span>
 <span class="w">    </span><span class="n">Field</span><span class="w"> </span><span class="n">age</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Field</span><span class="p">(</span><span class="s">&quot;age&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">FieldType</span><span class="p">.</span><span class="na">nullable</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">ArrowType</span><span class="p">.</span><span class="na">Int</span><span class="p">(</span><span class="mi">32</span><span class="p">,</span><span class="w"> </span><span class="kc">true</span><span class="p">)),</span><span class="w"> </span><span class="kc">null</span><span class="p">);</span>
 <span class="w">    </span><span class="n">Schema</span><span class="w"> </span><span class="n">schemaPerson</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Schema</span><span class="p">(</span><span class="n">asList</span><span class="p">(</span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="n">age</span><span class="p">));</span>
 <span class="w">    </span><span class="k">try</span><span class="p">(</span>
 <span class="w">        </span><span class="n">VectorSchemaRoot</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">VectorSchemaRoot</span><span class="p">.</span><span class="na">create</span><span class="p">(</span><span class="n">schemaPerson</span><span class="p">,</span><span class="w"> </span><span class="n">allocator</span><span class="p">)</span>
 <span class="w">    </span><span class="p">){</span>
 <span class="w">        </span><span class="n">VarCharVector</span><span class="w"> </span><span class="n">nameVector</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="n">VarCharVector</span><span class="p">)</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getVector</span><span class="p">(</span><span class="s">&quot;name&quot;</span><span class="p">);</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">allocateNew</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;David&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Gladis&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Juan&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">IntVector</span><span class="w"> </span><span class="n">ageVector</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="n">IntVector</span><span class="p">)</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getVector</span><span class="p">(</span><span class="s">&quot;age&quot;</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">allocateNew</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">20</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">30</span><span class="p">);</span>
 <span class="w">        </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">setRowCount</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="n">File</span><span class="w"> </span><span class="n">file</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">File</span><span class="p">(</span><span class="s">&quot;randon_access_to_file.arrow&quot;</span><span class="p">);</span>
 <span class="w">        </span><span class="k">try</span><span class="w"> </span><span class="p">(</span>
 <span class="w">            </span><span class="n">FileOutputStream</span><span class="w"> </span><span class="n">fileOutputStream</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">FileOutputStream</span><span class="p">(</span><span class="n">file</span><span class="p">);</span>
 <span class="w">            </span><span class="n">ArrowFileWriter</span><span class="w"> </span><span class="n">writer</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowFileWriter</span><span class="p">(</span><span class="n">vectorSchemaRoot</span><span class="p">,</span><span class="w"> </span><span class="kc">null</span><span class="p">,</span><span class="w"> </span><span class="n">fileOutputStream</span><span class="p">.</span><span class="na">getChannel</span><span class="p">())</span>
 <span class="w">        </span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">            </span><span class="n">writer</span><span class="p">.</span><span class="na">start</span><span class="p">();</span>
 <span class="w">            </span><span class="n">writer</span><span class="p">.</span><span class="na">writeBatch</span><span class="p">();</span>
 <span class="w">            </span><span class="n">writer</span><span class="p">.</span><span class="na">end</span><span class="p">();</span>
 <span class="w">            </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Record batches written: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">writer</span><span class="p">.</span><span class="na">getRecordBlocks</span><span class="p">().</span><span class="na">size</span><span class="p">()</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="s">&quot;. Number of rows written: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getRowCount</span><span class="p">());</span>
 <span class="w">        </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">            </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
 <span class="w">        </span><span class="p">}</span>
 <span class="w">    </span><span class="p">}</span>
 <span class="p">}</span>
 </pre></div>
 </div>
 <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Record batches written: 1. Number of rows written: 3
 </pre></div>
 </div>
 </section>
 <section id="write-out-to-buffer">
 <h4><a class="toc-backref" href="#id9" role="doc-backlink">Write - Out to Buffer</a><a class="headerlink" href="#write-out-to-buffer" title="Link to this heading">¶</a></h4>
 <div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.BufferAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.RootAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VarCharVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.IntVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.Field</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.FieldType</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.ArrowType</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.Schema</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VectorSchemaRoot</span><span class="p">;</span>
 <span class="kn">import static</span><span class="w"> </span><span class="nn">java.util.Arrays.asList</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.ArrowFileWriter</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.ByteArrayOutputStream</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.nio.channels.Channels</span><span class="p">;</span>

 <span class="k">try</span><span class="w"> </span><span class="p">(</span><span class="n">BufferAllocator</span><span class="w"> </span><span class="n">allocator</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RootAllocator</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="n">Field</span><span class="w"> </span><span class="n">name</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Field</span><span class="p">(</span><span class="s">&quot;name&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">FieldType</span><span class="p">.</span><span class="na">nullable</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">ArrowType</span><span class="p">.</span><span class="na">Utf8</span><span class="p">()),</span><span class="w"> </span><span class="kc">null</span><span class="p">);</span>
 <span class="w">    </span><span class="n">Field</span><span class="w"> </span><span class="n">age</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Field</span><span class="p">(</span><span class="s">&quot;age&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">FieldType</span><span class="p">.</span><span class="na">nullable</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">ArrowType</span><span class="p">.</span><span class="na">Int</span><span class="p">(</span><span class="mi">32</span><span class="p">,</span><span class="w"> </span><span class="kc">true</span><span class="p">)),</span><span class="w"> </span><span class="kc">null</span><span class="p">);</span>
 <span class="w">    </span><span class="n">Schema</span><span class="w"> </span><span class="n">schemaPerson</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Schema</span><span class="p">(</span><span class="n">asList</span><span class="p">(</span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="n">age</span><span class="p">));</span>
 <span class="w">    </span><span class="k">try</span><span class="p">(</span>
 <span class="w">        </span><span class="n">VectorSchemaRoot</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">VectorSchemaRoot</span><span class="p">.</span><span class="na">create</span><span class="p">(</span><span class="n">schemaPerson</span><span class="p">,</span><span class="w"> </span><span class="n">allocator</span><span class="p">)</span>
 <span class="w">    </span><span class="p">){</span>
 <span class="w">        </span><span class="n">VarCharVector</span><span class="w"> </span><span class="n">nameVector</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="n">VarCharVector</span><span class="p">)</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getVector</span><span class="p">(</span><span class="s">&quot;name&quot;</span><span class="p">);</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">allocateNew</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;David&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Gladis&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Juan&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">IntVector</span><span class="w"> </span><span class="n">ageVector</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="n">IntVector</span><span class="p">)</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getVector</span><span class="p">(</span><span class="s">&quot;age&quot;</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">allocateNew</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">20</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">30</span><span class="p">);</span>
 <span class="w">        </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">setRowCount</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="k">try</span><span class="w"> </span><span class="p">(</span>
 <span class="w">            </span><span class="n">ByteArrayOutputStream</span><span class="w"> </span><span class="n">out</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ByteArrayOutputStream</span><span class="p">();</span>
 <span class="w">             </span><span class="n">ArrowFileWriter</span><span class="w"> </span><span class="n">writer</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowFileWriter</span><span class="p">(</span><span class="n">vectorSchemaRoot</span><span class="p">,</span><span class="w"> </span><span class="kc">null</span><span class="p">,</span><span class="w"> </span><span class="n">Channels</span><span class="p">.</span><span class="na">newChannel</span><span class="p">(</span><span class="n">out</span><span class="p">))</span>
 <span class="w">        </span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">            </span><span class="n">writer</span><span class="p">.</span><span class="na">start</span><span class="p">();</span>
 <span class="w">            </span><span class="n">writer</span><span class="p">.</span><span class="na">writeBatch</span><span class="p">();</span>

 <span class="w">            </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Record batches written: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">writer</span><span class="p">.</span><span class="na">getRecordBlocks</span><span class="p">().</span><span class="na">size</span><span class="p">()</span><span class="w"> </span><span class="o">+</span>
 <span class="w">                    </span><span class="s">&quot;. Number of rows written: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getRowCount</span><span class="p">());</span>
 <span class="w">        </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">            </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
 <span class="w">        </span><span class="p">}</span>
 <span class="w">    </span><span class="p">}</span>
 <span class="p">}</span>
 </pre></div>
 </div>
 <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Record batches written: 1. Number of rows written: 3
 </pre></div>
 </div>
 </section>
 </section>
 <section id="writing-streaming-format">
 <h3><a class="toc-backref" href="#id10" role="doc-backlink">Writing Streaming Format</a><a class="headerlink" href="#writing-streaming-format" title="Link to this heading">¶</a></h3>
 <section id="id1">
 <h4><a class="toc-backref" href="#id11" role="doc-backlink">Write - Out to File</a><a class="headerlink" href="#id1" title="Link to this heading">¶</a></h4>
 <div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.BufferAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.RootAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VarCharVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.IntVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.ArrowStreamWriter</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.Field</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.FieldType</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.ArrowType</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.Schema</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VectorSchemaRoot</span><span class="p">;</span>
 <span class="kn">import static</span><span class="w"> </span><span class="nn">java.util.Arrays.asList</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.File</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.FileOutputStream</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>

 <span class="k">try</span><span class="w"> </span><span class="p">(</span><span class="n">BufferAllocator</span><span class="w"> </span><span class="n">rootAllocator</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RootAllocator</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="n">Field</span><span class="w"> </span><span class="n">name</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Field</span><span class="p">(</span><span class="s">&quot;name&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">FieldType</span><span class="p">.</span><span class="na">nullable</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">ArrowType</span><span class="p">.</span><span class="na">Utf8</span><span class="p">()),</span><span class="w"> </span><span class="kc">null</span><span class="p">);</span>
 <span class="w">    </span><span class="n">Field</span><span class="w"> </span><span class="n">age</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Field</span><span class="p">(</span><span class="s">&quot;age&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">FieldType</span><span class="p">.</span><span class="na">nullable</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">ArrowType</span><span class="p">.</span><span class="na">Int</span><span class="p">(</span><span class="mi">32</span><span class="p">,</span><span class="w"> </span><span class="kc">true</span><span class="p">)),</span><span class="w"> </span><span class="kc">null</span><span class="p">);</span>
 <span class="w">    </span><span class="n">Schema</span><span class="w"> </span><span class="n">schemaPerson</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Schema</span><span class="p">(</span><span class="n">asList</span><span class="p">(</span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="n">age</span><span class="p">));</span>
 <span class="w">    </span><span class="k">try</span><span class="p">(</span>
 <span class="w">        </span><span class="n">VectorSchemaRoot</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">VectorSchemaRoot</span><span class="p">.</span><span class="na">create</span><span class="p">(</span><span class="n">schemaPerson</span><span class="p">,</span><span class="w"> </span><span class="n">rootAllocator</span><span class="p">)</span>
 <span class="w">    </span><span class="p">){</span>
 <span class="w">        </span><span class="n">VarCharVector</span><span class="w"> </span><span class="n">nameVector</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="n">VarCharVector</span><span class="p">)</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getVector</span><span class="p">(</span><span class="s">&quot;name&quot;</span><span class="p">);</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">allocateNew</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;David&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Gladis&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Juan&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">IntVector</span><span class="w"> </span><span class="n">ageVector</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="n">IntVector</span><span class="p">)</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getVector</span><span class="p">(</span><span class="s">&quot;age&quot;</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">allocateNew</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">20</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">30</span><span class="p">);</span>
 <span class="w">        </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">setRowCount</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="n">File</span><span class="w"> </span><span class="n">file</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">File</span><span class="p">(</span><span class="s">&quot;streaming_to_file.arrow&quot;</span><span class="p">);</span>
 <span class="w">        </span><span class="k">try</span><span class="w"> </span><span class="p">(</span>
 <span class="w">            </span><span class="n">FileOutputStream</span><span class="w"> </span><span class="n">fileOutputStream</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">FileOutputStream</span><span class="p">(</span><span class="n">file</span><span class="p">);</span>
 <span class="w">            </span><span class="n">ArrowStreamWriter</span><span class="w"> </span><span class="n">writer</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowStreamWriter</span><span class="p">(</span><span class="n">vectorSchemaRoot</span><span class="p">,</span><span class="w"> </span><span class="kc">null</span><span class="p">,</span><span class="w"> </span><span class="n">fileOutputStream</span><span class="p">.</span><span class="na">getChannel</span><span class="p">())</span>
 <span class="w">        </span><span class="p">){</span>
 <span class="w">            </span><span class="n">writer</span><span class="p">.</span><span class="na">start</span><span class="p">();</span>
 <span class="w">            </span><span class="n">writer</span><span class="p">.</span><span class="na">writeBatch</span><span class="p">();</span>
 <span class="w">            </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Number of rows written: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getRowCount</span><span class="p">());</span>
 <span class="w">        </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">            </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
 <span class="w">        </span><span class="p">}</span>
 <span class="w">    </span><span class="p">}</span>
 <span class="p">}</span>
 </pre></div>
 </div>
 <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Number of rows written: 3
 </pre></div>
 </div>
 </section>
 <section id="id2">
 <h4><a class="toc-backref" href="#id12" role="doc-backlink">Write - Out to Buffer</a><a class="headerlink" href="#id2" title="Link to this heading">¶</a></h4>
 <div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.BufferAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.RootAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VarCharVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.IntVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.ArrowStreamWriter</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.Field</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.FieldType</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.ArrowType</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.Schema</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VectorSchemaRoot</span><span class="p">;</span>
 <span class="kn">import static</span><span class="w"> </span><span class="nn">java.util.Arrays.asList</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.ByteArrayOutputStream</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.nio.channels.Channels</span><span class="p">;</span>

 <span class="k">try</span><span class="w"> </span><span class="p">(</span><span class="n">BufferAllocator</span><span class="w"> </span><span class="n">rootAllocator</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RootAllocator</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="n">Field</span><span class="w"> </span><span class="n">name</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Field</span><span class="p">(</span><span class="s">&quot;name&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">FieldType</span><span class="p">.</span><span class="na">nullable</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">ArrowType</span><span class="p">.</span><span class="na">Utf8</span><span class="p">()),</span><span class="w"> </span><span class="kc">null</span><span class="p">);</span>
 <span class="w">    </span><span class="n">Field</span><span class="w"> </span><span class="n">age</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Field</span><span class="p">(</span><span class="s">&quot;age&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">FieldType</span><span class="p">.</span><span class="na">nullable</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">ArrowType</span><span class="p">.</span><span class="na">Int</span><span class="p">(</span><span class="mi">32</span><span class="p">,</span><span class="w"> </span><span class="kc">true</span><span class="p">)),</span><span class="w"> </span><span class="kc">null</span><span class="p">);</span>
 <span class="w">    </span><span class="n">Schema</span><span class="w"> </span><span class="n">schemaPerson</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Schema</span><span class="p">(</span><span class="n">asList</span><span class="p">(</span><span class="n">name</span><span class="p">,</span><span class="w"> </span><span class="n">age</span><span class="p">));</span>
 <span class="w">    </span><span class="k">try</span><span class="p">(</span>
 <span class="w">        </span><span class="n">VectorSchemaRoot</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">VectorSchemaRoot</span><span class="p">.</span><span class="na">create</span><span class="p">(</span><span class="n">schemaPerson</span><span class="p">,</span><span class="w"> </span><span class="n">rootAllocator</span><span class="p">)</span>
 <span class="w">    </span><span class="p">){</span>
 <span class="w">        </span><span class="n">VarCharVector</span><span class="w"> </span><span class="n">nameVector</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="n">VarCharVector</span><span class="p">)</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getVector</span><span class="p">(</span><span class="s">&quot;name&quot;</span><span class="p">);</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">allocateNew</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;David&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Gladis&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">nameVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Juan&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">());</span>
 <span class="w">        </span><span class="n">IntVector</span><span class="w"> </span><span class="n">ageVector</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="n">IntVector</span><span class="p">)</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getVector</span><span class="p">(</span><span class="s">&quot;age&quot;</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">allocateNew</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="mi">10</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">20</span><span class="p">);</span>
 <span class="w">        </span><span class="n">ageVector</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">30</span><span class="p">);</span>
 <span class="w">        </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">setRowCount</span><span class="p">(</span><span class="mi">3</span><span class="p">);</span>
 <span class="w">        </span><span class="k">try</span><span class="w"> </span><span class="p">(</span>
 <span class="w">            </span><span class="n">ByteArrayOutputStream</span><span class="w"> </span><span class="n">out</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ByteArrayOutputStream</span><span class="p">();</span>
 <span class="w">            </span><span class="n">ArrowStreamWriter</span><span class="w"> </span><span class="n">writer</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowStreamWriter</span><span class="p">(</span><span class="n">vectorSchemaRoot</span><span class="p">,</span><span class="w"> </span><span class="kc">null</span><span class="p">,</span><span class="w"> </span><span class="n">Channels</span><span class="p">.</span><span class="na">newChannel</span><span class="p">(</span><span class="n">out</span><span class="p">))</span>
 <span class="w">        </span><span class="p">){</span>
 <span class="w">            </span><span class="n">writer</span><span class="p">.</span><span class="na">start</span><span class="p">();</span>
 <span class="w">            </span><span class="n">writer</span><span class="p">.</span><span class="na">writeBatch</span><span class="p">();</span>
 <span class="w">            </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Number of rows written: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getRowCount</span><span class="p">());</span>
 <span class="w">        </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">            </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
 <span class="w">        </span><span class="p">}</span>
 <span class="w">    </span><span class="p">}</span>
 <span class="p">}</span>
 </pre></div>
 </div>
 <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Number of rows written: 3
 </pre></div>
 </div>
 </section>
 </section>
 </section>
 <section id="reading">
 <h2><a class="toc-backref" href="#id13" role="doc-backlink">Reading</a><a class="headerlink" href="#reading" title="Link to this heading">¶</a></h2>
 <p>Reading the random access format and streaming format both offer the same API,
 with the difference that random access files also offer access to any record batch by index.</p>
 <section id="reading-random-access-files">
 <h3><a class="toc-backref" href="#id14" role="doc-backlink">Reading Random Access Files</a><a class="headerlink" href="#reading-random-access-files" title="Link to this heading">¶</a></h3>
 <section id="read-from-file">
 <h4><a class="toc-backref" href="#id15" role="doc-backlink">Read - From File</a><a class="headerlink" href="#read-from-file" title="Link to this heading">¶</a></h4>
 <p>We are providing a path with auto generated arrow files for testing purposes, change that at your convenience.</p>
 <div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.BufferAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.RootAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.ArrowFileReader</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.message.ArrowBlock</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VectorSchemaRoot</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.File</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.FileInputStream</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>

 <span class="n">File</span><span class="w"> </span><span class="n">file</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">File</span><span class="p">(</span><span class="s">&quot;./thirdpartydeps/arrowfiles/random_access.arrow&quot;</span><span class="p">);</span>
 <span class="k">try</span><span class="p">(</span>
 <span class="w">    </span><span class="n">BufferAllocator</span><span class="w"> </span><span class="n">rootAllocator</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RootAllocator</span><span class="p">();</span>
 <span class="w">    </span><span class="n">FileInputStream</span><span class="w"> </span><span class="n">fileInputStream</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">FileInputStream</span><span class="p">(</span><span class="n">file</span><span class="p">);</span>
 <span class="w">    </span><span class="n">ArrowFileReader</span><span class="w"> </span><span class="n">reader</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowFileReader</span><span class="p">(</span><span class="n">fileInputStream</span><span class="p">.</span><span class="na">getChannel</span><span class="p">(),</span><span class="w"> </span><span class="n">rootAllocator</span><span class="p">)</span>
 <span class="p">){</span>
 <span class="w">    </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Record batches in file: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">reader</span><span class="p">.</span><span class="na">getRecordBlocks</span><span class="p">().</span><span class="na">size</span><span class="p">());</span>
 <span class="w">    </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="n">ArrowBlock</span><span class="w"> </span><span class="n">arrowBlock</span><span class="w"> </span><span class="p">:</span><span class="w"> </span><span class="n">reader</span><span class="p">.</span><span class="na">getRecordBlocks</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
 <span class="w">        </span><span class="n">reader</span><span class="p">.</span><span class="na">loadRecordBatch</span><span class="p">(</span><span class="n">arrowBlock</span><span class="p">);</span>
 <span class="w">        </span><span class="n">VectorSchemaRoot</span><span class="w"> </span><span class="n">vectorSchemaRootRecover</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">reader</span><span class="p">.</span><span class="na">getVectorSchemaRoot</span><span class="p">();</span>
 <span class="w">        </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">print</span><span class="p">(</span><span class="n">vectorSchemaRootRecover</span><span class="p">.</span><span class="na">contentToTSVString</span><span class="p">());</span>
 <span class="w">    </span><span class="p">}</span>
 <span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
 <span class="p">}</span>
 </pre></div>
 </div>
 <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Record batches in file: 3
 name    age
 David    10
 Gladis    20
 Juan    30
 name    age
 Nidia    15
 Alexa    20
 Mara    15
 name    age
 Raul    34
 Jhon    29
 Thomy    33
 </pre></div>
 </div>
 </section>
 <section id="read-from-buffer">
 <h4><a class="toc-backref" href="#id16" role="doc-backlink">Read - From Buffer</a><a class="headerlink" href="#read-from-buffer" title="Link to this heading">¶</a></h4>
 <div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.BufferAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.RootAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.ArrowFileReader</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.SeekableReadChannel</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.message.ArrowBlock</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VectorSchemaRoot</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.util.ByteArrayReadableSeekableByteChannel</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.nio.file.Files</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.nio.file.Path</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.nio.file.Paths</span><span class="p">;</span>

 <span class="n">Path</span><span class="w"> </span><span class="n">path</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">Paths</span><span class="p">.</span><span class="na">get</span><span class="p">(</span><span class="s">&quot;./thirdpartydeps/arrowfiles/random_access.arrow&quot;</span><span class="p">);</span>
 <span class="k">try</span><span class="p">(</span>
 <span class="w">    </span><span class="n">BufferAllocator</span><span class="w"> </span><span class="n">rootAllocator</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RootAllocator</span><span class="p">();</span>
 <span class="w">    </span><span class="n">ArrowFileReader</span><span class="w"> </span><span class="n">reader</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowFileReader</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">SeekableReadChannel</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">ByteArrayReadableSeekableByteChannel</span><span class="p">(</span>
 <span class="w">                                        </span><span class="n">Files</span><span class="p">.</span><span class="na">readAllBytes</span><span class="p">(</span><span class="n">path</span><span class="p">))),</span><span class="w"> </span><span class="n">rootAllocator</span><span class="p">)</span>
 <span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Record batches in file: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">reader</span><span class="p">.</span><span class="na">getRecordBlocks</span><span class="p">().</span><span class="na">size</span><span class="p">());</span>
 <span class="w">    </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="n">ArrowBlock</span><span class="w"> </span><span class="n">arrowBlock</span><span class="w"> </span><span class="p">:</span><span class="w"> </span><span class="n">reader</span><span class="p">.</span><span class="na">getRecordBlocks</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
 <span class="w">        </span><span class="n">reader</span><span class="p">.</span><span class="na">loadRecordBatch</span><span class="p">(</span><span class="n">arrowBlock</span><span class="p">);</span>
 <span class="w">        </span><span class="n">VectorSchemaRoot</span><span class="w"> </span><span class="n">vectorSchemaRootRecover</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">reader</span><span class="p">.</span><span class="na">getVectorSchemaRoot</span><span class="p">();</span>
 <span class="w">        </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">print</span><span class="p">(</span><span class="n">vectorSchemaRootRecover</span><span class="p">.</span><span class="na">contentToTSVString</span><span class="p">());</span>
 <span class="w">    </span><span class="p">}</span>
 <span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
 <span class="p">}</span>
 </pre></div>
 </div>
 <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Record batches in file: 3
 name    age
 David    10
 Gladis    20
 Juan    30
 name    age
 Nidia    15
 Alexa    20
 Mara    15
 name    age
 Raul    34
 Jhon    29
 Thomy    33
 </pre></div>
 </div>
 </section>
 </section>
 <section id="reading-streaming-format">
 <h3><a class="toc-backref" href="#id17" role="doc-backlink">Reading Streaming Format</a><a class="headerlink" href="#reading-streaming-format" title="Link to this heading">¶</a></h3>
 <section id="id3">
 <h4><a class="toc-backref" href="#id18" role="doc-backlink">Read - From File</a><a class="headerlink" href="#id3" title="Link to this heading">¶</a></h4>
 <div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.BufferAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.RootAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.ArrowStreamReader</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VectorSchemaRoot</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.File</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.FileInputStream</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>

 <span class="n">File</span><span class="w"> </span><span class="n">file</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">File</span><span class="p">(</span><span class="s">&quot;./thirdpartydeps/arrowfiles/streaming.arrow&quot;</span><span class="p">);</span>
 <span class="k">try</span><span class="p">(</span>
 <span class="w">    </span><span class="n">BufferAllocator</span><span class="w"> </span><span class="n">rootAllocator</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RootAllocator</span><span class="p">();</span>
 <span class="w">    </span><span class="n">FileInputStream</span><span class="w"> </span><span class="n">fileInputStreamForStream</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">FileInputStream</span><span class="p">(</span><span class="n">file</span><span class="p">);</span>
 <span class="w">    </span><span class="n">ArrowStreamReader</span><span class="w"> </span><span class="n">reader</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowStreamReader</span><span class="p">(</span><span class="n">fileInputStreamForStream</span><span class="p">,</span><span class="w"> </span><span class="n">rootAllocator</span><span class="p">)</span>
 <span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="k">while</span><span class="w"> </span><span class="p">(</span><span class="n">reader</span><span class="p">.</span><span class="na">loadNextBatch</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
 <span class="w">        </span><span class="n">VectorSchemaRoot</span><span class="w"> </span><span class="n">vectorSchemaRootRecover</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">reader</span><span class="p">.</span><span class="na">getVectorSchemaRoot</span><span class="p">();</span>
 <span class="w">        </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">print</span><span class="p">(</span><span class="n">vectorSchemaRootRecover</span><span class="p">.</span><span class="na">contentToTSVString</span><span class="p">());</span>
 <span class="w">    </span><span class="p">}</span>
 <span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
 <span class="p">}</span>
 </pre></div>
 </div>
 <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>name    age
 David    10
 Gladis    20
 Juan    30
 name    age
 Nidia    15
 Alexa    20
 Mara    15
 name    age
 Raul    34
 Jhon    29
 Thomy    33
 </pre></div>
 </div>
 </section>
 <section id="id4">
 <h4><a class="toc-backref" href="#id19" role="doc-backlink">Read - From Buffer</a><a class="headerlink" href="#id4" title="Link to this heading">¶</a></h4>
 <div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.BufferAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.RootAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.ArrowStreamReader</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.ByteArrayInputStream</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.nio.file.Files</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.nio.file.Path</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.nio.file.Paths</span><span class="p">;</span>

 <span class="n">Path</span><span class="w"> </span><span class="n">path</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">Paths</span><span class="p">.</span><span class="na">get</span><span class="p">(</span><span class="s">&quot;./thirdpartydeps/arrowfiles/streaming.arrow&quot;</span><span class="p">);</span>
 <span class="k">try</span><span class="p">(</span>
 <span class="w">    </span><span class="n">BufferAllocator</span><span class="w"> </span><span class="n">rootAllocator</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RootAllocator</span><span class="p">();</span>
 <span class="w">    </span><span class="n">ArrowStreamReader</span><span class="w"> </span><span class="n">reader</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowStreamReader</span><span class="p">(</span><span class="k">new</span><span class="w"> </span><span class="n">ByteArrayInputStream</span><span class="p">(</span>
 <span class="w">                                    </span><span class="n">Files</span><span class="p">.</span><span class="na">readAllBytes</span><span class="p">(</span><span class="n">path</span><span class="p">)),</span><span class="w"> </span><span class="n">rootAllocator</span><span class="p">)</span>
 <span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="k">while</span><span class="p">(</span><span class="n">reader</span><span class="p">.</span><span class="na">loadNextBatch</span><span class="p">()){</span>
 <span class="w">        </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">print</span><span class="p">(</span><span class="n">reader</span><span class="p">.</span><span class="na">getVectorSchemaRoot</span><span class="p">().</span><span class="na">contentToTSVString</span><span class="p">());</span>
 <span class="w">    </span><span class="p">}</span>
 <span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
 <span class="p">}</span>
 </pre></div>
 </div>
 <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>name    age
 David    10
 Gladis    20
 Juan    30
 name    age
 Nidia    15
 Alexa    20
 Mara    15
 name    age
 Raul    34
 Jhon    29
 Thomy    33
 </pre></div>
 </div>
 </section>
 </section>
 <section id="reading-parquet-file">
 <h3><a class="toc-backref" href="#id20" role="doc-backlink">Reading Parquet File</a><a class="headerlink" href="#reading-parquet-file" title="Link to this heading">¶</a></h3>
 <p>Please check <a class="reference internal" href="dataset.html"><span class="doc">Dataset</span></a></p>
 </section>
 <section id="handling-data-with-dictionaries">
 <h3><a class="toc-backref" href="#id21" role="doc-backlink">Handling Data with Dictionaries</a><a class="headerlink" href="#handling-data-with-dictionaries" title="Link to this heading">¶</a></h3>
 <p>Reading and writing dictionary-encoded data requires separately tracking the dictionaries.</p>
 <div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.BufferAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.memory.RootAllocator</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.FieldVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ValueVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VarCharVector</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.VectorSchemaRoot</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.dictionary.Dictionary</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.dictionary.DictionaryEncoder</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.dictionary.DictionaryProvider</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.ArrowFileReader</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.ArrowFileWriter</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.ipc.message.ArrowBlock</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.Types</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.ArrowType</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.DictionaryEncoding</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">org.apache.arrow.vector.types.pojo.FieldType</span><span class="p">;</span>

 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.File</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.FileInputStream</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.FileNotFoundException</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.FileOutputStream</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>
 <span class="kn">import</span><span class="w"> </span><span class="nn">java.nio.charset.StandardCharsets</span><span class="p">;</span>

 <span class="n">DictionaryEncoding</span><span class="w"> </span><span class="n">dictionaryEncoding</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">DictionaryEncoding</span><span class="p">(</span>
 <span class="w">        </span><span class="cm">/*id=*/</span><span class="mi">666L</span><span class="p">,</span><span class="w"> </span><span class="cm">/*ordered=*/</span><span class="kc">false</span><span class="p">,</span><span class="w"> </span><span class="cm">/*indexType=*/</span>
 <span class="w">        </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowType</span><span class="p">.</span><span class="na">Int</span><span class="p">(</span><span class="mi">8</span><span class="p">,</span><span class="w"> </span><span class="kc">true</span><span class="p">)</span>
 <span class="p">);</span>
 <span class="k">try</span><span class="w"> </span><span class="p">(</span><span class="n">BufferAllocator</span><span class="w"> </span><span class="n">root</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RootAllocator</span><span class="p">();</span>
 <span class="w">     </span><span class="n">VarCharVector</span><span class="w"> </span><span class="n">countries</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">VarCharVector</span><span class="p">(</span><span class="s">&quot;country-dict&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">root</span><span class="p">);</span>
 <span class="w">     </span><span class="n">VarCharVector</span><span class="w"> </span><span class="n">appUserCountriesUnencoded</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">VarCharVector</span><span class="p">(</span>
 <span class="w">             </span><span class="s">&quot;app-use-country-dict&quot;</span><span class="p">,</span>
 <span class="w">             </span><span class="k">new</span><span class="w"> </span><span class="n">FieldType</span><span class="p">(</span><span class="kc">true</span><span class="p">,</span><span class="w"> </span><span class="n">Types</span><span class="p">.</span><span class="na">MinorType</span><span class="p">.</span><span class="na">VARCHAR</span><span class="p">.</span><span class="na">getType</span><span class="p">(),</span><span class="w"> </span><span class="n">dictionaryEncoding</span><span class="p">),</span>
 <span class="w">             </span><span class="n">root</span><span class="p">)</span>
 <span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">allocateNew</span><span class="p">(</span><span class="mi">10</span><span class="p">);</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Andorra&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Cuba&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Grecia&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Guinea&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Islandia&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Malta&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">6</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Tailandia&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">7</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Uganda&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">8</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Yemen&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">9</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Zambia&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">countries</span><span class="p">.</span><span class="na">setValueCount</span><span class="p">(</span><span class="mi">10</span><span class="p">);</span>

 <span class="w">    </span><span class="n">Dictionary</span><span class="w"> </span><span class="n">countriesDictionary</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">Dictionary</span><span class="p">(</span><span class="n">countries</span><span class="p">,</span><span class="w"> </span><span class="n">dictionaryEncoding</span><span class="p">);</span>
 <span class="w">    </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Dictionary: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">countriesDictionary</span><span class="p">);</span>

 <span class="w">    </span><span class="n">appUserCountriesUnencoded</span><span class="p">.</span><span class="na">allocateNew</span><span class="p">(</span><span class="mi">5</span><span class="p">);</span>
 <span class="w">    </span><span class="n">appUserCountriesUnencoded</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Andorra&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">appUserCountriesUnencoded</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Guinea&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">appUserCountriesUnencoded</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Islandia&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">appUserCountriesUnencoded</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Malta&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">appUserCountriesUnencoded</span><span class="p">.</span><span class="na">set</span><span class="p">(</span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Uganda&quot;</span><span class="p">.</span><span class="na">getBytes</span><span class="p">(</span><span class="n">StandardCharsets</span><span class="p">.</span><span class="na">UTF_8</span><span class="p">));</span>
 <span class="w">    </span><span class="n">appUserCountriesUnencoded</span><span class="p">.</span><span class="na">setValueCount</span><span class="p">(</span><span class="mi">5</span><span class="p">);</span>
 <span class="w">    </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Unencoded data: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">appUserCountriesUnencoded</span><span class="p">);</span>

 <span class="w">    </span><span class="n">File</span><span class="w"> </span><span class="n">file</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">File</span><span class="p">(</span><span class="s">&quot;random_access_file_with_dictionary.arrow&quot;</span><span class="p">);</span>
 <span class="w">    </span><span class="n">DictionaryProvider</span><span class="p">.</span><span class="na">MapDictionaryProvider</span><span class="w"> </span><span class="n">provider</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">DictionaryProvider</span><span class="p">.</span><span class="na">MapDictionaryProvider</span><span class="p">();</span>
 <span class="w">    </span><span class="n">provider</span><span class="p">.</span><span class="na">put</span><span class="p">(</span><span class="n">countriesDictionary</span><span class="p">);</span>
 <span class="w">    </span><span class="k">try</span><span class="w"> </span><span class="p">(</span><span class="n">FieldVector</span><span class="w"> </span><span class="n">appUseCountryDictionaryEncoded</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="n">FieldVector</span><span class="p">)</span><span class="w"> </span><span class="n">DictionaryEncoder</span>
 <span class="w">            </span><span class="p">.</span><span class="na">encode</span><span class="p">(</span><span class="n">appUserCountriesUnencoded</span><span class="p">,</span><span class="w"> </span><span class="n">countriesDictionary</span><span class="p">);</span>
 <span class="w">         </span><span class="n">VectorSchemaRoot</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">VectorSchemaRoot</span><span class="p">.</span><span class="na">of</span><span class="p">(</span><span class="n">appUseCountryDictionaryEncoded</span><span class="p">);</span>
 <span class="w">         </span><span class="n">FileOutputStream</span><span class="w"> </span><span class="n">fileOutputStream</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">FileOutputStream</span><span class="p">(</span><span class="n">file</span><span class="p">);</span>
 <span class="w">         </span><span class="n">ArrowFileWriter</span><span class="w"> </span><span class="n">writer</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowFileWriter</span><span class="p">(</span><span class="n">vectorSchemaRoot</span><span class="p">,</span><span class="w"> </span><span class="n">provider</span><span class="p">,</span><span class="w"> </span><span class="n">fileOutputStream</span><span class="p">.</span><span class="na">getChannel</span><span class="p">())</span>
 <span class="w">    </span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">        </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Dictionary-encoded data: &quot;</span><span class="w"> </span><span class="o">+</span><span class="n">appUseCountryDictionaryEncoded</span><span class="p">);</span>
 <span class="w">        </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Dictionary-encoded ID: &quot;</span><span class="w"> </span><span class="o">+</span><span class="n">appUseCountryDictionaryEncoded</span><span class="p">.</span><span class="na">getField</span><span class="p">().</span><span class="na">getDictionary</span><span class="p">().</span><span class="na">getId</span><span class="p">());</span>
 <span class="w">        </span><span class="n">writer</span><span class="p">.</span><span class="na">start</span><span class="p">();</span>
 <span class="w">        </span><span class="n">writer</span><span class="p">.</span><span class="na">writeBatch</span><span class="p">();</span>
 <span class="w">        </span><span class="n">writer</span><span class="p">.</span><span class="na">end</span><span class="p">();</span>
 <span class="w">        </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Record batches written: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">writer</span><span class="p">.</span><span class="na">getRecordBlocks</span><span class="p">().</span><span class="na">size</span><span class="p">()</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="s">&quot;. Number of rows written: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">vectorSchemaRoot</span><span class="p">.</span><span class="na">getRowCount</span><span class="p">());</span>
 <span class="w">        </span><span class="k">try</span><span class="p">(</span>
 <span class="w">            </span><span class="n">BufferAllocator</span><span class="w"> </span><span class="n">rootAllocator</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RootAllocator</span><span class="p">();</span>
 <span class="w">            </span><span class="n">FileInputStream</span><span class="w"> </span><span class="n">fileInputStream</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">FileInputStream</span><span class="p">(</span><span class="n">file</span><span class="p">);</span>
 <span class="w">            </span><span class="n">ArrowFileReader</span><span class="w"> </span><span class="n">reader</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ArrowFileReader</span><span class="p">(</span><span class="n">fileInputStream</span><span class="p">.</span><span class="na">getChannel</span><span class="p">(),</span><span class="w"> </span><span class="n">rootAllocator</span><span class="p">)</span>
 <span class="w">        </span><span class="p">){</span>
 <span class="w">            </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="n">ArrowBlock</span><span class="w"> </span><span class="n">arrowBlock</span><span class="w"> </span><span class="p">:</span><span class="w"> </span><span class="n">reader</span><span class="p">.</span><span class="na">getRecordBlocks</span><span class="p">())</span><span class="w"> </span><span class="p">{</span>
 <span class="w">                </span><span class="n">reader</span><span class="p">.</span><span class="na">loadRecordBatch</span><span class="p">(</span><span class="n">arrowBlock</span><span class="p">);</span>
 <span class="w">                </span><span class="n">FieldVector</span><span class="w"> </span><span class="n">appUseCountryDictionaryEncodedRead</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">reader</span><span class="p">.</span><span class="na">getVectorSchemaRoot</span><span class="p">().</span><span class="na">getVector</span><span class="p">(</span><span class="s">&quot;app-use-country-dict&quot;</span><span class="p">);</span>
 <span class="w">                </span><span class="n">DictionaryEncoding</span><span class="w"> </span><span class="n">dictionaryEncodingRead</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">appUseCountryDictionaryEncodedRead</span><span class="p">.</span><span class="na">getField</span><span class="p">().</span><span class="na">getDictionary</span><span class="p">();</span>
 <span class="w">                </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Dictionary-encoded ID recovered: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">dictionaryEncodingRead</span><span class="p">.</span><span class="na">getId</span><span class="p">());</span>
 <span class="w">                </span><span class="n">Dictionary</span><span class="w"> </span><span class="n">appUseCountryDictionaryRead</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">reader</span><span class="p">.</span><span class="na">getDictionaryVectors</span><span class="p">().</span><span class="na">get</span><span class="p">(</span><span class="n">dictionaryEncodingRead</span><span class="p">.</span><span class="na">getId</span><span class="p">());</span>
 <span class="w">                </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Dictionary-encoded data recovered: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">appUseCountryDictionaryEncodedRead</span><span class="p">);</span>
 <span class="w">                </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Dictionary recovered: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">appUseCountryDictionaryRead</span><span class="p">);</span>
 <span class="w">                </span><span class="k">try</span><span class="w"> </span><span class="p">(</span><span class="n">ValueVector</span><span class="w"> </span><span class="n">readVector</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">DictionaryEncoder</span><span class="p">.</span><span class="na">decode</span><span class="p">(</span><span class="n">appUseCountryDictionaryEncodedRead</span><span class="p">,</span><span class="w"> </span><span class="n">appUseCountryDictionaryRead</span><span class="p">))</span><span class="w"> </span><span class="p">{</span>
 <span class="w">                    </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Decoded data: &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">readVector</span><span class="p">);</span>
 <span class="w">                </span><span class="p">}</span>
 <span class="w">            </span><span class="p">}</span>
 <span class="w">        </span><span class="p">}</span>
 <span class="w">    </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">FileNotFoundException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">        </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
 <span class="w">    </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">        </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
 <span class="w">    </span><span class="p">}</span>
 <span class="p">}</span>
 </pre></div>
 </div>
 <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Dictionary: Dictionary DictionaryEncoding[id=666,ordered=false,indexType=Int(8, true)] [Andorra, Cuba, Grecia, Guinea, Islandia, Malta, Tailandia, Uganda, Yemen, Zambia]
 Unencoded data: [Andorra, Guinea, Islandia, Malta, Uganda]
 Dictionary-encoded data: [0, 3, 4, 5, 7]
 Dictionary-encoded ID: 666
 Record batches written: 1. Number of rows written: 5
 Dictionary-encoded ID recovered: 666
 Dictionary-encoded data recovered: [0, 3, 4, 5, 7]
 Dictionary recovered: Dictionary DictionaryEncoding[id=666,ordered=false,indexType=Int(8, true)] [Andorra, Cuba, Grecia, Guinea, Islandia, Malta, Tailandia, Uganda, Yemen, Zambia]
 Decoded data: [Andorra, Guinea, Islandia, Malta, Uganda]
 </pre></div>
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