rt/emul/compact/src/main/java/java/util/Dictionary.java
author Jaroslav Tulach <jaroslav.tulach@apidesign.org>
Tue, 26 Feb 2013 16:54:16 +0100
changeset 772 d382dacfd73f
parent 597 emul/compact/src/main/java/java/util/Dictionary.java@ee8a922f4268
permissions -rw-r--r--
Moving modules around so the runtime is under one master pom and can be built without building other modules that are in the repository
     1 /*
     2  * Copyright (c) 1995, 2004, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.  Oracle designates this
     8  * particular file as subject to the "Classpath" exception as provided
     9  * by Oracle in the LICENSE file that accompanied this code.
    10  *
    11  * This code is distributed in the hope that it will be useful, but WITHOUT
    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    14  * version 2 for more details (a copy is included in the LICENSE file that
    15  * accompanied this code).
    16  *
    17  * You should have received a copy of the GNU General Public License version
    18  * 2 along with this work; if not, write to the Free Software Foundation,
    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    20  *
    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    22  * or visit www.oracle.com if you need additional information or have any
    23  * questions.
    24  */
    25 
    26 package java.util;
    27 
    28 /**
    29  * The <code>Dictionary</code> class is the abstract parent of any
    30  * class, such as <code>Hashtable</code>, which maps keys to values.
    31  * Every key and every value is an object. In any one <tt>Dictionary</tt>
    32  * object, every key is associated with at most one value. Given a
    33  * <tt>Dictionary</tt> and a key, the associated element can be looked up.
    34  * Any non-<code>null</code> object can be used as a key and as a value.
    35  * <p>
    36  * As a rule, the <code>equals</code> method should be used by
    37  * implementations of this class to decide if two keys are the same.
    38  * <p>
    39  * <strong>NOTE: This class is obsolete.  New implementations should
    40  * implement the Map interface, rather than extending this class.</strong>
    41  *
    42  * @author  unascribed
    43  * @see     java.util.Map
    44  * @see     java.lang.Object#equals(java.lang.Object)
    45  * @see     java.lang.Object#hashCode()
    46  * @see     java.util.Hashtable
    47  * @since   JDK1.0
    48  */
    49 public abstract
    50 class Dictionary<K,V> {
    51     /**
    52      * Sole constructor.  (For invocation by subclass constructors, typically
    53      * implicit.)
    54      */
    55     public Dictionary() {
    56     }
    57 
    58     /**
    59      * Returns the number of entries (distinct keys) in this dictionary.
    60      *
    61      * @return  the number of keys in this dictionary.
    62      */
    63     abstract public int size();
    64 
    65     /**
    66      * Tests if this dictionary maps no keys to value. The general contract
    67      * for the <tt>isEmpty</tt> method is that the result is true if and only
    68      * if this dictionary contains no entries.
    69      *
    70      * @return  <code>true</code> if this dictionary maps no keys to values;
    71      *          <code>false</code> otherwise.
    72      */
    73     abstract public boolean isEmpty();
    74 
    75     /**
    76      * Returns an enumeration of the keys in this dictionary. The general
    77      * contract for the keys method is that an <tt>Enumeration</tt> object
    78      * is returned that will generate all the keys for which this dictionary
    79      * contains entries.
    80      *
    81      * @return  an enumeration of the keys in this dictionary.
    82      * @see     java.util.Dictionary#elements()
    83      * @see     java.util.Enumeration
    84      */
    85     abstract public Enumeration<K> keys();
    86 
    87     /**
    88      * Returns an enumeration of the values in this dictionary. The general
    89      * contract for the <tt>elements</tt> method is that an
    90      * <tt>Enumeration</tt> is returned that will generate all the elements
    91      * contained in entries in this dictionary.
    92      *
    93      * @return  an enumeration of the values in this dictionary.
    94      * @see     java.util.Dictionary#keys()
    95      * @see     java.util.Enumeration
    96      */
    97     abstract public Enumeration<V> elements();
    98 
    99     /**
   100      * Returns the value to which the key is mapped in this dictionary.
   101      * The general contract for the <tt>isEmpty</tt> method is that if this
   102      * dictionary contains an entry for the specified key, the associated
   103      * value is returned; otherwise, <tt>null</tt> is returned.
   104      *
   105      * @return  the value to which the key is mapped in this dictionary;
   106      * @param   key   a key in this dictionary.
   107      *          <code>null</code> if the key is not mapped to any value in
   108      *          this dictionary.
   109      * @exception NullPointerException if the <tt>key</tt> is <tt>null</tt>.
   110      * @see     java.util.Dictionary#put(java.lang.Object, java.lang.Object)
   111      */
   112     abstract public V get(Object key);
   113 
   114     /**
   115      * Maps the specified <code>key</code> to the specified
   116      * <code>value</code> in this dictionary. Neither the key nor the
   117      * value can be <code>null</code>.
   118      * <p>
   119      * If this dictionary already contains an entry for the specified
   120      * <tt>key</tt>, the value already in this dictionary for that
   121      * <tt>key</tt> is returned, after modifying the entry to contain the
   122      *  new element. <p>If this dictionary does not already have an entry
   123      *  for the specified <tt>key</tt>, an entry is created for the
   124      *  specified <tt>key</tt> and <tt>value</tt>, and <tt>null</tt> is
   125      *  returned.
   126      * <p>
   127      * The <code>value</code> can be retrieved by calling the
   128      * <code>get</code> method with a <code>key</code> that is equal to
   129      * the original <code>key</code>.
   130      *
   131      * @param      key     the hashtable key.
   132      * @param      value   the value.
   133      * @return     the previous value to which the <code>key</code> was mapped
   134      *             in this dictionary, or <code>null</code> if the key did not
   135      *             have a previous mapping.
   136      * @exception  NullPointerException  if the <code>key</code> or
   137      *               <code>value</code> is <code>null</code>.
   138      * @see        java.lang.Object#equals(java.lang.Object)
   139      * @see        java.util.Dictionary#get(java.lang.Object)
   140      */
   141     abstract public V put(K key, V value);
   142 
   143     /**
   144      * Removes the <code>key</code> (and its corresponding
   145      * <code>value</code>) from this dictionary. This method does nothing
   146      * if the <code>key</code> is not in this dictionary.
   147      *
   148      * @param   key   the key that needs to be removed.
   149      * @return  the value to which the <code>key</code> had been mapped in this
   150      *          dictionary, or <code>null</code> if the key did not have a
   151      *          mapping.
   152      * @exception NullPointerException if <tt>key</tt> is <tt>null</tt>.
   153      */
   154     abstract public V remove(Object key);
   155 }