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<div class="subTitle">org.apache.commons.lang3.concurrent</div>
<h2 title="Class AtomicSafeInitializer" class="title">Class AtomicSafeInitializer<T></h2>
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<dt><span class="paramLabel">Type Parameters:</span></dt>
<dd><code>T</code> - the type of the object managed by this initializer class</dd>
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<dl>
<dt>All Implemented Interfaces:</dt>
<dd><a href="../../../../../org/apache/commons/lang3/concurrent/ConcurrentInitializer.html" title="interface in org.apache.commons.lang3.concurrent">ConcurrentInitializer</a><T></dd>
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<pre>public abstract class <span class="typeNameLabel">AtomicSafeInitializer<T></span>
extends <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</a>
implements <a href="../../../../../org/apache/commons/lang3/concurrent/ConcurrentInitializer.html" title="interface in org.apache.commons.lang3.concurrent">ConcurrentInitializer</a><T></pre>
<div class="block"><p>
A specialized <code>ConcurrentInitializer</code> implementation which is similar
to <a href="../../../../../org/apache/commons/lang3/concurrent/AtomicInitializer.html" title="class in org.apache.commons.lang3.concurrent"><code>AtomicInitializer</code></a>, but ensures that the <a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html#initialize--"><code>initialize()</code></a>
method is called only once.
</p>
<p>
As <a href="../../../../../org/apache/commons/lang3/concurrent/AtomicInitializer.html" title="class in org.apache.commons.lang3.concurrent"><code>AtomicInitializer</code></a> this class is based on atomic variables, so it
can create an object under concurrent access without synchronization.
However, it implements an additional check to guarantee that the
<a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html#initialize--"><code>initialize()</code></a> method which actually creates the object cannot be
called multiple times.
</p>
<p>
Because of this additional check this implementation is slightly less
efficient than <a href="../../../../../org/apache/commons/lang3/concurrent/AtomicInitializer.html" title="class in org.apache.commons.lang3.concurrent"><code>AtomicInitializer</code></a>, but if the object creation in the
<code>initialize()</code> method is expensive or if multiple invocations of
<code>initialize()</code> are problematic, it is the better alternative.
</p>
<p>
From its semantics this class has the same properties as
<a href="../../../../../org/apache/commons/lang3/concurrent/LazyInitializer.html" title="class in org.apache.commons.lang3.concurrent"><code>LazyInitializer</code></a>. It is a "save" implementation of the lazy
initializer pattern. Comparing both classes in terms of efficiency is
difficult because which one is faster depends on multiple factors. Because
<code>AtomicSafeInitializer</code> does not use synchronization at all it probably
outruns <a href="../../../../../org/apache/commons/lang3/concurrent/LazyInitializer.html" title="class in org.apache.commons.lang3.concurrent"><code>LazyInitializer</code></a>, at least under low or moderate concurrent
access. Developers should run their own benchmarks on the expected target
platform to decide which implementation is suitable for their specific use
case.
</p></div>
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<dt><span class="simpleTagLabel">Since:</span></dt>
<dd>3.0</dd>
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<td class="colOne"><code><span class="memberNameLink"><a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html#AtomicSafeInitializer--">AtomicSafeInitializer</a></span>()</code> </td>
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<td class="colFirst"><code><a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html" title="type parameter in AtomicSafeInitializer">T</a></code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html#get--">get</a></span>()</code>
<div class="block">Get (and initialize, if not initialized yet) the required object</div>
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<tr id="i1" class="rowColor">
<td class="colFirst"><code>protected abstract <a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html" title="type parameter in AtomicSafeInitializer">T</a></code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html#initialize--">initialize</a></span>()</code>
<div class="block">Creates and initializes the object managed by this
<code>AtomicInitializer</code>.</div>
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<code><a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#clone--" title="class or interface in java.lang">clone</a>, <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#equals-java.lang.Object-" title="class or interface in java.lang">equals</a>, <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#finalize--" title="class or interface in java.lang">finalize</a>, <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#getClass--" title="class or interface in java.lang">getClass</a>, <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#hashCode--" title="class or interface in java.lang">hashCode</a>, <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#notify--" title="class or interface in java.lang">notify</a>, <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#notifyAll--" title="class or interface in java.lang">notifyAll</a>, <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#toString--" title="class or interface in java.lang">toString</a>, <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#wait--" title="class or interface in java.lang">wait</a>, <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#wait-long-" title="class or interface in java.lang">wait</a>, <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html?is-external=true#wait-long-int-" title="class or interface in java.lang">wait</a></code></li>
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<h4>AtomicSafeInitializer</h4>
<pre>public AtomicSafeInitializer()</pre>
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<h4>get</h4>
<pre>public final <a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html" title="type parameter in AtomicSafeInitializer">T</a> get()
throws <a href="../../../../../org/apache/commons/lang3/concurrent/ConcurrentException.html" title="class in org.apache.commons.lang3.concurrent">ConcurrentException</a></pre>
<div class="block">Get (and initialize, if not initialized yet) the required object</div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../../../org/apache/commons/lang3/concurrent/ConcurrentInitializer.html#get--">get</a></code> in interface <code><a href="../../../../../org/apache/commons/lang3/concurrent/ConcurrentInitializer.html" title="interface in org.apache.commons.lang3.concurrent">ConcurrentInitializer</a><<a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html" title="type parameter in AtomicSafeInitializer">T</a>></code></dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>lazily initialized object</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../../../org/apache/commons/lang3/concurrent/ConcurrentException.html" title="class in org.apache.commons.lang3.concurrent">ConcurrentException</a></code> - if the initialization of the object causes an
exception</dd>
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<h4>initialize</h4>
<pre>protected abstract <a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html" title="type parameter in AtomicSafeInitializer">T</a> initialize()
throws <a href="../../../../../org/apache/commons/lang3/concurrent/ConcurrentException.html" title="class in org.apache.commons.lang3.concurrent">ConcurrentException</a></pre>
<div class="block">Creates and initializes the object managed by this
<code>AtomicInitializer</code>. This method is called by <a href="../../../../../org/apache/commons/lang3/concurrent/AtomicSafeInitializer.html#get--"><code>get()</code></a> when
the managed object is not available yet. An implementation can focus on
the creation of the object. No synchronization is needed, as this is
already handled by <code>get()</code>. This method is guaranteed to be called
only once.</div>
<dl>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the managed data object</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../../../org/apache/commons/lang3/concurrent/ConcurrentException.html" title="class in org.apache.commons.lang3.concurrent">ConcurrentException</a></code> - if an error occurs during object creation</dd>
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