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<div class="sub-title"><span class="package-label-in-type">Package</span>&nbsp;<a href="package-summary.html">org.apache.hadoop.hbase.util</a></div>
<h1 title="Class ObjectPool" class="title">Class ObjectPool&lt;K,<wbr>V&gt;</h1>
</div>
<div class="inheritance" title="Inheritance Tree"><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html" title="class or interface in java.lang" class="external-link">java.lang.Object</a>
<div class="inheritance">org.apache.hadoop.hbase.util.ObjectPool&lt;K,<wbr>V&gt;</div>
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<section class="class-description" id="class-description">
<dl class="notes">
<dt>Direct Known Subclasses:</dt>
<dd><code><a href="SoftObjectPool.html" title="class in org.apache.hadoop.hbase.util">SoftObjectPool</a></code>, <code><a href="WeakObjectPool.html" title="class in org.apache.hadoop.hbase.util">WeakObjectPool</a></code></dd>
</dl>
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<div class="type-signature"><span class="annotations">@Private
</span><span class="modifiers">public abstract class </span><span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-33">ObjectPool</a>&lt;K,<wbr>V&gt;</span>
<span class="extends-implements">extends <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html" title="class or interface in java.lang" class="external-link">Object</a></span></div>
<div class="block">A thread-safe shared object pool in which object creation is expected to be lightweight, and the
objects may be excessively created and discarded.</div>
</section>
<section class="summary">
<ul class="summary-list">
<!-- ======== NESTED CLASS SUMMARY ======== -->
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<h2>Nested Class Summary</h2>
<div class="caption"><span>Nested Classes</span></div>
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<div class="table-header col-first">Modifier and Type</div>
<div class="table-header col-second">Class</div>
<div class="table-header col-last">Description</div>
<div class="col-first even-row-color"><code>static interface&nbsp;</code></div>
<div class="col-second even-row-color"><code><a href="ObjectPool.ObjectFactory.html" class="type-name-link" title="interface in org.apache.hadoop.hbase.util">ObjectPool.ObjectFactory</a>&lt;<a href="ObjectPool.ObjectFactory.html" title="type parameter in ObjectPool.ObjectFactory">K</a>,<wbr><a href="ObjectPool.ObjectFactory.html" title="type parameter in ObjectPool.ObjectFactory">V</a>&gt;</code></div>
<div class="col-last even-row-color">
<div class="block">An <code>ObjectFactory</code> object is used to create new shared objects on demand.</div>
</div>
</div>
</section>
</li>
<!-- =========== FIELD SUMMARY =========== -->
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<section class="field-summary" id="field-summary">
<h2>Field Summary</h2>
<div class="caption"><span>Fields</span></div>
<div class="summary-table three-column-summary">
<div class="table-header col-first">Modifier and Type</div>
<div class="table-header col-second">Field</div>
<div class="table-header col-last">Description</div>
<div class="col-first even-row-color"><code>static final int</code></div>
<div class="col-second even-row-color"><code><a href="#DEFAULT_CONCURRENCY_LEVEL" class="member-name-link">DEFAULT_CONCURRENCY_LEVEL</a></code></div>
<div class="col-last even-row-color">
<div class="block">The default concurrency level, used when not otherwise specified in a constructor.</div>
</div>
<div class="col-first odd-row-color"><code>static final int</code></div>
<div class="col-second odd-row-color"><code><a href="#DEFAULT_INITIAL_CAPACITY" class="member-name-link">DEFAULT_INITIAL_CAPACITY</a></code></div>
<div class="col-last odd-row-color">
<div class="block">The default initial capacity, used when not otherwise specified in a constructor.</div>
</div>
<div class="col-first even-row-color"><code>private final <a href="ObjectPool.ObjectFactory.html" title="interface in org.apache.hadoop.hbase.util">ObjectPool.ObjectFactory</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>,<wbr><a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;</code></div>
<div class="col-second even-row-color"><code><a href="#objectFactory" class="member-name-link">objectFactory</a></code></div>
<div class="col-last even-row-color">&nbsp;</div>
<div class="col-first odd-row-color"><code>private final <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/locks/Lock.html" title="class or interface in java.util.concurrent.locks" class="external-link">Lock</a></code></div>
<div class="col-second odd-row-color"><code><a href="#purgeLock" class="member-name-link">purgeLock</a></code></div>
<div class="col-last odd-row-color">
<div class="block">For preventing parallel purge</div>
</div>
<div class="col-first even-row-color"><code>protected final <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/ConcurrentMap.html" title="class or interface in java.util.concurrent" class="external-link">ConcurrentMap</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>,<wbr><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/ref/Reference.html" title="class or interface in java.lang.ref" class="external-link">Reference</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;&gt;</code></div>
<div class="col-second even-row-color"><code><a href="#referenceCache" class="member-name-link">referenceCache</a></code></div>
<div class="col-last even-row-color">
<div class="block">Does not permit null keys.</div>
</div>
<div class="col-first odd-row-color"><code>protected final <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/ref/ReferenceQueue.html" title="class or interface in java.lang.ref" class="external-link">ReferenceQueue</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;</code></div>
<div class="col-second odd-row-color"><code><a href="#staleRefQueue" class="member-name-link">staleRefQueue</a></code></div>
<div class="col-last odd-row-color">&nbsp;</div>
</div>
</section>
</li>
<!-- ======== CONSTRUCTOR SUMMARY ======== -->
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<section class="constructor-summary" id="constructor-summary">
<h2>Constructor Summary</h2>
<div class="caption"><span>Constructors</span></div>
<div class="summary-table two-column-summary">
<div class="table-header col-first">Constructor</div>
<div class="table-header col-last">Description</div>
<div class="col-constructor-name even-row-color"><code><a href="#%3Cinit%3E(org.apache.hadoop.hbase.util.ObjectPool.ObjectFactory)" class="member-name-link">ObjectPool</a><wbr>(<a href="ObjectPool.ObjectFactory.html" title="interface in org.apache.hadoop.hbase.util">ObjectPool.ObjectFactory</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>,<wbr><a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;&nbsp;objectFactory)</code></div>
<div class="col-last even-row-color">
<div class="block">Creates a new pool with the default initial capacity (16) and the default concurrency level
(16).</div>
</div>
<div class="col-constructor-name odd-row-color"><code><a href="#%3Cinit%3E(org.apache.hadoop.hbase.util.ObjectPool.ObjectFactory,int)" class="member-name-link">ObjectPool</a><wbr>(<a href="ObjectPool.ObjectFactory.html" title="interface in org.apache.hadoop.hbase.util">ObjectPool.ObjectFactory</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>,<wbr><a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;&nbsp;objectFactory,
int&nbsp;initialCapacity)</code></div>
<div class="col-last odd-row-color">
<div class="block">Creates a new pool with the given initial capacity and the default concurrency level (16).</div>
</div>
<div class="col-constructor-name even-row-color"><code><a href="#%3Cinit%3E(org.apache.hadoop.hbase.util.ObjectPool.ObjectFactory,int,int)" class="member-name-link">ObjectPool</a><wbr>(<a href="ObjectPool.ObjectFactory.html" title="interface in org.apache.hadoop.hbase.util">ObjectPool.ObjectFactory</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>,<wbr><a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;&nbsp;objectFactory,
int&nbsp;initialCapacity,
int&nbsp;concurrencyLevel)</code></div>
<div class="col-last even-row-color">
<div class="block">Creates a new pool with the given initial capacity and the given concurrency level.</div>
</div>
</div>
</section>
</li>
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<h2>Method Summary</h2>
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<div class="summary-table three-column-summary" aria-labelledby="method-summary-table-tab0">
<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>abstract <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/ref/Reference.html" title="class or interface in java.lang.ref" class="external-link">Reference</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;</code></div>
<div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code><a href="#createReference(K,V)" class="member-name-link">createReference</a><wbr>(<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>&nbsp;key,
<a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&nbsp;obj)</code></div>
<div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3">
<div class="block">Create a reference associated with the given object</div>
</div>
<div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="ObjectPool.html" title="type parameter in ObjectPool">V</a></code></div>
<div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#get(K)" class="member-name-link">get</a><wbr>(<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>&nbsp;key)</code></div>
<div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4">
<div class="block">Returns a shared object associated with the given <code>key</code>, which is identified by the
<code>equals</code> method.</div>
</div>
<div class="col-first even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code>abstract <a href="ObjectPool.html" title="type parameter in ObjectPool">K</a></code></div>
<div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3"><code><a href="#getReferenceKey(java.lang.ref.Reference)" class="member-name-link">getReferenceKey</a><wbr>(<a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/ref/Reference.html" title="class or interface in java.lang.ref" class="external-link">Reference</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;&nbsp;ref)</code></div>
<div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab3">
<div class="block">Get key of the given reference</div>
</div>
<div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code>void</code></div>
<div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#purge()" class="member-name-link">purge</a>()</code></div>
<div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4">
<div class="block">Removes stale references of shared objects from the pool.</div>
</div>
<div class="col-first even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code>int</code></div>
<div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#size()" class="member-name-link">size</a>()</code></div>
<div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4">
<div class="block">Returns an estimated count of objects kept in the pool.</div>
</div>
</div>
</div>
</div>
<div class="inherited-list">
<h3 id="methods-inherited-from-class-java.lang.Object">Methods inherited from class&nbsp;java.lang.<a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html" title="class or interface in java.lang" class="external-link">Object</a></h3>
<code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#clone()" title="class or interface in java.lang" class="external-link">clone</a>, <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#equals(java.lang.Object)" title="class or interface in java.lang" class="external-link">equals</a>, <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#finalize()" title="class or interface in java.lang" class="external-link">finalize</a>, <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#getClass()" title="class or interface in java.lang" class="external-link">getClass</a>, <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#hashCode()" title="class or interface in java.lang" class="external-link">hashCode</a>, <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#notify()" title="class or interface in java.lang" class="external-link">notify</a>, <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#notifyAll()" title="class or interface in java.lang" class="external-link">notifyAll</a>, <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#toString()" title="class or interface in java.lang" class="external-link">toString</a>, <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#wait()" title="class or interface in java.lang" class="external-link">wait</a>, <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#wait(long)" title="class or interface in java.lang" class="external-link">wait</a>, <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html#wait(long,int)" title="class or interface in java.lang" class="external-link">wait</a></code></div>
</section>
</li>
</ul>
</section>
<section class="details">
<ul class="details-list">
<!-- ============ FIELD DETAIL =========== -->
<li>
<section class="field-details" id="field-detail">
<h2>Field Details</h2>
<ul class="member-list">
<li>
<section class="detail" id="staleRefQueue">
<h3>staleRefQueue</h3>
<div class="member-signature"><span class="modifiers">protected final</span>&nbsp;<span class="return-type"><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/ref/ReferenceQueue.html" title="class or interface in java.lang.ref" class="external-link">ReferenceQueue</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-47">staleRefQueue</a></span></div>
</section>
</li>
<li>
<section class="detail" id="objectFactory">
<h3>objectFactory</h3>
<div class="member-signature"><span class="modifiers">private final</span>&nbsp;<span class="return-type"><a href="ObjectPool.ObjectFactory.html" title="interface in org.apache.hadoop.hbase.util">ObjectPool.ObjectFactory</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>,<wbr><a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-49">objectFactory</a></span></div>
</section>
</li>
<li>
<section class="detail" id="referenceCache">
<h3>referenceCache</h3>
<div class="member-signature"><span class="modifiers">protected final</span>&nbsp;<span class="return-type"><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/ConcurrentMap.html" title="class or interface in java.util.concurrent" class="external-link">ConcurrentMap</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>,<wbr><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/ref/Reference.html" title="class or interface in java.lang.ref" class="external-link">Reference</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;&gt;</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-52">referenceCache</a></span></div>
<div class="block">Does not permit null keys.</div>
</section>
</li>
<li>
<section class="detail" id="purgeLock">
<h3>purgeLock</h3>
<div class="member-signature"><span class="modifiers">private final</span>&nbsp;<span class="return-type"><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/locks/Lock.html" title="class or interface in java.util.concurrent.locks" class="external-link">Lock</a></span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-55">purgeLock</a></span></div>
<div class="block">For preventing parallel purge</div>
</section>
</li>
<li>
<section class="detail" id="DEFAULT_INITIAL_CAPACITY">
<h3>DEFAULT_INITIAL_CAPACITY</h3>
<div class="member-signature"><span class="modifiers">public static final</span>&nbsp;<span class="return-type">int</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-60">DEFAULT_INITIAL_CAPACITY</a></span></div>
<div class="block">The default initial capacity, used when not otherwise specified in a constructor.</div>
<dl class="notes">
<dt>See Also:</dt>
<dd>
<ul class="see-list">
<li><a href="../../../../../constant-values.html#org.apache.hadoop.hbase.util.ObjectPool.DEFAULT_INITIAL_CAPACITY">Constant Field Values</a></li>
</ul>
</dd>
</dl>
</section>
</li>
<li>
<section class="detail" id="DEFAULT_CONCURRENCY_LEVEL">
<h3>DEFAULT_CONCURRENCY_LEVEL</h3>
<div class="member-signature"><span class="modifiers">public static final</span>&nbsp;<span class="return-type">int</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-65">DEFAULT_CONCURRENCY_LEVEL</a></span></div>
<div class="block">The default concurrency level, used when not otherwise specified in a constructor.</div>
<dl class="notes">
<dt>See Also:</dt>
<dd>
<ul class="see-list">
<li><a href="../../../../../constant-values.html#org.apache.hadoop.hbase.util.ObjectPool.DEFAULT_CONCURRENCY_LEVEL">Constant Field Values</a></li>
</ul>
</dd>
</dl>
</section>
</li>
</ul>
</section>
</li>
<!-- ========= CONSTRUCTOR DETAIL ======== -->
<li>
<section class="constructor-details" id="constructor-detail">
<h2>Constructor Details</h2>
<ul class="member-list">
<li>
<section class="detail" id="&lt;init&gt;(org.apache.hadoop.hbase.util.ObjectPool.ObjectFactory)">
<h3>ObjectPool</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-73">ObjectPool</a></span><wbr><span class="parameters">(<a href="ObjectPool.ObjectFactory.html" title="interface in org.apache.hadoop.hbase.util">ObjectPool.ObjectFactory</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>,<wbr><a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;&nbsp;objectFactory)</span></div>
<div class="block">Creates a new pool with the default initial capacity (16) and the default concurrency level
(16).</div>
<dl class="notes">
<dt>Parameters:</dt>
<dd><code>objectFactory</code> - the factory to supply new objects on demand</dd>
<dt>Throws:</dt>
<dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/NullPointerException.html" title="class or interface in java.lang" class="external-link">NullPointerException</a></code> - if <code>objectFactory</code> is <code>null</code></dd>
</dl>
</section>
</li>
<li>
<section class="detail" id="&lt;init&gt;(org.apache.hadoop.hbase.util.ObjectPool.ObjectFactory,int)">
<h3>ObjectPool</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-84">ObjectPool</a></span><wbr><span class="parameters">(<a href="ObjectPool.ObjectFactory.html" title="interface in org.apache.hadoop.hbase.util">ObjectPool.ObjectFactory</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>,<wbr><a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;&nbsp;objectFactory,
int&nbsp;initialCapacity)</span></div>
<div class="block">Creates a new pool with the given initial capacity and the default concurrency level (16).</div>
<dl class="notes">
<dt>Parameters:</dt>
<dd><code>objectFactory</code> - the factory to supply new objects on demand</dd>
<dd><code>initialCapacity</code> - the initial capacity to keep objects in the pool</dd>
<dt>Throws:</dt>
<dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/NullPointerException.html" title="class or interface in java.lang" class="external-link">NullPointerException</a></code> - if <code>objectFactory</code> is <code>null</code></dd>
<dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/IllegalArgumentException.html" title="class or interface in java.lang" class="external-link">IllegalArgumentException</a></code> - if <code>initialCapacity</code> is negative</dd>
</dl>
</section>
</li>
<li>
<section class="detail" id="&lt;init&gt;(org.apache.hadoop.hbase.util.ObjectPool.ObjectFactory,int,int)">
<h3>ObjectPool</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-97">ObjectPool</a></span><wbr><span class="parameters">(<a href="ObjectPool.ObjectFactory.html" title="interface in org.apache.hadoop.hbase.util">ObjectPool.ObjectFactory</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>,<wbr><a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;&nbsp;objectFactory,
int&nbsp;initialCapacity,
int&nbsp;concurrencyLevel)</span></div>
<div class="block">Creates a new pool with the given initial capacity and the given concurrency level.</div>
<dl class="notes">
<dt>Parameters:</dt>
<dd><code>objectFactory</code> - the factory to supply new objects on demand</dd>
<dd><code>initialCapacity</code> - the initial capacity to keep objects in the pool</dd>
<dd><code>concurrencyLevel</code> - the estimated count of concurrently accessing threads</dd>
<dt>Throws:</dt>
<dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/NullPointerException.html" title="class or interface in java.lang" class="external-link">NullPointerException</a></code> - if <code>objectFactory</code> is <code>null</code></dd>
<dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/IllegalArgumentException.html" title="class or interface in java.lang" class="external-link">IllegalArgumentException</a></code> - if <code>initialCapacity</code> is negative or
<code>concurrencyLevel</code> is non-positive</dd>
</dl>
</section>
</li>
</ul>
</section>
</li>
<!-- ============ METHOD DETAIL ========== -->
<li>
<section class="method-details" id="method-detail">
<h2>Method Details</h2>
<ul class="member-list">
<li>
<section class="detail" id="purge()">
<h3>purge</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="return-type">void</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-113">purge</a></span>()</div>
<div class="block">Removes stale references of shared objects from the pool. References newly becoming stale may
still remain.
<p/>
The implementation of this method is expected to be lightweight when there is no stale
reference with the Oracle (Sun) implementation of <code>ReferenceQueue</code>, because
<code>ReferenceQueue.poll</code> just checks a volatile instance variable in <code>ReferenceQueue</code>.</div>
</section>
</li>
<li>
<section class="detail" id="createReference(K,V)">
<h3 id="createReference(java.lang.Object,java.lang.Object)">createReference</h3>
<div class="member-signature"><span class="modifiers">public abstract</span>&nbsp;<span class="return-type"><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/ref/Reference.html" title="class or interface in java.lang.ref" class="external-link">Reference</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-136">createReference</a></span><wbr><span class="parameters">(<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>&nbsp;key,
<a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&nbsp;obj)</span></div>
<div class="block">Create a reference associated with the given object</div>
<dl class="notes">
<dt>Parameters:</dt>
<dd><code>key</code> - the key to store in the reference</dd>
<dd><code>obj</code> - the object to associate with</dd>
<dt>Returns:</dt>
<dd>the reference instance</dd>
</dl>
</section>
</li>
<li>
<section class="detail" id="getReferenceKey(java.lang.ref.Reference)">
<h3>getReferenceKey</h3>
<div class="member-signature"><span class="modifiers">public abstract</span>&nbsp;<span class="return-type"><a href="ObjectPool.html" title="type parameter in ObjectPool">K</a></span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-143">getReferenceKey</a></span><wbr><span class="parameters">(<a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/ref/Reference.html" title="class or interface in java.lang.ref" class="external-link">Reference</a>&lt;<a href="ObjectPool.html" title="type parameter in ObjectPool">V</a>&gt;&nbsp;ref)</span></div>
<div class="block">Get key of the given reference</div>
<dl class="notes">
<dt>Parameters:</dt>
<dd><code>ref</code> - The reference</dd>
<dt>Returns:</dt>
<dd>key of the reference</dd>
</dl>
</section>
</li>
<li>
<section class="detail" id="get(K)">
<h3 id="get(java.lang.Object)">get</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="return-type"><a href="ObjectPool.html" title="type parameter in ObjectPool">V</a></span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-150">get</a></span><wbr><span class="parameters">(<a href="ObjectPool.html" title="type parameter in ObjectPool">K</a>&nbsp;key)</span></div>
<div class="block">Returns a shared object associated with the given <code>key</code>, which is identified by the
<code>equals</code> method.</div>
<dl class="notes">
<dt>Throws:</dt>
<dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/NullPointerException.html" title="class or interface in java.lang" class="external-link">NullPointerException</a></code> - if <code>key</code> is <code>null</code></dd>
</dl>
</section>
</li>
<li>
<section class="detail" id="size()">
<h3>size</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="return-type">int</span>&nbsp;<span class="element-name"><a href="../../../../../src-html/org/apache/hadoop/hbase/util/ObjectPool.html#line-180">size</a></span>()</div>
<div class="block">Returns an estimated count of objects kept in the pool. This also counts stale references, and
you might want to call <a href="#purge()"><code>purge()</code></a> beforehand.</div>
</section>
</li>
</ul>
</section>
</li>
</ul>
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