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| <article class="container"> |
| <section class="col-md-12"> |
| <a class="edit-on-gh" href="https://github.com/apache/struts-site/edit/master/source/tag-developers/subset-tag.md" title="Edit this page on GitHub">Edit on GitHub</a> |
| |
| <a href="tag-reference.html" title="back to Tag Reference"><< back to Tag Reference</a> |
| |
| <h1 id="subset">subset</h1> |
| |
| <p>Please make sure you have read the <a href="tag-syntax">Tag Syntax</a> document and understand how tag attribute syntax works.</p> |
| |
| <h2 id="description">Description</h2> |
| |
| <p>A tag that takes an iterator and outputs a subset of it. It delegates to <code class="highlighter-rouge">org.apache.struts2.util.SubsetIteratorFilter</code> |
| internally to perform the subset functionality.</p> |
| |
| <p>Takes an iterator and outputs a subset of it.</p> |
| |
| <h2 id="attributes">Attributes</h2> |
| |
| <table width="100%"> |
| <tr> |
| <td colspan="6"><h4>Dynamic Attributes Allowed:</h4> false</td> |
| </tr> |
| <tr> |
| <td colspan="6"> </td> |
| </tr> |
| <tr> |
| <th align="left" valign="top"><h4>Name</h4></th> |
| <th align="left" valign="top"><h4>Required</h4></th> |
| <th align="left" valign="top"><h4>Default</h4></th> |
| <th align="left" valign="top"><h4>Evaluated</h4></th> |
| <th align="left" valign="top"><h4>Type</h4></th> |
| <th align="left" valign="top"><h4>Description</h4></th> |
| </tr> |
| <tr> |
| <td align="left" valign="top">count</td> |
| <td align="left" valign="top">false</td> |
| <td align="left" valign="top"></td> |
| <td align="left" valign="top">false</td> |
| <td align="left" valign="top">Integer</td> |
| <td align="left" valign="top">Indicate the number of entries to be in the resulting subset iterator</td> |
| </tr> |
| <tr> |
| <td align="left" valign="top">decider</td> |
| <td align="left" valign="top">false</td> |
| <td align="left" valign="top"></td> |
| <td align="left" valign="top">false</td> |
| <td align="left" valign="top">org.apache.struts2.util.SubsetIteratorFilter.Decider</td> |
| <td align="left" valign="top">Extension to plug-in a decider to determine if that particular entry is to be included in the resulting subset iterator</td> |
| </tr> |
| <tr> |
| <td align="left" valign="top">source</td> |
| <td align="left" valign="top">false</td> |
| <td align="left" valign="top"></td> |
| <td align="left" valign="top">false</td> |
| <td align="left" valign="top">String</td> |
| <td align="left" valign="top">Indicate the source of which the resulting subset iterator is to be derived base on</td> |
| </tr> |
| <tr> |
| <td align="left" valign="top">start</td> |
| <td align="left" valign="top">false</td> |
| <td align="left" valign="top"></td> |
| <td align="left" valign="top">false</td> |
| <td align="left" valign="top">Integer</td> |
| <td align="left" valign="top">Indicate the starting index (eg. first entry is 0) of entries in the source to be available as the first entry in the resulting subset iterator</td> |
| </tr> |
| <tr> |
| <td align="left" valign="top">var</td> |
| <td align="left" valign="top">false</td> |
| <td align="left" valign="top"></td> |
| <td align="left" valign="top">false</td> |
| <td align="left" valign="top">String</td> |
| <td align="left" valign="top">The name to store the resultant iterator into page context, if such name is supplied</td> |
| </tr> |
| </table> |
| |
| <h2 id="examples">Examples</h2> |
| |
| <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">public</span> <span class="kd">class</span> <span class="nc">MySubsetTagAction</span> <span class="kd">extends</span> <span class="n">ActionSupport</span> <span class="o">{</span> |
| <span class="kd">public</span> <span class="n">String</span> <span class="nf">execute</span><span class="o">()</span> <span class="kd">throws</span> <span class="n">Exception</span> <span class="o">{</span> |
| <span class="n">l</span> <span class="o">=</span> <span class="k">new</span> <span class="n">ArrayList</span><span class="o">();</span> |
| <span class="n">l</span><span class="o">.</span><span class="na">add</span><span class="o">(</span><span class="k">new</span> <span class="n">Integer</span><span class="o">(</span><span class="mi">1</span><span class="o">));</span> |
| <span class="n">l</span><span class="o">.</span><span class="na">add</span><span class="o">(</span><span class="k">new</span> <span class="n">Integer</span><span class="o">(</span><span class="mi">2</span><span class="o">));</span> |
| <span class="n">l</span><span class="o">.</span><span class="na">add</span><span class="o">(</span><span class="k">new</span> <span class="n">Integer</span><span class="o">(</span><span class="mi">3</span><span class="o">));</span> |
| <span class="n">l</span><span class="o">.</span><span class="na">add</span><span class="o">(</span><span class="k">new</span> <span class="n">Integer</span><span class="o">(</span><span class="mi">4</span><span class="o">));</span> |
| <span class="n">l</span><span class="o">.</span><span class="na">add</span><span class="o">(</span><span class="k">new</span> <span class="n">Integer</span><span class="o">(</span><span class="mi">5</span><span class="o">));</span> |
| <span class="k">return</span> <span class="s">"done"</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| |
| <span class="kd">public</span> <span class="n">Integer</span><span class="o">[]</span> <span class="nf">getMyArray</span><span class="o">()</span> <span class="o">{</span> |
| <span class="k">return</span> <span class="n">a</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="n">List</span> <span class="nf">getMyList</span><span class="o">()</span> <span class="o">{</span> |
| <span class="k">return</span> <span class="n">l</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="n">Decider</span> <span class="nf">getMyDecider</span><span class="o">()</span> <span class="o">{</span> |
| <span class="k">return</span> <span class="k">new</span> <span class="nf">Decider</span><span class="o">()</span> <span class="o">{</span> |
| <span class="kd">public</span> <span class="kt">boolean</span> <span class="nf">decide</span><span class="o">(</span><span class="n">Object</span> <span class="n">element</span><span class="o">)</span> <span class="kd">throws</span> <span class="n">Exception</span> <span class="o">{</span> |
| <span class="kt">int</span> <span class="n">i</span> <span class="o">=</span> <span class="o">((</span><span class="n">Integer</span><span class="o">)</span><span class="n">element</span><span class="o">).</span><span class="na">intValue</span><span class="o">();</span> |
| <span class="k">return</span> <span class="o">(((</span><span class="n">i</span> <span class="o">%</span> <span class="mi">2</span><span class="o">)</span> <span class="o">==</span> <span class="mi">0</span><span class="o">)?</span><span class="kc">true</span><span class="o">:</span><span class="kc">false</span><span class="o">);</span> |
| <span class="o">}</span> |
| <span class="o">};</span> |
| <span class="o">}</span> |
| <span class="o">}</span> |
| </code></pre></div></div> |
| |
| <p><strong>Basic example</strong></p> |
| |
| <pre><code class="language-jsp"><s:subset source="myList"> |
| <s:iterator> |
| <s:property /> |
| </s:iterator> |
| </s:subset> |
| </code></pre> |
| |
| <p><strong>List with count</strong></p> |
| |
| <div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt"><s:subset</span> <span class="na">source=</span><span class="s">"myList"</span> <span class="na">count=</span><span class="s">"3"</span><span class="nt">></span> |
| <span class="nt"><s:iterator></span> |
| <span class="nt"><s:property</span> <span class="nt">/></span> |
| <span class="nt"></s:iterator></span> |
| <span class="nt"></s:subset></span> |
| </code></pre></div></div> |
| |
| <p><strong>List with start</strong></p> |
| |
| <pre><code class="language-jsp"><s:subset source="myList" count="13" start="3"> |
| <s:iterator> |
| <s:property /> |
| </s:iterator> |
| </s:subset> |
| </code></pre> |
| |
| <p><strong>List with var</strong></p> |
| |
| <pre><code class="language-jsp"><s:subset var="mySubset" source="myList" count="13" start="3" /> |
| <% |
| Iterator i = (Iterator) pageContext.getAttribute("mySubset"); |
| while(i.hasNext()) { |
| %> |
| <%=i.next() %> |
| <% } %> |
| </code></pre> |
| |
| <p><strong>List with Decider</strong></p> |
| |
| <pre><code class="language-jsp"><s:subset source="myList" decider="myDecider"> |
| <s:iterator> |
| <s:property /> |
| </s:iterator> |
| </s:subset> |
| </code></pre> |
| |
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