StoredSortedEntrySet


1   /*-
2    * See the file LICENSE for redistribution information.
3    *
4    * Copyright (c) 2000,2006 Oracle.  All rights reserved.
5    *
6    * $Id: StoredSortedEntrySet.java,v 1.24 2006/10/30 21:14:10 bostic Exp $
7    */
8   
9   package com.sleepycat.collections;
10  
11  import java.util.Comparator  ;
12  import java.util.Map  ;
13  import java.util.SortedSet  ;
14  
15  /**
16   * The SortedSet returned by Map.entrySet().  This class may not be
17   * instantiated directly.  Contrary to what is stated by {@link Map#entrySet}
18   * this class does support the {@link #add} and {@link #addAll} methods.
19   *
20   * <p>The {@link java.util.Map.Entry#setValue} method of the Map.Entry objects
21   * that are returned by this class and its iterators behaves just as the {@link
22   * StoredIterator#set} method does.</p>
23   *
24   * <p>In addition to the standard SortedSet methods, this class provides the
25   * following methods for stored sorted sets only.  Note that the use of these
26   * methods is not compatible with the standard Java collections interface.</p>
27   * <ul>
28   * <li>{@link #headSet(Object, boolean)}</li>
29   * <li>{@link #tailSet(Object, boolean)}</li>
30   * <li>{@link #subSet(Object, boolean, Object, boolean)}</li>
31   * </ul>
32   *
33   * @author Mark Hayes
34   */
35  public class StoredSortedEntrySet extends StoredEntrySet implements SortedSet   {
36  
37      StoredSortedEntrySet(DataView mapView) {
38  
39          super(mapView);
40      }
41  
42      /**
43       * Returns null since comparators are not supported.  The natural ordering
44       * of a stored collection is data byte order, whether the data classes
45       * implement the {@link java.lang.Comparable} interface or not.
46       * This method does not conform to the {@link SortedSet#comparator}
47       * interface.
48       *
49       * @return null.
50       */
51      public Comparator   comparator() {
52  
53          return null;
54      }
55  
56      /**
57       * Returns the first (lowest) element currently in this sorted set.
58       * This method conforms to the {@link SortedSet#first} interface.
59       *
60       * @return the first element.
61       *
62       * @throws RuntimeExceptionWrapper if a {@link
63       * com.sleepycat.je.DatabaseException} is thrown.
64       */
65      public Object   first() {
66  
67          return getFirstOrLast(true);
68      }
69  
70      /**
71       * Returns the last (highest) element currently in this sorted set.
72       * This method conforms to the {@link SortedSet#last} interface.
73       *
74       * @return the last element.
75       *
76       * @throws RuntimeExceptionWrapper if a {@link
77       * com.sleepycat.je.DatabaseException} is thrown.
78       */
79      public Object   last() {
80  
81          return getFirstOrLast(false);
82      }
83  
84      /**
85       * Returns a view of the portion of this sorted set whose elements are
86       * strictly less than toMapEntry.
87       * This method conforms to the {@link SortedSet#headSet} interface.
88       *
89       * <p>Note that the return value is a StoredCollection and must be treated
90       * as such; for example, its iterators must be explicitly closed.</p>
91       *
92       * @param toMapEntry the upper bound.
93       *
94       * @return the subset.
95       *
96       * @throws RuntimeExceptionWrapper if a {@link
97       * com.sleepycat.je.DatabaseException} is thrown.
98       */
99      public SortedSet   headSet(Object   toMapEntry) {
100 
101         return subSet(null, false, toMapEntry, false);
102     }
103 
104     /**
105      * Returns a view of the portion of this sorted set whose elements are
106      * strictly less than toMapEntry, optionally including toMapEntry.
107      * This method does not exist in the standard {@link SortedSet} interface.
108      *
109      * <p>Note that the return value is a StoredCollection and must be treated
110      * as such; for example, its iterators must be explicitly closed.</p>
111      *
112      * @param toMapEntry is the upper bound.
113      *
114      * @param toInclusive is true to include toMapEntry.
115      *
116      * @return the subset.
117      *
118      * @throws RuntimeExceptionWrapper if a {@link
119      * com.sleepycat.je.DatabaseException} is thrown.
120      */
121     public SortedSet   headSet(Object   toMapEntry, boolean toInclusive) {
122 
123         return subSet(null, false, toMapEntry, toInclusive);
124     }
125 
126     /**
127      * Returns a view of the portion of this sorted set whose elements are
128      * greater than or equal to fromMapEntry.
129      * This method conforms to the {@link SortedSet#tailSet} interface.
130      *
131      * <p>Note that the return value is a StoredCollection and must be treated
132      * as such; for example, its iterators must be explicitly closed.</p>
133      *
134      * @param fromMapEntry is the lower bound.
135      *
136      * @return the subset.
137      *
138      * @throws RuntimeExceptionWrapper if a {@link
139      * com.sleepycat.je.DatabaseException} is thrown.
140      */
141     public SortedSet   tailSet(Object   fromMapEntry) {
142 
143         return subSet(fromMapEntry, true, null, false);
144     }
145 
146     /**
147      * Returns a view of the portion of this sorted set whose elements are
148      * strictly greater than fromMapEntry, optionally including fromMapEntry.
149      * This method does not exist in the standard {@link SortedSet} interface.
150      *
151      * <p>Note that the return value is a StoredCollection and must be treated
152      * as such; for example, its iterators must be explicitly closed.</p>
153      *
154      * @param fromMapEntry is the lower bound.
155      *
156      * @param fromInclusive is true to include fromMapEntry.
157      *
158      * @return the subset.
159      *
160      * @throws RuntimeExceptionWrapper if a {@link
161      * com.sleepycat.je.DatabaseException} is thrown.
162      */
163     public SortedSet   tailSet(Object   fromMapEntry, boolean fromInclusive) {
164 
165         return subSet(fromMapEntry, fromInclusive, null, false);
166     }
167 
168     /**
169      * Returns a view of the portion of this sorted set whose elements range
170      * from fromMapEntry, inclusive, to toMapEntry, exclusive.
171      * This method conforms to the {@link SortedSet#subSet} interface.
172      *
173      * <p>Note that the return value is a StoredCollection and must be treated
174      * as such; for example, its iterators must be explicitly closed.</p>
175      *
176      * @param fromMapEntry is the lower bound.
177      *
178      * @param toMapEntry is the upper bound.
179      *
180      * @return the subset.
181      *
182      * @throws RuntimeExceptionWrapper if a {@link
183      * com.sleepycat.je.DatabaseException} is thrown.
184      */
185     public SortedSet   subSet(Object   fromMapEntry, Object   toMapEntry) {
186 
187         return subSet(fromMapEntry, true, toMapEntry, false);
188     }
189 
190     /**
191      * Returns a view of the portion of this sorted set whose elements are
192      * strictly greater than fromMapEntry and strictly less than toMapEntry,
193      * optionally including fromMapEntry and toMapEntry.
194      * This method does not exist in the standard {@link SortedSet} interface.
195      *
196      * <p>Note that the return value is a StoredCollection and must be treated
197      * as such; for example, its iterators must be explicitly closed.</p>
198      *
199      * @param fromMapEntry is the lower bound.
200      *
201      * @param fromInclusive is true to include fromMapEntry.
202      *
203      * @param toMapEntry is the upper bound.
204      *
205      * @param toInclusive is true to include toMapEntry.
206      *
207      * @return the subset.
208      *
209      * @throws RuntimeExceptionWrapper if a {@link
210      * com.sleepycat.je.DatabaseException} is thrown.
211      */
212     public SortedSet   subSet(Object   fromMapEntry, boolean fromInclusive,
213                             Object   toMapEntry, boolean toInclusive) {
214 
215         Object   fromKey = (fromMapEntry != null) ?
216             ((Map.Entry  ) fromMapEntry).getKey() : null;
217         Object   toKey = (toMapEntry != null) ?
218             ((Map.Entry  ) toMapEntry).getKey() : null;
219         try {
220             return new StoredSortedEntrySet(
221                view.subView(fromKey, fromInclusive, toKey, toInclusive, null));
222         } catch (Exception   e) {
223             throw StoredContainer.convertException(e);
224         }
225     }
226 }
227
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags