1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/rt/emul/compact/src/main/java/java/util/AbstractMap.java Tue Feb 26 16:54:16 2013 +0100
1.3 @@ -0,0 +1,822 @@
1.4 +/*
1.5 + * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation. Oracle designates this
1.11 + * particular file as subject to the "Classpath" exception as provided
1.12 + * by Oracle in the LICENSE file that accompanied this code.
1.13 + *
1.14 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.15 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.16 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.17 + * version 2 for more details (a copy is included in the LICENSE file that
1.18 + * accompanied this code).
1.19 + *
1.20 + * You should have received a copy of the GNU General Public License version
1.21 + * 2 along with this work; if not, write to the Free Software Foundation,
1.22 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.23 + *
1.24 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.25 + * or visit www.oracle.com if you need additional information or have any
1.26 + * questions.
1.27 + */
1.28 +
1.29 +package java.util;
1.30 +import java.util.Map.Entry;
1.31 +
1.32 +/**
1.33 + * This class provides a skeletal implementation of the <tt>Map</tt>
1.34 + * interface, to minimize the effort required to implement this interface.
1.35 + *
1.36 + * <p>To implement an unmodifiable map, the programmer needs only to extend this
1.37 + * class and provide an implementation for the <tt>entrySet</tt> method, which
1.38 + * returns a set-view of the map's mappings. Typically, the returned set
1.39 + * will, in turn, be implemented atop <tt>AbstractSet</tt>. This set should
1.40 + * not support the <tt>add</tt> or <tt>remove</tt> methods, and its iterator
1.41 + * should not support the <tt>remove</tt> method.
1.42 + *
1.43 + * <p>To implement a modifiable map, the programmer must additionally override
1.44 + * this class's <tt>put</tt> method (which otherwise throws an
1.45 + * <tt>UnsupportedOperationException</tt>), and the iterator returned by
1.46 + * <tt>entrySet().iterator()</tt> must additionally implement its
1.47 + * <tt>remove</tt> method.
1.48 + *
1.49 + * <p>The programmer should generally provide a void (no argument) and map
1.50 + * constructor, as per the recommendation in the <tt>Map</tt> interface
1.51 + * specification.
1.52 + *
1.53 + * <p>The documentation for each non-abstract method in this class describes its
1.54 + * implementation in detail. Each of these methods may be overridden if the
1.55 + * map being implemented admits a more efficient implementation.
1.56 + *
1.57 + * <p>This class is a member of the
1.58 + * <a href="{@docRoot}/../technotes/guides/collections/index.html">
1.59 + * Java Collections Framework</a>.
1.60 + *
1.61 + * @param <K> the type of keys maintained by this map
1.62 + * @param <V> the type of mapped values
1.63 + *
1.64 + * @author Josh Bloch
1.65 + * @author Neal Gafter
1.66 + * @see Map
1.67 + * @see Collection
1.68 + * @since 1.2
1.69 + */
1.70 +
1.71 +public abstract class AbstractMap<K,V> implements Map<K,V> {
1.72 + /**
1.73 + * Sole constructor. (For invocation by subclass constructors, typically
1.74 + * implicit.)
1.75 + */
1.76 + protected AbstractMap() {
1.77 + }
1.78 +
1.79 + // Query Operations
1.80 +
1.81 + /**
1.82 + * {@inheritDoc}
1.83 + *
1.84 + * <p>This implementation returns <tt>entrySet().size()</tt>.
1.85 + */
1.86 + public int size() {
1.87 + return entrySet().size();
1.88 + }
1.89 +
1.90 + /**
1.91 + * {@inheritDoc}
1.92 + *
1.93 + * <p>This implementation returns <tt>size() == 0</tt>.
1.94 + */
1.95 + public boolean isEmpty() {
1.96 + return size() == 0;
1.97 + }
1.98 +
1.99 + /**
1.100 + * {@inheritDoc}
1.101 + *
1.102 + * <p>This implementation iterates over <tt>entrySet()</tt> searching
1.103 + * for an entry with the specified value. If such an entry is found,
1.104 + * <tt>true</tt> is returned. If the iteration terminates without
1.105 + * finding such an entry, <tt>false</tt> is returned. Note that this
1.106 + * implementation requires linear time in the size of the map.
1.107 + *
1.108 + * @throws ClassCastException {@inheritDoc}
1.109 + * @throws NullPointerException {@inheritDoc}
1.110 + */
1.111 + public boolean containsValue(Object value) {
1.112 + Iterator<Entry<K,V>> i = entrySet().iterator();
1.113 + if (value==null) {
1.114 + while (i.hasNext()) {
1.115 + Entry<K,V> e = i.next();
1.116 + if (e.getValue()==null)
1.117 + return true;
1.118 + }
1.119 + } else {
1.120 + while (i.hasNext()) {
1.121 + Entry<K,V> e = i.next();
1.122 + if (value.equals(e.getValue()))
1.123 + return true;
1.124 + }
1.125 + }
1.126 + return false;
1.127 + }
1.128 +
1.129 + /**
1.130 + * {@inheritDoc}
1.131 + *
1.132 + * <p>This implementation iterates over <tt>entrySet()</tt> searching
1.133 + * for an entry with the specified key. If such an entry is found,
1.134 + * <tt>true</tt> is returned. If the iteration terminates without
1.135 + * finding such an entry, <tt>false</tt> is returned. Note that this
1.136 + * implementation requires linear time in the size of the map; many
1.137 + * implementations will override this method.
1.138 + *
1.139 + * @throws ClassCastException {@inheritDoc}
1.140 + * @throws NullPointerException {@inheritDoc}
1.141 + */
1.142 + public boolean containsKey(Object key) {
1.143 + Iterator<Map.Entry<K,V>> i = entrySet().iterator();
1.144 + if (key==null) {
1.145 + while (i.hasNext()) {
1.146 + Entry<K,V> e = i.next();
1.147 + if (e.getKey()==null)
1.148 + return true;
1.149 + }
1.150 + } else {
1.151 + while (i.hasNext()) {
1.152 + Entry<K,V> e = i.next();
1.153 + if (key.equals(e.getKey()))
1.154 + return true;
1.155 + }
1.156 + }
1.157 + return false;
1.158 + }
1.159 +
1.160 + /**
1.161 + * {@inheritDoc}
1.162 + *
1.163 + * <p>This implementation iterates over <tt>entrySet()</tt> searching
1.164 + * for an entry with the specified key. If such an entry is found,
1.165 + * the entry's value is returned. If the iteration terminates without
1.166 + * finding such an entry, <tt>null</tt> is returned. Note that this
1.167 + * implementation requires linear time in the size of the map; many
1.168 + * implementations will override this method.
1.169 + *
1.170 + * @throws ClassCastException {@inheritDoc}
1.171 + * @throws NullPointerException {@inheritDoc}
1.172 + */
1.173 + public V get(Object key) {
1.174 + Iterator<Entry<K,V>> i = entrySet().iterator();
1.175 + if (key==null) {
1.176 + while (i.hasNext()) {
1.177 + Entry<K,V> e = i.next();
1.178 + if (e.getKey()==null)
1.179 + return e.getValue();
1.180 + }
1.181 + } else {
1.182 + while (i.hasNext()) {
1.183 + Entry<K,V> e = i.next();
1.184 + if (key.equals(e.getKey()))
1.185 + return e.getValue();
1.186 + }
1.187 + }
1.188 + return null;
1.189 + }
1.190 +
1.191 +
1.192 + // Modification Operations
1.193 +
1.194 + /**
1.195 + * {@inheritDoc}
1.196 + *
1.197 + * <p>This implementation always throws an
1.198 + * <tt>UnsupportedOperationException</tt>.
1.199 + *
1.200 + * @throws UnsupportedOperationException {@inheritDoc}
1.201 + * @throws ClassCastException {@inheritDoc}
1.202 + * @throws NullPointerException {@inheritDoc}
1.203 + * @throws IllegalArgumentException {@inheritDoc}
1.204 + */
1.205 + public V put(K key, V value) {
1.206 + throw new UnsupportedOperationException();
1.207 + }
1.208 +
1.209 + /**
1.210 + * {@inheritDoc}
1.211 + *
1.212 + * <p>This implementation iterates over <tt>entrySet()</tt> searching for an
1.213 + * entry with the specified key. If such an entry is found, its value is
1.214 + * obtained with its <tt>getValue</tt> operation, the entry is removed
1.215 + * from the collection (and the backing map) with the iterator's
1.216 + * <tt>remove</tt> operation, and the saved value is returned. If the
1.217 + * iteration terminates without finding such an entry, <tt>null</tt> is
1.218 + * returned. Note that this implementation requires linear time in the
1.219 + * size of the map; many implementations will override this method.
1.220 + *
1.221 + * <p>Note that this implementation throws an
1.222 + * <tt>UnsupportedOperationException</tt> if the <tt>entrySet</tt>
1.223 + * iterator does not support the <tt>remove</tt> method and this map
1.224 + * contains a mapping for the specified key.
1.225 + *
1.226 + * @throws UnsupportedOperationException {@inheritDoc}
1.227 + * @throws ClassCastException {@inheritDoc}
1.228 + * @throws NullPointerException {@inheritDoc}
1.229 + */
1.230 + public V remove(Object key) {
1.231 + Iterator<Entry<K,V>> i = entrySet().iterator();
1.232 + Entry<K,V> correctEntry = null;
1.233 + if (key==null) {
1.234 + while (correctEntry==null && i.hasNext()) {
1.235 + Entry<K,V> e = i.next();
1.236 + if (e.getKey()==null)
1.237 + correctEntry = e;
1.238 + }
1.239 + } else {
1.240 + while (correctEntry==null && i.hasNext()) {
1.241 + Entry<K,V> e = i.next();
1.242 + if (key.equals(e.getKey()))
1.243 + correctEntry = e;
1.244 + }
1.245 + }
1.246 +
1.247 + V oldValue = null;
1.248 + if (correctEntry !=null) {
1.249 + oldValue = correctEntry.getValue();
1.250 + i.remove();
1.251 + }
1.252 + return oldValue;
1.253 + }
1.254 +
1.255 +
1.256 + // Bulk Operations
1.257 +
1.258 + /**
1.259 + * {@inheritDoc}
1.260 + *
1.261 + * <p>This implementation iterates over the specified map's
1.262 + * <tt>entrySet()</tt> collection, and calls this map's <tt>put</tt>
1.263 + * operation once for each entry returned by the iteration.
1.264 + *
1.265 + * <p>Note that this implementation throws an
1.266 + * <tt>UnsupportedOperationException</tt> if this map does not support
1.267 + * the <tt>put</tt> operation and the specified map is nonempty.
1.268 + *
1.269 + * @throws UnsupportedOperationException {@inheritDoc}
1.270 + * @throws ClassCastException {@inheritDoc}
1.271 + * @throws NullPointerException {@inheritDoc}
1.272 + * @throws IllegalArgumentException {@inheritDoc}
1.273 + */
1.274 + public void putAll(Map<? extends K, ? extends V> m) {
1.275 + for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1.276 + put(e.getKey(), e.getValue());
1.277 + }
1.278 +
1.279 + /**
1.280 + * {@inheritDoc}
1.281 + *
1.282 + * <p>This implementation calls <tt>entrySet().clear()</tt>.
1.283 + *
1.284 + * <p>Note that this implementation throws an
1.285 + * <tt>UnsupportedOperationException</tt> if the <tt>entrySet</tt>
1.286 + * does not support the <tt>clear</tt> operation.
1.287 + *
1.288 + * @throws UnsupportedOperationException {@inheritDoc}
1.289 + */
1.290 + public void clear() {
1.291 + entrySet().clear();
1.292 + }
1.293 +
1.294 +
1.295 + // Views
1.296 +
1.297 + /**
1.298 + * Each of these fields are initialized to contain an instance of the
1.299 + * appropriate view the first time this view is requested. The views are
1.300 + * stateless, so there's no reason to create more than one of each.
1.301 + */
1.302 + transient volatile Set<K> keySet = null;
1.303 + transient volatile Collection<V> values = null;
1.304 +
1.305 + /**
1.306 + * {@inheritDoc}
1.307 + *
1.308 + * <p>This implementation returns a set that subclasses {@link AbstractSet}.
1.309 + * The subclass's iterator method returns a "wrapper object" over this
1.310 + * map's <tt>entrySet()</tt> iterator. The <tt>size</tt> method
1.311 + * delegates to this map's <tt>size</tt> method and the
1.312 + * <tt>contains</tt> method delegates to this map's
1.313 + * <tt>containsKey</tt> method.
1.314 + *
1.315 + * <p>The set is created the first time this method is called,
1.316 + * and returned in response to all subsequent calls. No synchronization
1.317 + * is performed, so there is a slight chance that multiple calls to this
1.318 + * method will not all return the same set.
1.319 + */
1.320 + public Set<K> keySet() {
1.321 + if (keySet == null) {
1.322 + keySet = new AbstractSet<K>() {
1.323 + public Iterator<K> iterator() {
1.324 + return new Iterator<K>() {
1.325 + private Iterator<Entry<K,V>> i = entrySet().iterator();
1.326 +
1.327 + public boolean hasNext() {
1.328 + return i.hasNext();
1.329 + }
1.330 +
1.331 + public K next() {
1.332 + return i.next().getKey();
1.333 + }
1.334 +
1.335 + public void remove() {
1.336 + i.remove();
1.337 + }
1.338 + };
1.339 + }
1.340 +
1.341 + public int size() {
1.342 + return AbstractMap.this.size();
1.343 + }
1.344 +
1.345 + public boolean isEmpty() {
1.346 + return AbstractMap.this.isEmpty();
1.347 + }
1.348 +
1.349 + public void clear() {
1.350 + AbstractMap.this.clear();
1.351 + }
1.352 +
1.353 + public boolean contains(Object k) {
1.354 + return AbstractMap.this.containsKey(k);
1.355 + }
1.356 + };
1.357 + }
1.358 + return keySet;
1.359 + }
1.360 +
1.361 + /**
1.362 + * {@inheritDoc}
1.363 + *
1.364 + * <p>This implementation returns a collection that subclasses {@link
1.365 + * AbstractCollection}. The subclass's iterator method returns a
1.366 + * "wrapper object" over this map's <tt>entrySet()</tt> iterator.
1.367 + * The <tt>size</tt> method delegates to this map's <tt>size</tt>
1.368 + * method and the <tt>contains</tt> method delegates to this map's
1.369 + * <tt>containsValue</tt> method.
1.370 + *
1.371 + * <p>The collection is created the first time this method is called, and
1.372 + * returned in response to all subsequent calls. No synchronization is
1.373 + * performed, so there is a slight chance that multiple calls to this
1.374 + * method will not all return the same collection.
1.375 + */
1.376 + public Collection<V> values() {
1.377 + if (values == null) {
1.378 + values = new AbstractCollection<V>() {
1.379 + public Iterator<V> iterator() {
1.380 + return new Iterator<V>() {
1.381 + private Iterator<Entry<K,V>> i = entrySet().iterator();
1.382 +
1.383 + public boolean hasNext() {
1.384 + return i.hasNext();
1.385 + }
1.386 +
1.387 + public V next() {
1.388 + return i.next().getValue();
1.389 + }
1.390 +
1.391 + public void remove() {
1.392 + i.remove();
1.393 + }
1.394 + };
1.395 + }
1.396 +
1.397 + public int size() {
1.398 + return AbstractMap.this.size();
1.399 + }
1.400 +
1.401 + public boolean isEmpty() {
1.402 + return AbstractMap.this.isEmpty();
1.403 + }
1.404 +
1.405 + public void clear() {
1.406 + AbstractMap.this.clear();
1.407 + }
1.408 +
1.409 + public boolean contains(Object v) {
1.410 + return AbstractMap.this.containsValue(v);
1.411 + }
1.412 + };
1.413 + }
1.414 + return values;
1.415 + }
1.416 +
1.417 + public abstract Set<Entry<K,V>> entrySet();
1.418 +
1.419 +
1.420 + // Comparison and hashing
1.421 +
1.422 + /**
1.423 + * Compares the specified object with this map for equality. Returns
1.424 + * <tt>true</tt> if the given object is also a map and the two maps
1.425 + * represent the same mappings. More formally, two maps <tt>m1</tt> and
1.426 + * <tt>m2</tt> represent the same mappings if
1.427 + * <tt>m1.entrySet().equals(m2.entrySet())</tt>. This ensures that the
1.428 + * <tt>equals</tt> method works properly across different implementations
1.429 + * of the <tt>Map</tt> interface.
1.430 + *
1.431 + * <p>This implementation first checks if the specified object is this map;
1.432 + * if so it returns <tt>true</tt>. Then, it checks if the specified
1.433 + * object is a map whose size is identical to the size of this map; if
1.434 + * not, it returns <tt>false</tt>. If so, it iterates over this map's
1.435 + * <tt>entrySet</tt> collection, and checks that the specified map
1.436 + * contains each mapping that this map contains. If the specified map
1.437 + * fails to contain such a mapping, <tt>false</tt> is returned. If the
1.438 + * iteration completes, <tt>true</tt> is returned.
1.439 + *
1.440 + * @param o object to be compared for equality with this map
1.441 + * @return <tt>true</tt> if the specified object is equal to this map
1.442 + */
1.443 + public boolean equals(Object o) {
1.444 + if (o == this)
1.445 + return true;
1.446 +
1.447 + if (!(o instanceof Map))
1.448 + return false;
1.449 + Map<K,V> m = (Map<K,V>) o;
1.450 + if (m.size() != size())
1.451 + return false;
1.452 +
1.453 + try {
1.454 + Iterator<Entry<K,V>> i = entrySet().iterator();
1.455 + while (i.hasNext()) {
1.456 + Entry<K,V> e = i.next();
1.457 + K key = e.getKey();
1.458 + V value = e.getValue();
1.459 + if (value == null) {
1.460 + if (!(m.get(key)==null && m.containsKey(key)))
1.461 + return false;
1.462 + } else {
1.463 + if (!value.equals(m.get(key)))
1.464 + return false;
1.465 + }
1.466 + }
1.467 + } catch (ClassCastException unused) {
1.468 + return false;
1.469 + } catch (NullPointerException unused) {
1.470 + return false;
1.471 + }
1.472 +
1.473 + return true;
1.474 + }
1.475 +
1.476 + /**
1.477 + * Returns the hash code value for this map. The hash code of a map is
1.478 + * defined to be the sum of the hash codes of each entry in the map's
1.479 + * <tt>entrySet()</tt> view. This ensures that <tt>m1.equals(m2)</tt>
1.480 + * implies that <tt>m1.hashCode()==m2.hashCode()</tt> for any two maps
1.481 + * <tt>m1</tt> and <tt>m2</tt>, as required by the general contract of
1.482 + * {@link Object#hashCode}.
1.483 + *
1.484 + * <p>This implementation iterates over <tt>entrySet()</tt>, calling
1.485 + * {@link Map.Entry#hashCode hashCode()} on each element (entry) in the
1.486 + * set, and adding up the results.
1.487 + *
1.488 + * @return the hash code value for this map
1.489 + * @see Map.Entry#hashCode()
1.490 + * @see Object#equals(Object)
1.491 + * @see Set#equals(Object)
1.492 + */
1.493 + public int hashCode() {
1.494 + int h = 0;
1.495 + Iterator<Entry<K,V>> i = entrySet().iterator();
1.496 + while (i.hasNext())
1.497 + h += i.next().hashCode();
1.498 + return h;
1.499 + }
1.500 +
1.501 + /**
1.502 + * Returns a string representation of this map. The string representation
1.503 + * consists of a list of key-value mappings in the order returned by the
1.504 + * map's <tt>entrySet</tt> view's iterator, enclosed in braces
1.505 + * (<tt>"{}"</tt>). Adjacent mappings are separated by the characters
1.506 + * <tt>", "</tt> (comma and space). Each key-value mapping is rendered as
1.507 + * the key followed by an equals sign (<tt>"="</tt>) followed by the
1.508 + * associated value. Keys and values are converted to strings as by
1.509 + * {@link String#valueOf(Object)}.
1.510 + *
1.511 + * @return a string representation of this map
1.512 + */
1.513 + public String toString() {
1.514 + Iterator<Entry<K,V>> i = entrySet().iterator();
1.515 + if (! i.hasNext())
1.516 + return "{}";
1.517 +
1.518 + StringBuilder sb = new StringBuilder();
1.519 + sb.append('{');
1.520 + for (;;) {
1.521 + Entry<K,V> e = i.next();
1.522 + K key = e.getKey();
1.523 + V value = e.getValue();
1.524 + sb.append(key == this ? "(this Map)" : key);
1.525 + sb.append('=');
1.526 + sb.append(value == this ? "(this Map)" : value);
1.527 + if (! i.hasNext())
1.528 + return sb.append('}').toString();
1.529 + sb.append(',').append(' ');
1.530 + }
1.531 + }
1.532 +
1.533 + /**
1.534 + * Returns a shallow copy of this <tt>AbstractMap</tt> instance: the keys
1.535 + * and values themselves are not cloned.
1.536 + *
1.537 + * @return a shallow copy of this map
1.538 + */
1.539 + protected Object clone() throws CloneNotSupportedException {
1.540 + AbstractMap<K,V> result = (AbstractMap<K,V>)super.clone();
1.541 + result.keySet = null;
1.542 + result.values = null;
1.543 + return result;
1.544 + }
1.545 +
1.546 + /**
1.547 + * Utility method for SimpleEntry and SimpleImmutableEntry.
1.548 + * Test for equality, checking for nulls.
1.549 + */
1.550 + private static boolean eq(Object o1, Object o2) {
1.551 + return o1 == null ? o2 == null : o1.equals(o2);
1.552 + }
1.553 +
1.554 + // Implementation Note: SimpleEntry and SimpleImmutableEntry
1.555 + // are distinct unrelated classes, even though they share
1.556 + // some code. Since you can't add or subtract final-ness
1.557 + // of a field in a subclass, they can't share representations,
1.558 + // and the amount of duplicated code is too small to warrant
1.559 + // exposing a common abstract class.
1.560 +
1.561 +
1.562 + /**
1.563 + * An Entry maintaining a key and a value. The value may be
1.564 + * changed using the <tt>setValue</tt> method. This class
1.565 + * facilitates the process of building custom map
1.566 + * implementations. For example, it may be convenient to return
1.567 + * arrays of <tt>SimpleEntry</tt> instances in method
1.568 + * <tt>Map.entrySet().toArray</tt>.
1.569 + *
1.570 + * @since 1.6
1.571 + */
1.572 + public static class SimpleEntry<K,V>
1.573 + implements Entry<K,V>, java.io.Serializable
1.574 + {
1.575 + private static final long serialVersionUID = -8499721149061103585L;
1.576 +
1.577 + private final K key;
1.578 + private V value;
1.579 +
1.580 + /**
1.581 + * Creates an entry representing a mapping from the specified
1.582 + * key to the specified value.
1.583 + *
1.584 + * @param key the key represented by this entry
1.585 + * @param value the value represented by this entry
1.586 + */
1.587 + public SimpleEntry(K key, V value) {
1.588 + this.key = key;
1.589 + this.value = value;
1.590 + }
1.591 +
1.592 + /**
1.593 + * Creates an entry representing the same mapping as the
1.594 + * specified entry.
1.595 + *
1.596 + * @param entry the entry to copy
1.597 + */
1.598 + public SimpleEntry(Entry<? extends K, ? extends V> entry) {
1.599 + this.key = entry.getKey();
1.600 + this.value = entry.getValue();
1.601 + }
1.602 +
1.603 + /**
1.604 + * Returns the key corresponding to this entry.
1.605 + *
1.606 + * @return the key corresponding to this entry
1.607 + */
1.608 + public K getKey() {
1.609 + return key;
1.610 + }
1.611 +
1.612 + /**
1.613 + * Returns the value corresponding to this entry.
1.614 + *
1.615 + * @return the value corresponding to this entry
1.616 + */
1.617 + public V getValue() {
1.618 + return value;
1.619 + }
1.620 +
1.621 + /**
1.622 + * Replaces the value corresponding to this entry with the specified
1.623 + * value.
1.624 + *
1.625 + * @param value new value to be stored in this entry
1.626 + * @return the old value corresponding to the entry
1.627 + */
1.628 + public V setValue(V value) {
1.629 + V oldValue = this.value;
1.630 + this.value = value;
1.631 + return oldValue;
1.632 + }
1.633 +
1.634 + /**
1.635 + * Compares the specified object with this entry for equality.
1.636 + * Returns {@code true} if the given object is also a map entry and
1.637 + * the two entries represent the same mapping. More formally, two
1.638 + * entries {@code e1} and {@code e2} represent the same mapping
1.639 + * if<pre>
1.640 + * (e1.getKey()==null ?
1.641 + * e2.getKey()==null :
1.642 + * e1.getKey().equals(e2.getKey()))
1.643 + * &&
1.644 + * (e1.getValue()==null ?
1.645 + * e2.getValue()==null :
1.646 + * e1.getValue().equals(e2.getValue()))</pre>
1.647 + * This ensures that the {@code equals} method works properly across
1.648 + * different implementations of the {@code Map.Entry} interface.
1.649 + *
1.650 + * @param o object to be compared for equality with this map entry
1.651 + * @return {@code true} if the specified object is equal to this map
1.652 + * entry
1.653 + * @see #hashCode
1.654 + */
1.655 + public boolean equals(Object o) {
1.656 + if (!(o instanceof Map.Entry))
1.657 + return false;
1.658 + Map.Entry e = (Map.Entry)o;
1.659 + return eq(key, e.getKey()) && eq(value, e.getValue());
1.660 + }
1.661 +
1.662 + /**
1.663 + * Returns the hash code value for this map entry. The hash code
1.664 + * of a map entry {@code e} is defined to be: <pre>
1.665 + * (e.getKey()==null ? 0 : e.getKey().hashCode()) ^
1.666 + * (e.getValue()==null ? 0 : e.getValue().hashCode())</pre>
1.667 + * This ensures that {@code e1.equals(e2)} implies that
1.668 + * {@code e1.hashCode()==e2.hashCode()} for any two Entries
1.669 + * {@code e1} and {@code e2}, as required by the general
1.670 + * contract of {@link Object#hashCode}.
1.671 + *
1.672 + * @return the hash code value for this map entry
1.673 + * @see #equals
1.674 + */
1.675 + public int hashCode() {
1.676 + return (key == null ? 0 : key.hashCode()) ^
1.677 + (value == null ? 0 : value.hashCode());
1.678 + }
1.679 +
1.680 + /**
1.681 + * Returns a String representation of this map entry. This
1.682 + * implementation returns the string representation of this
1.683 + * entry's key followed by the equals character ("<tt>=</tt>")
1.684 + * followed by the string representation of this entry's value.
1.685 + *
1.686 + * @return a String representation of this map entry
1.687 + */
1.688 + public String toString() {
1.689 + return key + "=" + value;
1.690 + }
1.691 +
1.692 + }
1.693 +
1.694 + /**
1.695 + * An Entry maintaining an immutable key and value. This class
1.696 + * does not support method <tt>setValue</tt>. This class may be
1.697 + * convenient in methods that return thread-safe snapshots of
1.698 + * key-value mappings.
1.699 + *
1.700 + * @since 1.6
1.701 + */
1.702 + public static class SimpleImmutableEntry<K,V>
1.703 + implements Entry<K,V>, java.io.Serializable
1.704 + {
1.705 + private static final long serialVersionUID = 7138329143949025153L;
1.706 +
1.707 + private final K key;
1.708 + private final V value;
1.709 +
1.710 + /**
1.711 + * Creates an entry representing a mapping from the specified
1.712 + * key to the specified value.
1.713 + *
1.714 + * @param key the key represented by this entry
1.715 + * @param value the value represented by this entry
1.716 + */
1.717 + public SimpleImmutableEntry(K key, V value) {
1.718 + this.key = key;
1.719 + this.value = value;
1.720 + }
1.721 +
1.722 + /**
1.723 + * Creates an entry representing the same mapping as the
1.724 + * specified entry.
1.725 + *
1.726 + * @param entry the entry to copy
1.727 + */
1.728 + public SimpleImmutableEntry(Entry<? extends K, ? extends V> entry) {
1.729 + this.key = entry.getKey();
1.730 + this.value = entry.getValue();
1.731 + }
1.732 +
1.733 + /**
1.734 + * Returns the key corresponding to this entry.
1.735 + *
1.736 + * @return the key corresponding to this entry
1.737 + */
1.738 + public K getKey() {
1.739 + return key;
1.740 + }
1.741 +
1.742 + /**
1.743 + * Returns the value corresponding to this entry.
1.744 + *
1.745 + * @return the value corresponding to this entry
1.746 + */
1.747 + public V getValue() {
1.748 + return value;
1.749 + }
1.750 +
1.751 + /**
1.752 + * Replaces the value corresponding to this entry with the specified
1.753 + * value (optional operation). This implementation simply throws
1.754 + * <tt>UnsupportedOperationException</tt>, as this class implements
1.755 + * an <i>immutable</i> map entry.
1.756 + *
1.757 + * @param value new value to be stored in this entry
1.758 + * @return (Does not return)
1.759 + * @throws UnsupportedOperationException always
1.760 + */
1.761 + public V setValue(V value) {
1.762 + throw new UnsupportedOperationException();
1.763 + }
1.764 +
1.765 + /**
1.766 + * Compares the specified object with this entry for equality.
1.767 + * Returns {@code true} if the given object is also a map entry and
1.768 + * the two entries represent the same mapping. More formally, two
1.769 + * entries {@code e1} and {@code e2} represent the same mapping
1.770 + * if<pre>
1.771 + * (e1.getKey()==null ?
1.772 + * e2.getKey()==null :
1.773 + * e1.getKey().equals(e2.getKey()))
1.774 + * &&
1.775 + * (e1.getValue()==null ?
1.776 + * e2.getValue()==null :
1.777 + * e1.getValue().equals(e2.getValue()))</pre>
1.778 + * This ensures that the {@code equals} method works properly across
1.779 + * different implementations of the {@code Map.Entry} interface.
1.780 + *
1.781 + * @param o object to be compared for equality with this map entry
1.782 + * @return {@code true} if the specified object is equal to this map
1.783 + * entry
1.784 + * @see #hashCode
1.785 + */
1.786 + public boolean equals(Object o) {
1.787 + if (!(o instanceof Map.Entry))
1.788 + return false;
1.789 + Map.Entry e = (Map.Entry)o;
1.790 + return eq(key, e.getKey()) && eq(value, e.getValue());
1.791 + }
1.792 +
1.793 + /**
1.794 + * Returns the hash code value for this map entry. The hash code
1.795 + * of a map entry {@code e} is defined to be: <pre>
1.796 + * (e.getKey()==null ? 0 : e.getKey().hashCode()) ^
1.797 + * (e.getValue()==null ? 0 : e.getValue().hashCode())</pre>
1.798 + * This ensures that {@code e1.equals(e2)} implies that
1.799 + * {@code e1.hashCode()==e2.hashCode()} for any two Entries
1.800 + * {@code e1} and {@code e2}, as required by the general
1.801 + * contract of {@link Object#hashCode}.
1.802 + *
1.803 + * @return the hash code value for this map entry
1.804 + * @see #equals
1.805 + */
1.806 + public int hashCode() {
1.807 + return (key == null ? 0 : key.hashCode()) ^
1.808 + (value == null ? 0 : value.hashCode());
1.809 + }
1.810 +
1.811 + /**
1.812 + * Returns a String representation of this map entry. This
1.813 + * implementation returns the string representation of this
1.814 + * entry's key followed by the equals character ("<tt>=</tt>")
1.815 + * followed by the string representation of this entry's value.
1.816 + *
1.817 + * @return a String representation of this map entry
1.818 + */
1.819 + public String toString() {
1.820 + return key + "=" + value;
1.821 + }
1.822 +
1.823 + }
1.824 +
1.825 +}