320 lines
9.2 KiB
Java
320 lines
9.2 KiB
Java
|
/*
|
||
|
|
* Copyright (C) 2007 The Guava Authors
|
||
|
|
*
|
||
|
|
* 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 com.google.common.collect;
|
||
|
|
|
||
|
|
import java.util.Collection;
|
||
|
|
import java.util.Iterator;
|
||
|
|
import java.util.Map;
|
||
|
|
import java.util.Set;
|
||
|
|
|
||
|
|
import javax.annotation.Nullable;
|
||
|
|
|
||
|
|
import com.google.common.annotations.Beta;
|
||
|
|
import com.google.common.annotations.GwtCompatible;
|
||
|
|
import com.google.common.base.Objects;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A map which forwards all its method calls to another map. Subclasses should
|
||
|
|
* override one or more methods to modify the behavior of the backing map as
|
||
|
|
* desired per the
|
||
|
|
* <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator
|
||
|
|
* pattern</a>.
|
||
|
|
*
|
||
|
|
* <p>
|
||
|
|
* <i>Warning:</i> The methods of {@code ForwardingMap} forward
|
||
|
|
* <i>indiscriminately</i> to the methods of the delegate. For example,
|
||
|
|
* overriding {@link #put} alone <i>will not</i> change the behavior of
|
||
|
|
* {@link #putAll}, which can lead to unexpected behavior. In this case, you
|
||
|
|
* should override {@code putAll} as well, either providing your own
|
||
|
|
* implementation, or delegating to the provided {@code standardPutAll} method.
|
||
|
|
*
|
||
|
|
* <p>
|
||
|
|
* Each of the {@code standard} methods, where appropriate, use
|
||
|
|
* {@link Objects#equal} to test equality for both keys and values. This may not
|
||
|
|
* be the desired behavior for map implementations that use non-standard notions
|
||
|
|
* of key equality, such as a {@code SortedMap} whose comparator is not
|
||
|
|
* consistent with {@code equals}.
|
||
|
|
*
|
||
|
|
* <p>
|
||
|
|
* The {@code standard} methods and the collection views they return are not
|
||
|
|
* guaranteed to be thread-safe, even when all of the methods that they depend
|
||
|
|
* on are thread-safe.
|
||
|
|
*
|
||
|
|
* @author Kevin Bourrillion
|
||
|
|
* @author Jared Levy
|
||
|
|
* @author Louis Wasserman
|
||
|
|
* @since 2.0 (imported from Google Collections Library)
|
||
|
|
*/
|
||
|
|
@GwtCompatible
|
||
|
|
public abstract class ForwardingMap<K, V> extends ForwardingObject implements Map<K, V> {
|
||
|
|
// TODO(user): identify places where thread safety is actually lost
|
||
|
|
|
||
|
|
/** Constructor for use by subclasses. */
|
||
|
|
protected ForwardingMap() {
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
protected abstract Map<K, V> delegate();
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public int size() {
|
||
|
|
return delegate().size();
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public boolean isEmpty() {
|
||
|
|
return delegate().isEmpty();
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public V remove(Object object) {
|
||
|
|
return delegate().remove(object);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public void clear() {
|
||
|
|
delegate().clear();
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public boolean containsKey(@Nullable Object key) {
|
||
|
|
return delegate().containsKey(key);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public boolean containsValue(@Nullable Object value) {
|
||
|
|
return delegate().containsValue(value);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public V get(@Nullable Object key) {
|
||
|
|
return delegate().get(key);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public V put(K key, V value) {
|
||
|
|
return delegate().put(key, value);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public void putAll(Map<? extends K, ? extends V> map) {
|
||
|
|
delegate().putAll(map);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public Set<K> keySet() {
|
||
|
|
return delegate().keySet();
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public Collection<V> values() {
|
||
|
|
return delegate().values();
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public Set<Entry<K, V>> entrySet() {
|
||
|
|
return delegate().entrySet();
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public boolean equals(@Nullable Object object) {
|
||
|
|
return object == this || delegate().equals(object);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public int hashCode() {
|
||
|
|
return delegate().hashCode();
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible definition of {@link #putAll(Map)} in terms of
|
||
|
|
* {@link #put(Object, Object)}. If you override {@link #put(Object, Object)},
|
||
|
|
* you may wish to override {@link #putAll(Map)} to forward to this
|
||
|
|
* implementation.
|
||
|
|
*
|
||
|
|
* @since 7.0
|
||
|
|
*/
|
||
|
|
protected void standardPutAll(Map<? extends K, ? extends V> map) {
|
||
|
|
Maps.putAllImpl(this, map);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible, albeit inefficient, definition of {@link #remove} in terms of the
|
||
|
|
* {@code iterator} method of {@link #entrySet}. If you override
|
||
|
|
* {@link #entrySet}, you may wish to override {@link #remove} to forward to
|
||
|
|
* this implementation.
|
||
|
|
*
|
||
|
|
* <p>
|
||
|
|
* Alternately, you may wish to override {@link #remove} with {@code
|
||
|
|
* keySet().remove}, assuming that approach would not lead to an infinite loop.
|
||
|
|
*
|
||
|
|
* @since 7.0
|
||
|
|
*/
|
||
|
|
@Beta
|
||
|
|
protected V standardRemove(@Nullable Object key) {
|
||
|
|
Iterator<Entry<K, V>> entryIterator = entrySet().iterator();
|
||
|
|
while (entryIterator.hasNext()) {
|
||
|
|
Entry<K, V> entry = entryIterator.next();
|
||
|
|
if (Objects.equal(entry.getKey(), key)) {
|
||
|
|
V value = entry.getValue();
|
||
|
|
entryIterator.remove();
|
||
|
|
return value;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return null;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible definition of {@link #clear} in terms of the {@code iterator}
|
||
|
|
* method of {@link #entrySet}. In many cases, you may wish to override
|
||
|
|
* {@link #clear} to forward to this implementation.
|
||
|
|
*
|
||
|
|
* @since 7.0
|
||
|
|
*/
|
||
|
|
protected void standardClear() {
|
||
|
|
Iterators.clear(entrySet().iterator());
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible implementation of {@link Map#keySet} in terms of the following
|
||
|
|
* methods: {@link ForwardingMap#clear}, {@link ForwardingMap#containsKey},
|
||
|
|
* {@link ForwardingMap#isEmpty}, {@link ForwardingMap#remove},
|
||
|
|
* {@link ForwardingMap#size}, and the {@link Set#iterator} method of
|
||
|
|
* {@link ForwardingMap#entrySet}. In many cases, you may wish to override
|
||
|
|
* {@link ForwardingMap#keySet} to forward to this implementation or a subclass
|
||
|
|
* thereof.
|
||
|
|
*
|
||
|
|
* @since 10.0
|
||
|
|
*/
|
||
|
|
@Beta
|
||
|
|
protected class StandardKeySet extends Maps.KeySet<K, V> {
|
||
|
|
/** Constructor for use by subclasses. */
|
||
|
|
public StandardKeySet() {
|
||
|
|
super(ForwardingMap.this);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible, albeit inefficient, definition of {@link #containsKey} in terms
|
||
|
|
* of the {@code iterator} method of {@link #entrySet}. If you override
|
||
|
|
* {@link #entrySet}, you may wish to override {@link #containsKey} to forward
|
||
|
|
* to this implementation.
|
||
|
|
*
|
||
|
|
* @since 7.0
|
||
|
|
*/
|
||
|
|
@Beta
|
||
|
|
protected boolean standardContainsKey(@Nullable Object key) {
|
||
|
|
return Maps.containsKeyImpl(this, key);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible implementation of {@link Map#values} in terms of the following
|
||
|
|
* methods: {@link ForwardingMap#clear}, {@link ForwardingMap#containsValue},
|
||
|
|
* {@link ForwardingMap#isEmpty}, {@link ForwardingMap#size}, and the
|
||
|
|
* {@link Set#iterator} method of {@link ForwardingMap#entrySet}. In many cases,
|
||
|
|
* you may wish to override {@link ForwardingMap#values} to forward to this
|
||
|
|
* implementation or a subclass thereof.
|
||
|
|
*
|
||
|
|
* @since 10.0
|
||
|
|
*/
|
||
|
|
@Beta
|
||
|
|
protected class StandardValues extends Maps.Values<K, V> {
|
||
|
|
/** Constructor for use by subclasses. */
|
||
|
|
public StandardValues() {
|
||
|
|
super(ForwardingMap.this);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible definition of {@link #containsValue} in terms of the {@code
|
||
|
|
* iterator} method of {@link #entrySet}. If you override {@link #entrySet}, you
|
||
|
|
* may wish to override {@link #containsValue} to forward to this
|
||
|
|
* implementation.
|
||
|
|
*
|
||
|
|
* @since 7.0
|
||
|
|
*/
|
||
|
|
protected boolean standardContainsValue(@Nullable Object value) {
|
||
|
|
return Maps.containsValueImpl(this, value);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible implementation of {@link Map#entrySet} in terms of the following
|
||
|
|
* methods: {@link ForwardingMap#clear}, {@link ForwardingMap#containsKey},
|
||
|
|
* {@link ForwardingMap#get}, {@link ForwardingMap#isEmpty},
|
||
|
|
* {@link ForwardingMap#remove}, and {@link ForwardingMap#size}. In many cases,
|
||
|
|
* you may wish to override {@link #entrySet} to forward to this implementation
|
||
|
|
* or a subclass thereof.
|
||
|
|
*
|
||
|
|
* @since 10.0
|
||
|
|
*/
|
||
|
|
@Beta
|
||
|
|
protected abstract class StandardEntrySet extends Maps.EntrySet<K, V> {
|
||
|
|
/** Constructor for use by subclasses. */
|
||
|
|
public StandardEntrySet() {
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
Map<K, V> map() {
|
||
|
|
return ForwardingMap.this;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible definition of {@link #isEmpty} in terms of the {@code iterator}
|
||
|
|
* method of {@link #entrySet}. If you override {@link #entrySet}, you may wish
|
||
|
|
* to override {@link #isEmpty} to forward to this implementation.
|
||
|
|
*
|
||
|
|
* @since 7.0
|
||
|
|
*/
|
||
|
|
protected boolean standardIsEmpty() {
|
||
|
|
return !entrySet().iterator().hasNext();
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible definition of {@link #equals} in terms of the {@code equals}
|
||
|
|
* method of {@link #entrySet}. If you override {@link #entrySet}, you may wish
|
||
|
|
* to override {@link #equals} to forward to this implementation.
|
||
|
|
*
|
||
|
|
* @since 7.0
|
||
|
|
*/
|
||
|
|
protected boolean standardEquals(@Nullable Object object) {
|
||
|
|
return Maps.equalsImpl(this, object);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible definition of {@link #hashCode} in terms of the {@code iterator}
|
||
|
|
* method of {@link #entrySet}. If you override {@link #entrySet}, you may wish
|
||
|
|
* to override {@link #hashCode} to forward to this implementation.
|
||
|
|
*
|
||
|
|
* @since 7.0
|
||
|
|
*/
|
||
|
|
protected int standardHashCode() {
|
||
|
|
return Sets.hashCodeImpl(entrySet());
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A sensible definition of {@link #toString} in terms of the {@code iterator}
|
||
|
|
* method of {@link #entrySet}. If you override {@link #entrySet}, you may wish
|
||
|
|
* to override {@link #toString} to forward to this implementation.
|
||
|
|
*
|
||
|
|
* @since 7.0
|
||
|
|
*/
|
||
|
|
protected String standardToString() {
|
||
|
|
return Maps.toStringImpl(this);
|
||
|
|
}
|
||
|
|
}
|