| /* |
| * Copyright (C) 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 com.google.inject.internal.util; |
| |
| import com.google.inject.internal.Nullable; |
| |
| import java.util.Collection; |
| import java.util.Map; |
| import java.util.Set; |
| |
| /** |
| * 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>. |
| * |
| * @see ForwardingObject |
| * @author Kevin Bourrillion |
| * @author Jared Levy |
| */ |
| public abstract class ForwardingMap<K, V> extends ForwardingObject |
| implements Map<K, V> { |
| |
| @Override protected abstract Map<K, V> delegate(); |
| |
| public int size() { |
| return delegate().size(); |
| } |
| |
| public boolean isEmpty() { |
| return delegate().isEmpty(); |
| } |
| |
| public V remove(Object object) { |
| return delegate().remove(object); |
| } |
| |
| public void clear() { |
| delegate().clear(); |
| } |
| |
| public boolean containsKey(Object key) { |
| return delegate().containsKey(key); |
| } |
| |
| public boolean containsValue(Object value) { |
| return delegate().containsValue(value); |
| } |
| |
| public V get(Object key) { |
| return delegate().get(key); |
| } |
| |
| public V put(K key, V value) { |
| return delegate().put(key, value); |
| } |
| |
| public void putAll(Map<? extends K, ? extends V> map) { |
| delegate().putAll(map); |
| } |
| |
| private transient Set<K> keySet; |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>The returned set's {@code removeAll} and {@code retainAll} methods |
| * always throw a {@link NullPointerException} when given a null collection. |
| */ |
| public Set<K> keySet() { |
| return (keySet == null) ? keySet = createKeySet() : keySet; |
| } |
| |
| /** |
| * Generates a {@link Set} for use by {@link #keySet()}. |
| * |
| * <p>ForwardingMap's implementation of keySet() calls this method to |
| * generate a collection of values, and then reuses that Set |
| * for subsequent invocations. By default, this Set is essentially the |
| * result of invoking keySet() on the delegate. Override this method if you |
| * want to provide another implementation. |
| * |
| * @return A set for use by keySet(). |
| */ |
| protected Set<K> createKeySet() { |
| final Set<K> delegate = delegate().keySet(); |
| return new ForwardingSet<K>() { |
| @Override protected Set<K> delegate() { |
| return delegate; |
| } |
| }; |
| } |
| |
| private transient Collection<V> values; |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>The returned collection's {@code removeAll} and {@code retainAll} |
| * methods always throw a {@link NullPointerException} when given a null |
| * collection. |
| */ |
| public Collection<V> values() { |
| return (values == null) ? values = createValues() : values; |
| } |
| |
| /** |
| * Generates a {@link Collection} for use by {@link #values()}. |
| * |
| * <p>ForwardingMap's implementation of {@code values()} calls this method to |
| * generate a collection of values, and then reuses that collection |
| * for subsequent invocations. By default, this collection is essentially the |
| * result of invoking values() on the delegate. Override this method if you |
| * want to provide another implementation. |
| * |
| * @return A set for use by values(). |
| */ |
| protected Collection<V> createValues() { |
| final Collection<V> delegate = delegate().values(); |
| return new ForwardingCollection<V>() { |
| @Override protected Collection<V> delegate() { |
| return delegate; |
| } |
| }; |
| } |
| |
| private transient Set<Entry<K, V>> entrySet; |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>The returned set's {@code removeAll} and {@code retainAll} methods |
| * always throw a {@link NullPointerException} when given a null collection. |
| */ |
| public Set<Entry<K, V>> entrySet() { |
| return (entrySet == null) ? entrySet = createEntrySet() : entrySet; |
| } |
| |
| /** |
| * Generates a {@link Set} for use by {@link #entrySet()}. |
| * |
| * <p>ForwardingMap's implementation of entrySet() calls this method to |
| * generate a set of entries, and then reuses that set for subsequent |
| * invocations. By default, this set is essentially the result of invoking |
| * entrySet() on the delegate. Override this method if you want to |
| * provide another implementation. |
| * |
| * @return A set for use by entrySet(). |
| */ |
| protected Set<Entry<K, V>> createEntrySet() { |
| final Set<Entry<K, V>> delegate = delegate().entrySet(); |
| return new ForwardingSet<Entry<K, V>>() { |
| @Override protected Set<Entry<K, V>> delegate() { |
| return delegate; |
| } |
| }; |
| } |
| |
| @Override public boolean equals(@Nullable Object object) { |
| return object == this || delegate().equals(object); |
| } |
| |
| @Override public int hashCode() { |
| return delegate().hashCode(); |
| } |
| } |