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 collection, if it is present (optional operation).</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;boolean</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../java/util/Collection.html#removeAll(java.util.Collection)">removeAll</A></B>(<A HREF="../../java/util/Collection.html">Collection</A>&nbsp;c)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Removes all this collection's elements that are also contained in the
 specified collection (optional operation).</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;boolean</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../java/util/Collection.html#retainAll(java.util.Collection)">retainAll</A></B>(<A HREF="../../java/util/Collection.html">Collection</A>&nbsp;c)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Retains only the elements in this collection that are contained in the
 specified collection (optional operation).</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../java/util/Collection.html#size()">size</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Returns the number of elements in this collection.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../java/lang/Object.html">Object</A>[]</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../java/util/Collection.html#toArray()">toArray</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Returns an array containing all of the elements in this collection.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../java/lang/Object.html">Object</A>[]</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../java/util/Collection.html#toArray(java.lang.Object[])">toArray</A></B>(<A HREF="../../java/lang/Object.html">Object</A>[]&nbsp;a)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Returns an array containing all of the elements in this collection
 whose runtime type is that of the specified array.</TD>
</TR>
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<B>Method Detail</B></FONT></TD>
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<A NAME="size()"><!-- --></A><H3>
size</H3>
<PRE>
public int <B>size</B>()</PRE>
<DL>
<DD>Returns the number of elements in this collection.  If this collection
 contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
 <tt>Integer.MAX_VALUE</tt>.<DD><DL>
<DT><B>Returns:</B><DD>the number of elements in this collection</DL>
</DD>
</DL>
<HR>

<A NAME="isEmpty()"><!-- --></A><H3>
isEmpty</H3>
<PRE>
public boolean <B>isEmpty</B>()</PRE>
<DL>
<DD>Returns <tt>true</tt> if this collection contains no elements.<DD><DL>
<DT><B>Returns:</B><DD><tt>true</tt> if this collection contains no elements</DL>
</DD>
</DL>
<HR>

<A NAME="contains(java.lang.Object)"><!-- --></A><H3>
contains</H3>
<PRE>
public boolean <B>contains</B>(<A HREF="../../java/lang/Object.html">Object</A>&nbsp;o)</PRE>
<DL>
<DD>Returns <tt>true</tt> if this collection contains the specified
 element.  More formally, returns <tt>true</tt> if and only if this
 collection contains at least one element <tt>e</tt> such that
 <tt>(o==null ? e==null : o.equals(e))</tt>.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>o</CODE> - element whose presence in this collection is to be tested.<DT><B>Returns:</B><DD><tt>true</tt> if this collection contains the specified
         element</DL>
</DD>
</DL>
<HR>

<A NAME="iterator()"><!-- --></A><H3>
iterator</H3>
<PRE>
public <A HREF="../../java/util/Iterator.html">Iterator</A> <B>iterator</B>()</PRE>
<DL>
<DD>Returns an iterator over the elements in this collection.  There are no
 guarantees concerning the order in which the elements are returned
 (unless this collection is an instance of some class that provides a
 guarantee).<DD><DL>
<DT><B>Returns:</B><DD>an <tt>Iterator</tt> over the elements in this collection</DL>
</DD>
</DL>
<HR>

<A NAME="toArray()"><!-- --></A><H3>
toArray</H3>
<PRE>
public <A HREF="../../java/lang/Object.html">Object</A>[] <B>toArray</B>()</PRE>
<DL>
<DD>Returns an array containing all of the elements in this collection.  If
 the collection makes any guarantees as to what order its elements are
 returned by its iterator, this method must return the elements in the
 same order.<p>

 The returned array will be "safe" in that no references to it are
 maintained by this collection.  (In other words, this method must
 allocate a new array even if this collection is backed by an array).
 The caller is thus free to modify the returned array.<p>

 This method acts as bridge between array-based and collection-based
 APIs.<DD><DL>
<DT><B>Returns:</B><DD>an array containing all of the elements in this collection</DL>
</DD>
</DL>
<HR>

<A NAME="toArray(java.lang.Object[])"><!-- --></A><H3>
toArray</H3>
<PRE>
public <A HREF="../../java/lang/Object.html">Object</A>[] <B>toArray</B>(<A HREF="../../java/lang/Object.html">Object</A>[]&nbsp;a)</PRE>
<DL>
<DD>Returns an array containing all of the elements in this collection
 whose runtime type is that of the specified array.  If the collection
 fits in the specified array, it is returned therein.  Otherwise, a new
 array is allocated with the runtime type of the specified array and the
 size of this collection.<p>

 If this collection fits in the specified array with room to spare
 (i.e., the array has more elements than this collection), the element
 in the array immediately following the end of the collection is set to
 <tt>null</tt>.  This is useful in determining the length of this
 collection <i>only</i> if the caller knows that this collection does
 not contain any <tt>null</tt> elements.)<p>

 If this collection makes any guarantees as to what order its elements
 are returned by its iterator, this method must return the elements in
 the same order.<p>

 Like the <tt>toArray</tt> method, this method acts as bridge between
 array-based and collection-based APIs.  Further, this method allows
 precise control over the runtime type of the output array, and may,
 under certain circumstances, be used to save allocation costs<p>

 Suppose <tt>l</tt> is a <tt>List</tt> known to contain only strings.
 The following code can be used to dump the list into a newly allocated
 array of <tt>String</tt>:

 <pre>
     String[] x = (String[]) v.toArray(new String[0]);
 </pre><p>

 Note that <tt>toArray(new Object[0])</tt> is identical in function to
 <tt>toArray()</tt>.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>a</CODE> - the array into which the elements of this collection are to be
        stored, if it is big enough; otherwise, a new array of the same
        runtime type is allocated for this purpose.<DT><B>Returns:</B><DD>an array containing the elements of this collection<DT><B>Throws:</B><DD><CODE><A HREF="../../java/lang/ArrayStoreException.html">ArrayStoreException</A></CODE> - the runtime type of the specified array is
         not a supertype of the runtime type of every element in this
         collection.</DL>
</DD>
</DL>
<HR>

<A NAME="add(java.lang.Object)"><!-- --></A><H3>
add</H3>
<PRE>
public boolean <B>add</B>(<A HREF="../../java/lang/Object.html">Object</A>&nbsp;o)</PRE>
<DL>
<DD>Ensures that this collection contains the specified element (optional
 operation).  Returns <tt>true</tt> if this collection changed as a
 result of the call.  (Returns <tt>false</tt> if this collection does
 not permit duplicates and already contains the specified element.)<p>

 Collections that support this operation may place limitations on what
 elements may be added to this collection.  In particular, some
 collections will refuse to add <tt>null</tt> elements, and others will
 impose restrictions on the type of elements that may be added.
 Collection classes should clearly specify in their documentation any
 restrictions on what elements may be added.<p>

 If a collection refuses to add a particular element for any reason
 other than that it already contains the element, it <i>must</i> throw
 an exception (rather than returning <tt>false</tt>).  This preserves
 the invariant that a collection always contains the specified element
 after this call returns.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>o</CODE> - element whose presence in this collection is to be ensured.<DT><B>Returns:</B><DD><tt>true</tt> if this collection changed as a result of the
         call<DT><B>Throws:</B><DD><CODE><A HREF="../../java/lang/UnsupportedOperationException.html">UnsupportedOperationException</A></CODE> - add is not supported by this
         collection.<DD><CODE><A HREF="../../java/lang/ClassCastException.html">ClassCastException</A></CODE> - class of the specified element prevents it
         from being added to this collection.<DD><CODE><A HREF="../../java/lang/IllegalArgumentException.html">IllegalArgumentException</A></CODE> - some aspect of this element prevents
          it from being added to this collection.</DL>