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  Class java.util.Dictionary
</title>
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<h1>
  Class java.util.Dictionary
</h1>
<pre>
<a href="java.lang.Object.html#_top_">java.lang.Object</a>
   |
   +----java.util.Dictionary
</pre>
<hr>
<dl>
  <dt> public abstract class <b>Dictionary</b>
  <dt> extends <a href="java.lang.Object.html#_top_">Object</a>
</dl>
The <code>Dictionary</code> class is the abstract parent of any 
 class, such as <code>Hashtable</code>, which maps keys to values. 
 Any non-<code>null</code> object can be used as a key and as a value.
 <p>
 As a rule, the <code>equals</code> method should be used by 
 implementations of this class to decide if two keys are the same.
<p>
<dl>
    <dt> <b>See Also:</b>
    <dd> <a href="java.lang.Object.html#equals(java.lang.Object)">equals</a>, <a href="java.lang.Object.html#hashCode()">hashCode</a>, <a href="java.util.Hashtable.html#_top_">Hashtable</a>
</dl>
<hr>
<a name="index"></a>
<h2>
  <img src="images/constructor-index.gif" width=275 height=38 alt="Constructor Index">
</h2>
<dl>
  <dt> <img src="images/yellow-ball-small.gif" width=6 height=6 alt=" o ">
	<a href="#Dictionary()"><b>Dictionary</b></a>()
  <dd> 
</dl>
<h2>
  <img src="images/method-index.gif" width=207 height=38 alt="Method Index">
</h2>
<dl>
  <dt> <img src="images/red-ball-small.gif" width=6 height=6 alt=" o ">
	<a href="#elements()"><b>elements</b></a>()
  <dd>  Returns an enumeration of the values in this dictionary.
  <dt> <img src="images/red-ball-small.gif" width=6 height=6 alt=" o ">
	<a href="#get(java.lang.Object)"><b>get</b></a>(Object)
  <dd>  Returns the value to which the key is mapped in this dictionary.
  <dt> <img src="images/red-ball-small.gif" width=6 height=6 alt=" o ">
	<a href="#isEmpty()"><b>isEmpty</b></a>()
  <dd>  Tests if this dictionary maps no keys to value.
  <dt> <img src="images/red-ball-small.gif" width=6 height=6 alt=" o ">
	<a href="#keys()"><b>keys</b></a>()
  <dd>  Returns an enumeration of the keys in this dictionary.
  <dt> <img src="images/red-ball-small.gif" width=6 height=6 alt=" o ">
	<a href="#put(java.lang.Object, java.lang.Object)"><b>put</b></a>(Object, Object)
  <dd>  Maps the specified <code>key</code> to the specified 
 <code>value</code> in this dictionary.
  <dt> <img src="images/red-ball-small.gif" width=6 height=6 alt=" o ">
	<a href="#remove(java.lang.Object)"><b>remove</b></a>(Object)
  <dd>  Removes the <code>key</code> (and its corresponding 
 <code>value</code>) from this dictionary.
  <dt> <img src="images/red-ball-small.gif" width=6 height=6 alt=" o ">
	<a href="#size()"><b>size</b></a>()
  <dd>  Returns the number of keys in this dictionary.
</dl>
<a name="constructors"></a>
<h2>
  <img src="images/constructors.gif" width=231 height=38 alt="Constructors">
</h2>
<a name="Dictionary"></a>
<a name="Dictionary()"><img src="images/yellow-ball.gif" width=12 height=12 alt=" o "></a>
<b>Dictionary</b>
<pre>
 public Dictionary()
</pre>
<a name="methods"></a>
<h2>
  <img src="images/methods.gif" width=151 height=38 alt="Methods">
</h2>
<a name="size()"><img src="images/red-ball.gif" width=12 height=12 alt=" o "></a>
<a name="size"><b>size</b></a>
<pre>
 public abstract int size()
</pre>
<dl>
  <dd> Returns the number of keys in this dictionary.
<p>
  <dd><dl>
    <dt> <b>Returns:</b>
    <dd> the number of keys in this dictionary.
  </dl></dd>
</dl>
<a name="isEmpty()"><img src="images/red-ball.gif" width=12 height=12 alt=" o "></a>
<a name="isEmpty"><b>isEmpty</b></a>
<pre>
 public abstract boolean isEmpty()
</pre>
<dl>
  <dd> Tests if this dictionary maps no keys to value.
<p>
  <dd><dl>
    <dt> <b>Returns:</b>
    <dd> <code>true</code> if this dictionary maps no keys to values;
          <code>false</code> otherwise.
  </dl></dd>
</dl>
<a name="keys()"><img src="images/red-ball.gif" width=12 height=12 alt=" o "></a>
<a name="keys"><b>keys</b></a>
<pre>
 public abstract <a href="java.util.Enumeration.html#_top_">Enumeration</a> keys()
</pre>
<dl>
  <dd> Returns an enumeration of the keys in this dictionary.
<p>
  <dd><dl>
    <dt> <b>Returns:</b>
    <dd> an enumeration of the keys in this dictionary.
    <dt> <b>See Also:</b>
    <dd> <a href="#elements()">elements</a>, <a href="java.util.Enumeration.html#_top_">Enumeration</a>
  </dl></dd>
</dl>
<a name="elements()"><img src="images/red-ball.gif" width=12 height=12 alt=" o "></a>
<a name="elements"><b>elements</b></a>
<pre>
 public abstract <a href="java.util.Enumeration.html#_top_">Enumeration</a> elements()
</pre>
<dl>
  <dd> Returns an enumeration of the values in this dictionary.
 the Enumeration methods on the returned object to fetch the elements
 sequentially.
<p>
  <dd><dl>
    <dt> <b>Returns:</b>
    <dd> an enumeration of the values in this dictionary.
    <dt> <b>See Also:</b>
    <dd> <a href="#keys()">keys</a>, <a href="java.util.Enumeration.html#_top_">Enumeration</a>
  </dl></dd>
</dl>
<a name="get(java.lang.Object)"><img src="images/red-ball.gif" width=12 height=12 alt=" o "></a>
<a name="get"><b>get</b></a>
<pre>
 public abstract <a href="java.lang.Object.html#_top_">Object</a> get(<a href="java.lang.Object.html#_top_">Object</a> key)
</pre>
<dl>
  <dd> Returns the value to which the key is mapped in this dictionary.
<p>
  <dd><dl>
    <dt> <b>Parameters:</b>
    <dd> key - a key in this dictionary.
          <code>null</code> if the key is not mapped to any value in
          this dictionary.
    <dt> <b>Returns:</b>
    <dd> the value to which the key is mapped in this dictionary;
    <dt> <b>See Also:</b>
    <dd> <a href="#put(java.lang.Object, java.lang.Object)">put</a>
  </dl></dd>
</dl>
<a name="put(java.lang.Object, java.lang.Object)"><img src="images/red-ball.gif" width=12 height=12 alt=" o "></a>
<a name="put"><b>put</b></a>
<pre>
 public abstract <a href="java.lang.Object.html#_top_">Object</a> put(<a href="java.lang.Object.html#_top_">Object</a> key,
                            <a href="java.lang.Object.html#_top_">Object</a> value)
</pre>
<dl>
  <dd> Maps the specified <code>key</code> to the specified 
 <code>value</code> in this dictionary. Neither the key nor the 
 value can be <code>null</code>.
 <p>
 The <code>value</code> can be retrieved by calling the 
 <code>get</code> method with a <code>key</code> that is equal to 
 the original <code>key</code>.
<p>
  <dd><dl>
    <dt> <b>Parameters:</b>
    <dd> key - the hashtable key.
    <dd> value - the value.
    <dt> <b>Returns:</b>
    <dd> the previous value to which the <code>key</code> was mapped
             in this dictionary, or <code>null</code> if the key did not
             have a previous mapping.
    <dt> <b>Throws:</b> <a href="java.lang.NullPointerException.html#_top_">NullPointerException</a>
    <dd> if the <code>key</code> or
               <code>value</code> is <code>null</code>.
    <dt> <b>See Also:</b>
    <dd> <a href="java.lang.Object.html#equals(java.lang.Object)">equals</a>, <a href="#get(java.lang.Object)">get</a>
  </dl></dd>
</dl>
<a name="remove(java.lang.Object)"><img src="images/red-ball.gif" width=12 height=12 alt=" o "></a>
<a name="remove"><b>remove</b></a>
<pre>
 public abstract <a href="java.lang.Object.html#_top_">Object</a> remove(<a href="java.lang.Object.html#_top_">Object</a> key)
</pre>
<dl>
  <dd> Removes the <code>key</code> (and its corresponding 
 <code>value</code>) from this dictionary. This method does nothing 
 if the <code>key</code> is not in this dictionary.
<p>
  <dd><dl>
    <dt> <b>Parameters:</b>
    <dd> key - the key that needs to be removed.
    <dt> <b>Returns:</b>
    <dd> the value to which the <code>key</code> had been mapped in this
          dictionary, or <code>null</code> if the key did not have a
          mapping.
  </dl></dd>
</dl>
<hr>
<pre>
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