com.google.gwt.emul.java.util.AbstractMap Maven / Gradle / Ivy
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/*
* Copyright 2007 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package java.util;
import static com.google.gwt.core.shared.impl.InternalPreconditions.checkNotNull;
/**
* Skeletal implementation of the Map interface. [Sun
* docs]
*
* @param the key type.
* @param the value type.
*/
public abstract class AbstractMap implements Map {
/**
* A mutable {@link Map.Entry} shared by several {@link Map} implementations.
*/
public static class SimpleEntry extends AbstractEntry {
public SimpleEntry(K key, V value) {
super(key, value);
}
public SimpleEntry(Entry entry) {
super(entry.getKey(), entry.getValue());
}
}
/**
* An immutable {@link Map.Entry} shared by several {@link Map} implementations.
*/
public static class SimpleImmutableEntry extends AbstractEntry {
public SimpleImmutableEntry(K key, V value) {
super(key, value);
}
public SimpleImmutableEntry(Entry entry) {
super(entry.getKey(), entry.getValue());
}
@Override
public V setValue(V value) {
throw new UnsupportedOperationException();
}
}
/**
* Basic {@link Map.Entry} implementation used by {@link SimpleEntry}
* and {@link SimpleImmutableEntry}.
*/
private abstract static class AbstractEntry implements Entry {
private final K key;
private V value;
protected AbstractEntry(K key, V value) {
this.key = key;
this.value = value;
}
@Override
public K getKey() {
return key;
}
@Override
public V getValue() {
return value;
}
@Override
public V setValue(V value) {
V oldValue = this.value;
this.value = value;
return oldValue;
}
@Override
public boolean equals(Object other) {
if (!(other instanceof Entry)) {
return false;
}
Entry entry = (Entry) other;
return Objects.equals(key, entry.getKey())
&& Objects.equals(value, entry.getValue());
}
/**
* Calculate the hash code using Sun's specified algorithm.
*/
@Override
public int hashCode() {
return Objects.hashCode(key) ^ Objects.hashCode(value);
}
@Override
public String toString() {
// for compatibility with the real Jre: issue 3422
return key + "=" + value;
}
}
protected AbstractMap() {
}
@Override
public void clear() {
entrySet().clear();
}
@Override
public boolean containsKey(Object key) {
return implFindEntry(key, false) != null;
}
@Override
public boolean containsValue(Object value) {
for (Entry entry : entrySet()) {
V v = entry.getValue();
if (Objects.equals(value, v)) {
return true;
}
}
return false;
}
boolean containsEntry(Entry entry) {
Object key = entry.getKey();
Object value = entry.getValue();
Object ourValue = get(key);
if (!Objects.equals(value, ourValue)) {
return false;
}
// Perhaps it was null and we don't contain the key?
if (ourValue == null && !containsKey(key)) {
return false;
}
return true;
}
@Override
public abstract Set> entrySet();
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof Map)) {
return false;
}
Map otherMap = (Map) obj;
if (size() != otherMap.size()) {
return false;
}
for (Entry entry : otherMap.entrySet()) {
if (!containsEntry(entry)) {
return false;
}
}
return true;
}
@Override
public V get(Object key) {
return getEntryValueOrNull(implFindEntry(key, false));
}
@Override
public int hashCode() {
return Collections.hashCode(entrySet());
}
@Override
public boolean isEmpty() {
return size() == 0;
}
@Override
public Set keySet() {
return new AbstractSet() {
@Override
public void clear() {
AbstractMap.this.clear();
}
@Override
public boolean contains(Object key) {
return containsKey(key);
}
@Override
public Iterator iterator() {
final Iterator> outerIter = entrySet().iterator();
return new Iterator() {
@Override
public boolean hasNext() {
return outerIter.hasNext();
}
@Override
public K next() {
Entry entry = outerIter.next();
return entry.getKey();
}
@Override
public void remove() {
outerIter.remove();
}
};
}
@Override
public boolean remove(Object key) {
if (containsKey(key)) {
AbstractMap.this.remove(key);
return true;
}
return false;
}
@Override
public int size() {
return AbstractMap.this.size();
}
};
}
public V put(K key, V value) {
throw new UnsupportedOperationException("Put not supported on this map");
}
@Override
public void putAll(Map map) {
checkNotNull(map);
for (Entry e : map.entrySet()) {
put(e.getKey(), e.getValue());
}
}
@Override
public V remove(Object key) {
return getEntryValueOrNull(implFindEntry(key, true));
}
public int size() {
return entrySet().size();
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder("{");
boolean comma = false;
for (Entry entry : entrySet()) {
if (comma) {
sb.append(", ");
} else {
comma = true;
}
sb.append(toString(entry.getKey()));
sb.append("=");
sb.append(toString(entry.getValue()));
}
sb.append("}");
return sb.toString();
}
private String toString(Object o) {
return o == this ? "(this Map)" : String.valueOf(o);
}
@Override
public Collection values() {
return new AbstractCollection() {
@Override
public void clear() {
AbstractMap.this.clear();
}
@Override
public boolean contains(Object value) {
return containsValue(value);
}
@Override
public Iterator iterator() {
final Iterator> outerIter = entrySet().iterator();
return new Iterator() {
@Override
public boolean hasNext() {
return outerIter.hasNext();
}
@Override
public V next() {
Entry entry = outerIter.next();
return entry.getValue();
}
@Override
public void remove() {
outerIter.remove();
}
};
}
@Override
public int size() {
return AbstractMap.this.size();
}
};
}
static K getEntryKeyOrNull(Entry entry) {
return entry == null ? null : entry.getKey();
}
static V getEntryValueOrNull(Entry entry) {
return entry == null ? null : entry.getValue();
}
private Entry implFindEntry(Object key, boolean remove) {
for (Iterator> iter = entrySet().iterator(); iter.hasNext();) {
Entry entry = iter.next();
K k = entry.getKey();
if (Objects.equals(key, k)) {
if (remove) {
entry = new SimpleEntry(entry.getKey(), entry.getValue());
iter.remove();
}
return entry;
}
}
return null;
}
}