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| <div class="sub-title"><span class="package-label-in-type">Package</span> <a href="package-summary.html">org.apache.hadoop.hbase.wal</a></div> |
| <h1 title="Interface WALTailingReader" class="title">Interface WALTailingReader</h1> |
| </div> |
| <section class="class-description" id="class-description"> |
| <dl class="notes"> |
| <dt>All Superinterfaces:</dt> |
| <dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/AutoCloseable.html" title="class or interface in java.lang" class="external-link">AutoCloseable</a></code>, <code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/io/Closeable.html" title="class or interface in java.io" class="external-link">Closeable</a></code></dd> |
| </dl> |
| <dl class="notes"> |
| <dt>All Known Implementing Classes:</dt> |
| <dd><code><a href="../regionserver/wal/ProtobufWALTailingReader.html" title="class in org.apache.hadoop.hbase.regionserver.wal">ProtobufWALTailingReader</a></code></dd> |
| </dl> |
| <hr> |
| <div class="type-signature"><span class="annotations">@Private |
| </span><span class="modifiers">public interface </span><span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/wal/WALTailingReader.html#line-29">WALTailingReader</a></span><span class="extends-implements"> |
| extends <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/io/Closeable.html" title="class or interface in java.io" class="external-link">Closeable</a></span></div> |
| <div class="block">A WAL reader which is designed for be able to tailing the WAL file which is currently being |
| written. It adds support</div> |
| </section> |
| <section class="summary"> |
| <ul class="summary-list"> |
| <!-- ======== NESTED CLASS SUMMARY ======== --> |
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| <div class="table-header col-first">Modifier and Type</div> |
| <div class="table-header col-second">Interface</div> |
| <div class="table-header col-last">Description</div> |
| <div class="col-first even-row-color"><code>static final class </code></div> |
| <div class="col-second even-row-color"><code><a href="WALTailingReader.Result.html" class="type-name-link" title="class in org.apache.hadoop.hbase.wal">WALTailingReader.Result</a></code></div> |
| <div class="col-last even-row-color"> </div> |
| <div class="col-first odd-row-color"><code>static enum </code></div> |
| <div class="col-second odd-row-color"><code><a href="WALTailingReader.State.html" class="type-name-link" title="enum class in org.apache.hadoop.hbase.wal">WALTailingReader.State</a></code></div> |
| <div class="col-last odd-row-color"> </div> |
| </div> |
| </section> |
| </li> |
| <!-- ========== METHOD SUMMARY =========== --> |
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| <section class="method-summary" id="method-summary"> |
| <h2>Method Summary</h2> |
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| <div class="table-header col-first">Modifier and Type</div> |
| <div class="table-header col-second">Method</div> |
| <div class="table-header col-last">Description</div> |
| <div class="col-first even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code>void</code></div> |
| <div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code><a href="#close()" class="member-name-link">close</a>()</code></div> |
| <div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"> |
| <div class="block">Override to remove the 'throws IOException' as we are just a reader.</div> |
| </div> |
| <div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code>long</code></div> |
| <div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code><a href="#getPosition()" class="member-name-link">getPosition</a>()</code></div> |
| <div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"> |
| <div class="block">Get the current reading position.</div> |
| </div> |
| <div class="col-first even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code><a href="WALTailingReader.Result.html" title="class in org.apache.hadoop.hbase.wal">WALTailingReader.Result</a></code></div> |
| <div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code><a href="#next(long)" class="member-name-link">next</a><wbr>(long limit)</code></div> |
| <div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"> |
| <div class="block">Read the next entry and make sure the position after reading does not go beyond the given |
| <code>limit</code>.</div> |
| </div> |
| <div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code>void</code></div> |
| <div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code><a href="#resetTo(long,boolean)" class="member-name-link">resetTo</a><wbr>(long position, |
| boolean resetCompression)</code></div> |
| <div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"> |
| <div class="block">Reopen the reader to see if there is new data arrives, and also seek(or skip) to the given |
| position.</div> |
| </div> |
| </div> |
| </div> |
| </div> |
| </section> |
| </li> |
| </ul> |
| </section> |
| <section class="details"> |
| <ul class="details-list"> |
| <!-- ============ METHOD DETAIL ========== --> |
| <li> |
| <section class="method-details" id="method-detail"> |
| <h2>Method Details</h2> |
| <ul class="member-list"> |
| <li> |
| <section class="detail" id="next(long)"> |
| <h3>next</h3> |
| <div class="member-signature"><span class="return-type"><a href="WALTailingReader.Result.html" title="class in org.apache.hadoop.hbase.wal">WALTailingReader.Result</a></span> <span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/wal/WALTailingReader.html#line-121">next</a></span><wbr><span class="parameters">(long limit)</span></div> |
| <div class="block">Read the next entry and make sure the position after reading does not go beyond the given |
| <code>limit</code>. |
| <p/> |
| Notice that we will not throw any checked exception out, all the states are represented by the |
| return value. Of course we will log the exceptions out. The reason why we do this is that, for |
| tailing a WAL file which is currently being written, we will hit EOFException many times, so it |
| should not be considered as an 'exception' and also, creating an Exception is a bit expensive.</div> |
| <dl class="notes"> |
| <dt>Parameters:</dt> |
| <dd><code>limit</code> - the position limit. See HBASE-14004 for more details about why we need this |
| limitation. -1 means no limit.</dd> |
| </dl> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="getPosition()"> |
| <h3>getPosition</h3> |
| <div class="member-signature"><span class="return-type">long</span> <span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/wal/WALTailingReader.html#line-126">getPosition</a></span>() |
| throws <span class="exceptions"><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/io/IOException.html" title="class or interface in java.io" class="external-link">IOException</a></span></div> |
| <div class="block">Get the current reading position.</div> |
| <dl class="notes"> |
| <dt>Throws:</dt> |
| <dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/io/IOException.html" title="class or interface in java.io" class="external-link">IOException</a></code></dd> |
| </dl> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="resetTo(long,boolean)"> |
| <h3>resetTo</h3> |
| <div class="member-signature"><span class="return-type">void</span> <span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/wal/WALTailingReader.html#line-141">resetTo</a></span><wbr><span class="parameters">(long position, |
| boolean resetCompression)</span> |
| throws <span class="exceptions"><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/io/IOException.html" title="class or interface in java.io" class="external-link">IOException</a></span></div> |
| <div class="block">Reopen the reader to see if there is new data arrives, and also seek(or skip) to the given |
| position. |
| <p/> |
| If you want to read from the beginning instead of a given position, please pass -1 as |
| <code>position</code>, then the reader will locate to the first entry. Notice that, since we have a |
| magic header and a pb header, the first WAL entry is not located at position 0, so passing 0 |
| will cause trouble.</div> |
| <dl class="notes"> |
| <dt>Parameters:</dt> |
| <dd><code>position</code> - the position we want to start reading from after resetting, or -1 if |
| you want to start reading from the beginning.</dd> |
| <dd><code>resetCompression</code> - whether we also need to clear the compression context. If <code>true</code>, |
| we will use skip instead of seek after resetting.</dd> |
| <dt>Throws:</dt> |
| <dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/io/IOException.html" title="class or interface in java.io" class="external-link">IOException</a></code></dd> |
| </dl> |
| </section> |
| </li> |
| <li> |
| <section class="detail" id="close()"> |
| <h3>close</h3> |
| <div class="member-signature"><span class="return-type">void</span> <span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/wal/WALTailingReader.html#line-146">close</a></span>()</div> |
| <div class="block">Override to remove the 'throws IOException' as we are just a reader.</div> |
| <dl class="notes"> |
| <dt>Specified by:</dt> |
| <dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/AutoCloseable.html#close()" title="class or interface in java.lang" class="external-link">close</a></code> in interface <code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/AutoCloseable.html" title="class or interface in java.lang" class="external-link">AutoCloseable</a></code></dd> |
| <dt>Specified by:</dt> |
| <dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/io/Closeable.html#close()" title="class or interface in java.io" class="external-link">close</a></code> in interface <code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/io/Closeable.html" title="class or interface in java.io" class="external-link">Closeable</a></code></dd> |
| </dl> |
| </section> |
| </li> |
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