001: /*
002: * Copyright (c) 2003 The Visigoth Software Society. All rights
003: * reserved.
004: *
005: * Redistribution and use in source and binary forms, with or without
006: * modification, are permitted provided that the following conditions
007: * are met:
008: *
009: * 1. Redistributions of source code must retain the above copyright
010: * notice, this list of conditions and the following disclaimer.
011: *
012: * 2. Redistributions in binary form must reproduce the above copyright
013: * notice, this list of conditions and the following disclaimer in
014: * the documentation and/or other materials provided with the
015: * distribution.
016: *
017: * 3. The end-user documentation included with the redistribution, if
018: * any, must include the following acknowledgement:
019: * "This product includes software developed by the
020: * Visigoth Software Society (http://www.visigoths.org/)."
021: * Alternately, this acknowledgement may appear in the software itself,
022: * if and wherever such third-party acknowledgements normally appear.
023: *
024: * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
025: * project contributors may be used to endorse or promote products derived
026: * from this software without prior written permission. For written
027: * permission, please contact visigoths@visigoths.org.
028: *
029: * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
030: * nor may "FreeMarker" or "Visigoth" appear in their names
031: * without prior written permission of the Visigoth Software Society.
032: *
033: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
034: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
035: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
036: * DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
037: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
038: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
039: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
040: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
041: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
042: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
043: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
044: * SUCH DAMAGE.
045: * ====================================================================
046: *
047: * This software consists of voluntary contributions made by many
048: * individuals on behalf of the Visigoth Software Society. For more
049: * information on the Visigoth Software Society, please see
050: * http://www.visigoths.org/
051: */
052:
053: package freemarker.template.utility;
054:
055: import java.io.Serializable;
056: import java.util.AbstractList;
057: import java.util.AbstractMap;
058: import java.util.Collection;
059: import java.util.Collections;
060: import java.util.List;
061: import java.util.Map;
062: import java.util.Set;
063:
064: /**
065: * Implementation of missing JDK 1.3 collection features for JDK 1.2
066: * @author Attila Szegedi
067: * @version $Id: Collections12.java,v 1.2 2004/11/27 14:49:57 ddekany Exp $
068: */
069: public class Collections12 {
070: public static final Map EMPTY_MAP = new EmptyMap();
071:
072: private Collections12() {
073: }
074:
075: private static final class EmptyMap extends AbstractMap implements
076: Serializable {
077: public int size() {
078: return 0;
079: }
080:
081: public boolean isEmpty() {
082: return true;
083: }
084:
085: public boolean containsKey(Object key) {
086: return false;
087: }
088:
089: public boolean containsValue(Object value) {
090: return false;
091: }
092:
093: public Object get(Object key) {
094: return null;
095: }
096:
097: public Set keySet() {
098: return Collections.EMPTY_SET;
099: }
100:
101: public Collection values() {
102: return Collections.EMPTY_SET;
103: }
104:
105: public Set entrySet() {
106: return Collections.EMPTY_SET;
107: }
108:
109: public boolean equals(Object o) {
110: return (o instanceof Map) && ((Map) o).size() == 0;
111: }
112:
113: public int hashCode() {
114: return 0;
115: }
116: }
117:
118: public static Map singletonMap(Object key, Object value) {
119: return new SingletonMap(key, value);
120: }
121:
122: private static class SingletonMap extends AbstractMap implements
123: Serializable {
124: private final Object k, v;
125:
126: SingletonMap(Object key, Object value) {
127: k = key;
128: v = value;
129: }
130:
131: public int size() {
132: return 1;
133: }
134:
135: public boolean isEmpty() {
136: return false;
137: }
138:
139: public boolean containsKey(Object key) {
140: return eq(key, k);
141: }
142:
143: public boolean containsValue(Object value) {
144: return eq(value, v);
145: }
146:
147: public Object get(Object key) {
148: return (eq(key, k) ? v : null);
149: }
150:
151: private transient Set keySet = null;
152: private transient Set entrySet = null;
153: private transient Collection values = null;
154:
155: public Set keySet() {
156: if (keySet == null)
157: keySet = Collections.singleton(k);
158: return keySet;
159: }
160:
161: public Set entrySet() {
162: if (entrySet == null)
163: entrySet = Collections.singleton(new ImmutableEntry(k,
164: v));
165: return entrySet;
166: }
167:
168: public Collection values() {
169: if (values == null)
170: values = Collections.singleton(v);
171: return values;
172: }
173:
174: private static class ImmutableEntry implements Map.Entry {
175: final Object k;
176: final Object v;
177:
178: ImmutableEntry(Object key, Object value) {
179: k = key;
180: v = value;
181: }
182:
183: public Object getKey() {
184: return k;
185: }
186:
187: public Object getValue() {
188: return v;
189: }
190:
191: public Object setValue(Object value) {
192: throw new UnsupportedOperationException();
193: }
194:
195: public boolean equals(Object o) {
196: if (!(o instanceof Map.Entry))
197: return false;
198: Map.Entry e = (Map.Entry) o;
199: return eq(e.getKey(), k) && eq(e.getValue(), v);
200: }
201:
202: public int hashCode() {
203: return ((k == null ? 0 : k.hashCode()) ^ (v == null ? 0
204: : v.hashCode()));
205: }
206:
207: public String toString() {
208: return k + "=" + v;
209: }
210: }
211: }
212:
213: public static List singletonList(Object o) {
214: return new SingletonList(o);
215: }
216:
217: private static class SingletonList extends AbstractList implements
218: Serializable {
219: private final Object element;
220:
221: SingletonList(Object obj) {
222: element = obj;
223: }
224:
225: public int size() {
226: return 1;
227: }
228:
229: public boolean contains(Object obj) {
230: return eq(obj, element);
231: }
232:
233: public Object get(int index) {
234: if (index != 0)
235: throw new IndexOutOfBoundsException("Index: " + index
236: + ", Size: 1");
237: return element;
238: }
239: }
240:
241: private static boolean eq(Object o1, Object o2) {
242: return (o1 == null ? o2 == null : o1.equals(o2));
243: }
244: }
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