| /* |
| * 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 com.google.common.annotations.Beta; |
| import com.google.common.annotations.GwtCompatible; |
| import com.google.common.base.Objects; |
| import com.google.errorprone.annotations.CanIgnoreReturnValue; |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.Set; |
| import org.checkerframework.checker.nullness.compatqual.NullableDecl; |
| |
| /** |
| * A multiset which forwards all its method calls to another multiset. Subclasses should override |
| * one or more methods to modify the behavior of the backing multiset as desired per the <a |
| * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>. |
| * |
| * <p><b>Warning:</b> The methods of {@code ForwardingMultiset} forward <b>indiscriminately</b> to |
| * the methods of the delegate. For example, overriding {@link #add(Object, int)} alone <b>will |
| * not</b> change the behavior of {@link #add(Object)}, which can lead to unexpected behavior. In |
| * this case, you should override {@code add(Object)} as well, either providing your own |
| * implementation, or delegating to the provided {@code standardAdd} method. |
| * |
| * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code |
| * default} methods. Instead, it inherits their default implementations. When those implementations |
| * invoke methods, they invoke methods on the {@code ForwardingMultiset}. |
| * |
| * <p>The {@code standard} methods and any 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 Louis Wasserman |
| * @since 2.0 |
| */ |
| @GwtCompatible |
| public abstract class ForwardingMultiset<E> extends ForwardingCollection<E> implements Multiset<E> { |
| |
| /** Constructor for use by subclasses. */ |
| protected ForwardingMultiset() {} |
| |
| @Override |
| protected abstract Multiset<E> delegate(); |
| |
| @Override |
| public int count(Object element) { |
| return delegate().count(element); |
| } |
| |
| @CanIgnoreReturnValue |
| @Override |
| public int add(E element, int occurrences) { |
| return delegate().add(element, occurrences); |
| } |
| |
| @CanIgnoreReturnValue |
| @Override |
| public int remove(Object element, int occurrences) { |
| return delegate().remove(element, occurrences); |
| } |
| |
| @Override |
| public Set<E> elementSet() { |
| return delegate().elementSet(); |
| } |
| |
| @Override |
| public Set<Entry<E>> entrySet() { |
| return delegate().entrySet(); |
| } |
| |
| @Override |
| public boolean equals(@NullableDecl Object object) { |
| return object == this || delegate().equals(object); |
| } |
| |
| @Override |
| public int hashCode() { |
| return delegate().hashCode(); |
| } |
| |
| @CanIgnoreReturnValue |
| @Override |
| public int setCount(E element, int count) { |
| return delegate().setCount(element, count); |
| } |
| |
| @CanIgnoreReturnValue |
| @Override |
| public boolean setCount(E element, int oldCount, int newCount) { |
| return delegate().setCount(element, oldCount, newCount); |
| } |
| |
| /** |
| * A sensible definition of {@link #contains} in terms of {@link #count}. If you override {@link |
| * #count}, you may wish to override {@link #contains} to forward to this implementation. |
| * |
| * @since 7.0 |
| */ |
| @Override |
| protected boolean standardContains(@NullableDecl Object object) { |
| return count(object) > 0; |
| } |
| |
| /** |
| * A sensible definition of {@link #clear} in terms of the {@code iterator} method of {@link |
| * #entrySet}. If you override {@link #entrySet}, you may wish to override {@link #clear} to |
| * forward to this implementation. |
| * |
| * @since 7.0 |
| */ |
| @Override |
| protected void standardClear() { |
| Iterators.clear(entrySet().iterator()); |
| } |
| |
| /** |
| * A sensible, albeit inefficient, definition of {@link #count} in terms of {@link #entrySet}. If |
| * you override {@link #entrySet}, you may wish to override {@link #count} to forward to this |
| * implementation. |
| * |
| * @since 7.0 |
| */ |
| @Beta |
| protected int standardCount(@NullableDecl Object object) { |
| for (Entry<?> entry : this.entrySet()) { |
| if (Objects.equal(entry.getElement(), object)) { |
| return entry.getCount(); |
| } |
| } |
| return 0; |
| } |
| |
| /** |
| * A sensible definition of {@link #add(Object)} in terms of {@link #add(Object, int)}. If you |
| * override {@link #add(Object, int)}, you may wish to override {@link #add(Object)} to forward to |
| * this implementation. |
| * |
| * @since 7.0 |
| */ |
| protected boolean standardAdd(E element) { |
| add(element, 1); |
| return true; |
| } |
| |
| /** |
| * A sensible definition of {@link #addAll(Collection)} in terms of {@link #add(Object)} and |
| * {@link #add(Object, int)}. If you override either of these methods, you may wish to override |
| * {@link #addAll(Collection)} to forward to this implementation. |
| * |
| * @since 7.0 |
| */ |
| @Beta |
| @Override |
| protected boolean standardAddAll(Collection<? extends E> elementsToAdd) { |
| return Multisets.addAllImpl(this, elementsToAdd); |
| } |
| |
| /** |
| * A sensible definition of {@link #remove(Object)} in terms of {@link #remove(Object, int)}. If |
| * you override {@link #remove(Object, int)}, you may wish to override {@link #remove(Object)} to |
| * forward to this implementation. |
| * |
| * @since 7.0 |
| */ |
| @Override |
| protected boolean standardRemove(Object element) { |
| return remove(element, 1) > 0; |
| } |
| |
| /** |
| * A sensible definition of {@link #removeAll} in terms of the {@code removeAll} method of {@link |
| * #elementSet}. If you override {@link #elementSet}, you may wish to override {@link #removeAll} |
| * to forward to this implementation. |
| * |
| * @since 7.0 |
| */ |
| @Override |
| protected boolean standardRemoveAll(Collection<?> elementsToRemove) { |
| return Multisets.removeAllImpl(this, elementsToRemove); |
| } |
| |
| /** |
| * A sensible definition of {@link #retainAll} in terms of the {@code retainAll} method of {@link |
| * #elementSet}. If you override {@link #elementSet}, you may wish to override {@link #retainAll} |
| * to forward to this implementation. |
| * |
| * @since 7.0 |
| */ |
| @Override |
| protected boolean standardRetainAll(Collection<?> elementsToRetain) { |
| return Multisets.retainAllImpl(this, elementsToRetain); |
| } |
| |
| /** |
| * A sensible definition of {@link #setCount(Object, int)} in terms of {@link #count(Object)}, |
| * {@link #add(Object, int)}, and {@link #remove(Object, int)}. {@link #entrySet()}. If you |
| * override any of these methods, you may wish to override {@link #setCount(Object, int)} to |
| * forward to this implementation. |
| * |
| * @since 7.0 |
| */ |
| protected int standardSetCount(E element, int count) { |
| return Multisets.setCountImpl(this, element, count); |
| } |
| |
| /** |
| * A sensible definition of {@link #setCount(Object, int, int)} in terms of {@link #count(Object)} |
| * and {@link #setCount(Object, int)}. If you override either of these methods, you may wish to |
| * override {@link #setCount(Object, int, int)} to forward to this implementation. |
| * |
| * @since 7.0 |
| */ |
| protected boolean standardSetCount(E element, int oldCount, int newCount) { |
| return Multisets.setCountImpl(this, element, oldCount, newCount); |
| } |
| |
| /** |
| * A sensible implementation of {@link Multiset#elementSet} in terms of the following methods: |
| * {@link ForwardingMultiset#clear}, {@link ForwardingMultiset#contains}, {@link |
| * ForwardingMultiset#containsAll}, {@link ForwardingMultiset#count}, {@link |
| * ForwardingMultiset#isEmpty}, the {@link Set#size} and {@link Set#iterator} methods of {@link |
| * ForwardingMultiset#entrySet}, and {@link ForwardingMultiset#remove(Object, int)}. In many |
| * situations, you may wish to override {@link ForwardingMultiset#elementSet} to forward to this |
| * implementation or a subclass thereof. |
| * |
| * @since 10.0 |
| */ |
| @Beta |
| protected class StandardElementSet extends Multisets.ElementSet<E> { |
| /** Constructor for use by subclasses. */ |
| public StandardElementSet() {} |
| |
| @Override |
| Multiset<E> multiset() { |
| return ForwardingMultiset.this; |
| } |
| |
| @Override |
| public Iterator<E> iterator() { |
| return Multisets.elementIterator(multiset().entrySet().iterator()); |
| } |
| } |
| |
| /** |
| * A sensible definition of {@link #iterator} in terms of {@link #entrySet} and {@link |
| * #remove(Object)}. If you override either of these methods, you may wish to override {@link |
| * #iterator} to forward to this implementation. |
| * |
| * @since 7.0 |
| */ |
| protected Iterator<E> standardIterator() { |
| return Multisets.iteratorImpl(this); |
| } |
| |
| /** |
| * A sensible, albeit inefficient, definition of {@link #size} in terms of {@link #entrySet}. If |
| * you override {@link #entrySet}, you may wish to override {@link #size} to forward to this |
| * implementation. |
| * |
| * @since 7.0 |
| */ |
| protected int standardSize() { |
| return Multisets.linearTimeSizeImpl(this); |
| } |
| |
| /** |
| * A sensible, albeit inefficient, definition of {@link #equals} in terms of {@code |
| * entrySet().size()} and {@link #count}. If you override either of these methods, you may wish to |
| * override {@link #equals} to forward to this implementation. |
| * |
| * @since 7.0 |
| */ |
| protected boolean standardEquals(@NullableDecl Object object) { |
| return Multisets.equalsImpl(this, object); |
| } |
| |
| /** |
| * A sensible definition of {@link #hashCode} as {@code entrySet().hashCode()} . If you override |
| * {@link #entrySet}, you may wish to override {@link #hashCode} to forward to this |
| * implementation. |
| * |
| * @since 7.0 |
| */ |
| protected int standardHashCode() { |
| return entrySet().hashCode(); |
| } |
| |
| /** |
| * A sensible definition of {@link #toString} as {@code entrySet().toString()} . If you override |
| * {@link #entrySet}, you may wish to override {@link #toString} to forward to this |
| * implementation. |
| * |
| * @since 7.0 |
| */ |
| @Override |
| protected String standardToString() { |
| return entrySet().toString(); |
| } |
| } |