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 <H2>
 <FONT SIZE="-1">
 com.google.common.collect</FONT>
 <BR>
 Class MapMaker</H2>
 <PRE>
 <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">java.lang.Object</A>
   <IMG SRC="../../../../resources/inherit.gif" ALT="extended by "><B>com.google.common.collect.MapMaker</B>
 </PRE>
 <HR>
 <DL>
 <DT><PRE>public final class <B>MapMaker</B><DT>extends <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</A></DL>
 </PRE>

 <P>
 A <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentMap.html?is-external=true" title="class or interface in java.util.concurrent"><CODE>ConcurrentMap</CODE></A> builder, providing any combination of these
  features: <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/SoftReference.html?is-external=true" title="class or interface in java.lang.ref">soft</A> or <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/WeakReference.html?is-external=true" title="class or interface in java.lang.ref">weak</A> keys, soft or weak values, timed expiration, and on-demand
  computation of values. Usage example: <pre> <code>ConcurrentMap&lt;Key, Graph&gt; graphs = new MapMaker()
        .concurrencyLevel(32)
        .softKeys()
        .weakValues()
        .expiration(30, TimeUnit.MINUTES)
        .makeComputingMap(
            new Function&lt;Key, Graph&gt;() {
              public Graph apply(Key key) {
                return createExpensiveGraph(key);
              }
            });</code></pre>

  These features are all optional; <code>new MapMaker().makeMap()</code>
  returns a valid concurrent map that behaves exactly like a
  <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentHashMap.html?is-external=true" title="class or interface in java.util.concurrent"><CODE>ConcurrentHashMap</CODE></A>.

  The returned map is implemented as a hash table with similar performance
  characteristics to <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentHashMap.html?is-external=true" title="class or interface in java.util.concurrent"><CODE>ConcurrentHashMap</CODE></A>. It supports all optional
  operations of the <code>ConcurrentMap</code> interface. It does not permit
  null keys or values. It is serializable; however, serializing a map that
  uses soft or weak references can give unpredictable results.

  <p><b>Note:</b> by default, the returned map uses equality comparisons
  (the <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#equals(java.lang.Object)" title="class or interface in java.lang"><CODE>equals</CODE></A> method) to determine equality
  for keys or values. However, if <A HREF="../../../../com/google/common/collect/MapMaker.html#weakKeys()"><CODE>weakKeys()</CODE></A> or <A HREF="../../../../com/google/common/collect/MapMaker.html#softKeys()"><CODE>softKeys()</CODE></A> was specified, the map uses identity (<code>==</code>)
  comparisons instead for keys. Likewise, if <A HREF="../../../../com/google/common/collect/MapMaker.html#weakValues()"><CODE>weakValues()</CODE></A> or
  <A HREF="../../../../com/google/common/collect/MapMaker.html#softValues()"><CODE>softValues()</CODE></A> was specified, the map uses identity comparisons
  for values.

  <p>The returned map has <i>weakly consistent iteration</i>: an iterator
  over one of the map's view collections may reflect some, all or none of
  the changes made to the map after the iterator was created.

  <p>An entry whose key or value is reclaimed by the garbage collector
  immediately disappears from the map. (If the default settings of strong
  keys and strong values are used, this will never happen.) The client can
  never observe a partially-reclaimed entry. Any <A HREF="http://java.sun.com/javase/6/docs/api/java/util/Map.Entry.html?is-external=true" title="class or interface in java.util"><CODE>Map.Entry</CODE></A>
  instance retrieved from the map's <A HREF="http://java.sun.com/javase/6/docs/api/java/util/Map.html?is-external=true#entrySet()" title="class or interface in java.util">entry set</A>
  is snapshot of that entry's state at the time of retrieval.

  <p><code>new MapMaker().weakKeys().makeMap()</code> can almost always be
  used as a drop-in replacement for <A HREF="http://java.sun.com/javase/6/docs/api/java/util/WeakHashMap.html?is-external=true" title="class or interface in java.util"><CODE>WeakHashMap</CODE></A>, adding
  concurrency, asynchronous cleanup, identity-based equality for keys, and
  great flexibility.
 <P>

 <P>
 <DL>
 <DT><B>Since:</B></DT>
   <DD>2010.01.04 <b>stable</b> (imported from Google Collections Library)</DD>
 <DT><B>Author:</B></DT>
   <DD>Bob Lee, Kevin Bourrillion</DD>
 </DL>
 <HR>

 <P>

 <!-- ======== CONSTRUCTOR SUMMARY ======== -->

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 <TR BGCOLOR="white" CLASS="TableRowColor">
 <TD><CODE><B><A HREF="../../../../com/google/common/collect/MapMaker.html#MapMaker()">MapMaker</A></B>()</CODE>

 <BR>
 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Constructs a new <code>MapMaker</code> instance with default settings,
  including strong keys, strong values, and no automatic expiration.</TD>
 </TR>
 </TABLE>
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 <!-- ========== METHOD SUMMARY =========== -->

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 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
 <CODE>&nbsp;<A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A></CODE></FONT></TD>
 <TD><CODE><B><A HREF="../../../../com/google/common/collect/MapMaker.html#concurrencyLevel(int)">concurrencyLevel</A></B>(int&nbsp;concurrencyLevel)</CODE>

 <BR>
 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Guides the allowed concurrency among update operations.</TD>
 </TR>
 <TR BGCOLOR="white" CLASS="TableRowColor">
 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
 <CODE>&nbsp;<A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A></CODE></FONT></TD>
 <TD><CODE><B><A HREF="../../../../com/google/common/collect/MapMaker.html#expiration(long, java.util.concurrent.TimeUnit)">expiration</A></B>(long&nbsp;duration,
            <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/TimeUnit.html?is-external=true" title="class or interface in java.util.concurrent">TimeUnit</A>&nbsp;unit)</CODE>

 <BR>
 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Specifies that each entry should be automatically removed from the
  map once a fixed duration has passed since the entry's creation.</TD>
 </TR>
 <TR BGCOLOR="white" CLASS="TableRowColor">
 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
 <CODE>&nbsp;<A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A></CODE></FONT></TD>
 <TD><CODE><B><A HREF="../../../../com/google/common/collect/MapMaker.html#initialCapacity(int)">initialCapacity</A></B>(int&nbsp;initialCapacity)</CODE>

 <BR>
 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Sets a custom initial capacity (defaults to 16).</TD>
 </TR>
 <TR BGCOLOR="white" CLASS="TableRowColor">
 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
 <CODE>
 <TABLE BORDER="0" CELLPADDING="0" CELLSPACING="0" SUMMARY="">
 <TR ALIGN="right" VALIGN="">
 <TD NOWRAP><FONT SIZE="-1">
 <CODE>&lt;K,V&gt; <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentMap.html?is-external=true" title="class or interface in java.util.concurrent">ConcurrentMap</A>&lt;K,V&gt;</CODE></FONT></TD>
 </TR>
 </TABLE>
 </CODE></FONT></TD>
 <TD><CODE><B><A HREF="../../../../com/google/common/collect/MapMaker.html#makeComputingMap(com.google.common.base.Function)">makeComputingMap</A></B>(<A HREF="../../../../com/google/common/base/Function.html" title="interface in com.google.common.base">Function</A>&lt;? super K,? extends V&gt;&nbsp;computingFunction)</CODE>

 <BR>
 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Builds a map that supports atomic, on-demand computation of values.</TD>
 </TR>
 <TR BGCOLOR="white" CLASS="TableRowColor">
 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
 <CODE>
 <TABLE BORDER="0" CELLPADDING="0" CELLSPACING="0" SUMMARY="">
 <TR ALIGN="right" VALIGN="">
 <TD NOWRAP><FONT SIZE="-1">
 <CODE>&lt;K,V&gt; <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentMap.html?is-external=true" title="class or interface in java.util.concurrent">ConcurrentMap</A>&lt;K,V&gt;</CODE></FONT></TD>
 </TR>
 </TABLE>
 </CODE></FONT></TD>
 <TD><CODE><B><A HREF="../../../../com/google/common/collect/MapMaker.html#makeMap()">makeMap</A></B>()</CODE>

 <BR>
 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Builds the final map, without on-demand computation of values.</TD>
 </TR>
 <TR BGCOLOR="white" CLASS="TableRowColor">
 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
 <CODE>&nbsp;<A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A></CODE></FONT></TD>
 <TD><CODE><B><A HREF="../../../../com/google/common/collect/MapMaker.html#softKeys()">softKeys</A></B>()</CODE>

 <BR>
 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Specifies that each key (not value) stored in the map should be
  wrapped in a <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/SoftReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>SoftReference</CODE></A> (by default, strong references
  are used).</TD>
 </TR>
 <TR BGCOLOR="white" CLASS="TableRowColor">
 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
 <CODE>&nbsp;<A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A></CODE></FONT></TD>
 <TD><CODE><B><A HREF="../../../../com/google/common/collect/MapMaker.html#softValues()">softValues</A></B>()</CODE>

 <BR>
 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Specifies that each value (not key) stored in the map should be
  wrapped in a <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/SoftReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>SoftReference</CODE></A> (by default, strong references
  are used).</TD>
 </TR>
 <TR BGCOLOR="white" CLASS="TableRowColor">
 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
 <CODE>&nbsp;<A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A></CODE></FONT></TD>
 <TD><CODE><B><A HREF="../../../../com/google/common/collect/MapMaker.html#weakKeys()">weakKeys</A></B>()</CODE>

 <BR>
 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Specifies that each key (not value) stored in the map should be
  wrapped in a <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/WeakReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>WeakReference</CODE></A> (by default, strong references
  are used).</TD>
 </TR>
 <TR BGCOLOR="white" CLASS="TableRowColor">
 <TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
 <CODE>&nbsp;<A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A></CODE></FONT></TD>
 <TD><CODE><B><A HREF="../../../../com/google/common/collect/MapMaker.html#weakValues()">weakValues</A></B>()</CODE>

 <BR>
 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Specifies that each value (not key) stored in the map should be
  wrapped in a <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/WeakReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>WeakReference</CODE></A> (by default, strong references
  are used).</TD>
 </TR>
 </TABLE>
 &nbsp;<A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A>
 <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
 <TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
 <TH ALIGN="left"><B>Methods inherited from class java.lang.<A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</A></B></TH>
 </TR>
 <TR BGCOLOR="white" CLASS="TableRowColor">
 <TD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#clone()" title="class or interface in java.lang">clone</A>, <A HREF="http://java.sun.com/javase/6/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://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#finalize()" title="class or interface in java.lang">finalize</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#getClass()" title="class or interface in java.lang">getClass</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#hashCode()" title="class or interface in java.lang">hashCode</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#notify()" title="class or interface in java.lang">notify</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#notifyAll()" title="class or interface in java.lang">notifyAll</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#toString()" title="class or interface in java.lang">toString</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait()" title="class or interface in java.lang">wait</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait(long)" title="class or interface in java.lang">wait</A>, <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait(long, int)" title="class or interface in java.lang">wait</A></CODE></TD>
 </TR>
 </TABLE>
 &nbsp;
 <P>

 <!-- ========= CONSTRUCTOR DETAIL ======== -->

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 <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
 <TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
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 <B>Constructor Detail</B></FONT></TH>
 </TR>
 </TABLE>

 <A NAME="MapMaker()"><!-- --></A><H3>
 MapMaker</H3>
 <PRE>
 public <B>MapMaker</B>()</PRE>
 <DL>
 <DD>Constructs a new <code>MapMaker</code> instance with default settings,
  including strong keys, strong values, and no automatic expiration.
 <P>
 </DL>

 <!-- ============ METHOD DETAIL ========== -->

 <A NAME="method_detail"><!-- --></A>
 <TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
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 <B>Method Detail</B></FONT></TH>
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 </TABLE>

 <A NAME="initialCapacity(int)"><!-- --></A><H3>
 initialCapacity</H3>
 <PRE>
 public <A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A> <B>initialCapacity</B>(int&nbsp;initialCapacity)</PRE>
 <DL>
 <DD>Sets a custom initial capacity (defaults to 16). Resizing this or
  any other kind of hash table is a relatively slow operation, so,
  when possible, it is a good idea to provide estimates of expected
  table sizes.
 <P>
 <DD><DL>

 <DT><B>Throws:</B>
 <DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalArgumentException.html?is-external=true" title="class or interface in java.lang">IllegalArgumentException</A></CODE> - if <code>initialCapacity</code> is
    negative
 <DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalStateException.html?is-external=true" title="class or interface in java.lang">IllegalStateException</A></CODE> - if an initial capacity was already set</DL>
 </DD>
 </DL>
 <HR>

 <A NAME="concurrencyLevel(int)"><!-- --></A><H3>
 concurrencyLevel</H3>
 <PRE>
 public <A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A> <B>concurrencyLevel</B>(int&nbsp;concurrencyLevel)</PRE>
 <DL>
 <DD>Guides the allowed concurrency among update operations. Used as a
  hint for internal sizing. The table is internally partitioned to try
  to permit the indicated number of concurrent updates without
  contention.  Because placement in hash tables is essentially random,
  the actual concurrency will vary. Ideally, you should choose a value
  to accommodate as many threads as will ever concurrently modify the
  table. Using a significantly higher value than you need can waste
  space and time, and a significantly lower value can lead to thread
  contention. But overestimates and underestimates within an order of
  magnitude do not usually have much noticeable impact. A value of one
  is appropriate when it is known that only one thread will modify and
  all others will only read. Defaults to 16.
 <P>
 <DD><DL>

 <DT><B>Throws:</B>
 <DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalArgumentException.html?is-external=true" title="class or interface in java.lang">IllegalArgumentException</A></CODE> - if <code>concurrencyLevel</code> is
      nonpositive
 <DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalStateException.html?is-external=true" title="class or interface in java.lang">IllegalStateException</A></CODE> - if a concurrency level was already set</DL>
 </DD>
 </DL>
 <HR>

 <A NAME="weakKeys()"><!-- --></A><H3>
 weakKeys</H3>
 <PRE>
 public <A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A> <B>weakKeys</B>()</PRE>
 <DL>
 <DD>Specifies that each key (not value) stored in the map should be
  wrapped in a <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/WeakReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>WeakReference</CODE></A> (by default, strong references
  are used).

  <p><b>Note:</b> the map will use identity (<code>==</code>) comparison
  to determine equality of weak keys, which may not behave as you expect.
  For example, storing a key in the map and then attempting a lookup
  using a different but <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#equals(java.lang.Object)" title="class or interface in java.lang"><CODE>equals</CODE></A>-equivalent
  key will always fail.
 <P>
 <DD><DL>

 <DT><B>Throws:</B>
 <DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalStateException.html?is-external=true" title="class or interface in java.lang">IllegalStateException</A></CODE> - if the key strength was already set<DT><B>See Also:</B><DD><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/WeakReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>WeakReference</CODE></A></DL>
 </DD>
 </DL>
 <HR>

 <A NAME="softKeys()"><!-- --></A><H3>
 softKeys</H3>
 <PRE>
 public <A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A> <B>softKeys</B>()</PRE>
 <DL>
 <DD>Specifies that each key (not value) stored in the map should be
  wrapped in a <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/SoftReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>SoftReference</CODE></A> (by default, strong references
  are used).

  <p><b>Note:</b> the map will use identity (<code>==</code>) comparison
  to determine equality of soft keys, which may not behave as you expect.
  For example, storing a key in the map and then attempting a lookup
  using a different but <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true#equals(java.lang.Object)" title="class or interface in java.lang"><CODE>equals</CODE></A>-equivalent
  key will always fail.
 <P>
 <DD><DL>

 <DT><B>Throws:</B>
 <DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalStateException.html?is-external=true" title="class or interface in java.lang">IllegalStateException</A></CODE> - if the key strength was already set<DT><B>See Also:</B><DD><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/SoftReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>SoftReference</CODE></A></DL>
 </DD>
 </DL>
 <HR>

 <A NAME="weakValues()"><!-- --></A><H3>
 weakValues</H3>
 <PRE>
 public <A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A> <B>weakValues</B>()</PRE>
 <DL>
 <DD>Specifies that each value (not key) stored in the map should be
  wrapped in a <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/WeakReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>WeakReference</CODE></A> (by default, strong references
  are used).

  <p>Weak values will be garbage collected once they are weakly
  reachable. This makes them a poor candidate for caching; consider
  <A HREF="../../../../com/google/common/collect/MapMaker.html#softValues()"><CODE>softValues()</CODE></A> instead.

  <p><b>Note:</b> the map will use identity (<code>==</code>) comparison
  to determine equality of weak values. This will notably impact
  the behavior of <A HREF="http://java.sun.com/javase/6/docs/api/java/util/Map.html?is-external=true#containsValue(java.lang.Object)" title="class or interface in java.util"><CODE>containsValue</CODE></A>,
  <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentMap.html?is-external=true#remove(java.lang.Object, java.lang.Object)" title="class or interface in java.util.concurrent"><CODE>remove(Object, Object)</CODE></A>,
  and <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentMap.html?is-external=true#replace(K, V, V)" title="class or interface in java.util.concurrent"><CODE>replace(K, V, V)</CODE></A>.
 <P>
 <DD><DL>

 <DT><B>Throws:</B>
 <DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalStateException.html?is-external=true" title="class or interface in java.lang">IllegalStateException</A></CODE> - if the key strength was already set<DT><B>See Also:</B><DD><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/WeakReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>WeakReference</CODE></A></DL>
 </DD>
 </DL>
 <HR>

 <A NAME="softValues()"><!-- --></A><H3>
 softValues</H3>
 <PRE>
 public <A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A> <B>softValues</B>()</PRE>
 <DL>
 <DD>Specifies that each value (not key) stored in the map should be
  wrapped in a <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/SoftReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>SoftReference</CODE></A> (by default, strong references
  are used).

  <p>Soft values will be garbage collected in response to memory
  demand, and in a least-recently-used manner. This makes them a
  good candidate for caching.

  <p><b>Note:</b> the map will use identity (<code>==</code>) comparison
  to determine equality of soft values. This will notably impact
  the behavior of <A HREF="http://java.sun.com/javase/6/docs/api/java/util/Map.html?is-external=true#containsValue(java.lang.Object)" title="class or interface in java.util"><CODE>containsValue</CODE></A>,
  <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentMap.html?is-external=true#remove(java.lang.Object, java.lang.Object)" title="class or interface in java.util.concurrent"><CODE>remove(Object, Object)</CODE></A>,
  and <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentMap.html?is-external=true#replace(K, V, V)" title="class or interface in java.util.concurrent"><CODE>replace(K, V, V)</CODE></A>.
 <P>
 <DD><DL>

 <DT><B>Throws:</B>
 <DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalStateException.html?is-external=true" title="class or interface in java.lang">IllegalStateException</A></CODE> - if the value strength was already set<DT><B>See Also:</B><DD><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/ref/SoftReference.html?is-external=true" title="class or interface in java.lang.ref"><CODE>SoftReference</CODE></A></DL>
 </DD>
 </DL>
 <HR>

 <A NAME="expiration(long, java.util.concurrent.TimeUnit)"><!-- --></A><H3>
 expiration</H3>
 <PRE>
 public <A HREF="../../../../com/google/common/collect/MapMaker.html" title="class in com.google.common.collect">MapMaker</A> <B>expiration</B>(long&nbsp;duration,
                            <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/TimeUnit.html?is-external=true" title="class or interface in java.util.concurrent">TimeUnit</A>&nbsp;unit)</PRE>
 <DL>
 <DD>Specifies that each entry should be automatically removed from the
  map once a fixed duration has passed since the entry's creation.
 <P>
 <DD><DL>
 <DT><B>Parameters:</B><DD><CODE>duration</CODE> - the length of time after an entry is created that it
      should be automatically removed<DD><CODE>unit</CODE> - the unit that <code>duration</code> is expressed in
 <DT><B>Throws:</B>
 <DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalArgumentException.html?is-external=true" title="class or interface in java.lang">IllegalArgumentException</A></CODE> - if <code>duration</code> is not positive
 <DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalStateException.html?is-external=true" title="class or interface in java.lang">IllegalStateException</A></CODE> - if the expiration time was already set</DL>
 </DD>
 </DL>
 <HR>

 <A NAME="makeMap()"><!-- --></A><H3>
 makeMap</H3>
 <PRE>
 public &lt;K,V&gt; <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentMap.html?is-external=true" title="class or interface in java.util.concurrent">ConcurrentMap</A>&lt;K,V&gt; <B>makeMap</B>()</PRE>
 <DL>
 <DD>Builds the final map, without on-demand computation of values. This method
  does not alter the state of this <code>MapMaker</code> instance, so it can be
  invoked again to create multiple independent maps.
 <P>
 <DD><DL>
 <DT><B>Type Parameters:</B><DD><CODE>K</CODE> - the type of keys to be stored in the returned map<DD><CODE>V</CODE> - the type of values to be stored in the returned map
 <DT><B>Returns:</B><DD>a concurrent map having the requested features</DL>
 </DD>
 </DL>
 <HR>

 <A NAME="makeComputingMap(com.google.common.base.Function)"><!-- --></A><H3>
 makeComputingMap</H3>
 <PRE>
 public &lt;K,V&gt; <A HREF="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ConcurrentMap.html?is-external=true" title="class or interface in java.util.concurrent">ConcurrentMap</A>&lt;K,V&gt; <B>makeComputingMap</B>(<A HREF="../../../../com/google/common/base/Function.html" title="interface in com.google.common.base">Function</A>&lt;? super K,? extends V&gt;&nbsp;computingFunction)</PRE>
 <DL>
 <DD>Builds a map that supports atomic, on-demand computation of values. <A HREF="http://java.sun.com/javase/6/docs/api/java/util/Map.html?is-external=true#get(java.lang.Object)" title="class or interface in java.util"><CODE>Map.get(java.lang.Object)</CODE></A> either returns an already-computed value for the given key,
  atomically computes it using the supplied function, or, if another thread
  is currently computing the value for this key, simply waits for that thread
  to finish and returns its computed value. Note that the function may be
  executed concurrently by multiple threads, but only for distinct keys.

  <p>If an entry's value has not finished computing yet, query methods
  besides <code>get</code> return immediately as if an entry doesn't exist. In
  other words, an entry isn't externally visible until the value's
  computation completes.

  <p><A HREF="http://java.sun.com/javase/6/docs/api/java/util/Map.html?is-external=true#get(java.lang.Object)" title="class or interface in java.util"><CODE>Map.get(java.lang.Object)</CODE></A> on the returned map will never return <code>null</code>. It
  may throw:

  <ul>
  <li><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/NullPointerException.html?is-external=true" title="class or interface in java.lang"><CODE>NullPointerException</CODE></A> if the key is null or the computing
      function returns null
  <li><A HREF="../../../../com/google/common/collect/ComputationException.html" title="class in com.google.common.collect"><CODE>ComputationException</CODE></A> if an exception was thrown by the
      computing function. If that exception is already of type <A HREF="../../../../com/google/common/collect/ComputationException.html" title="class in com.google.common.collect"><CODE>ComputationException</CODE></A>, it is propagated directly; otherwise it is
      wrapped.
  </ul>

  <p><b>Note:</b> Callers of <code>get</code> <i>must</i> ensure that the key
  argument is of type <code>K</code>. The <code>get</code> method accepts <code>Object</code>, so the key type is not checked at compile time. Passing an object
  of a type other than <code>K</code> can result in that object being unsafely
  passed to the computing function as type <code>K</code>, and unsafely stored in
  the map.

  <p>If <A HREF="http://java.sun.com/javase/6/docs/api/java/util/Map.html?is-external=true#put(K, V)" title="class or interface in java.util"><CODE>Map.put(K, V)</CODE></A> is called before a computation completes, other
  threads waiting on the computation will wake up and return the stored
  value. When the computation completes, its new result will overwrite the
  value that was put in the map manually.

  <p>This method does not alter the state of this <code>MapMaker</code> instance,
  so it can be invoked again to create multiple independent maps.
 <P>
 <DD><DL>
 </DL>
 </DD>
 </DL>
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