| /* |
| * Copyright (C) 2011 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 java.util.Comparator; |
| import java.util.Iterator; |
| import java.util.NavigableSet; |
| |
| /** |
| * A sorted multiset which forwards all its method calls to another sorted 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 ForwardingSortedMultiset} 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 ForwardingSortedMultiset}. |
| * |
| * <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 Louis Wasserman |
| * @since 15.0 |
| */ |
| @Beta |
| @GwtCompatible(emulated = true) |
| public abstract class ForwardingSortedMultiset<E> extends ForwardingMultiset<E> |
| implements SortedMultiset<E> { |
| /** Constructor for use by subclasses. */ |
| protected ForwardingSortedMultiset() {} |
| |
| @Override |
| protected abstract SortedMultiset<E> delegate(); |
| |
| @Override |
| public NavigableSet<E> elementSet() { |
| return delegate().elementSet(); |
| } |
| |
| /** |
| * A sensible implementation of {@link SortedMultiset#elementSet} in terms of the following |
| * methods: {@link SortedMultiset#clear}, {@link SortedMultiset#comparator}, {@link |
| * SortedMultiset#contains}, {@link SortedMultiset#containsAll}, {@link SortedMultiset#count}, |
| * {@link SortedMultiset#firstEntry} {@link SortedMultiset#headMultiset}, {@link |
| * SortedMultiset#isEmpty}, {@link SortedMultiset#lastEntry}, {@link SortedMultiset#subMultiset}, |
| * {@link SortedMultiset#tailMultiset}, the {@code size()} and {@code iterator()} methods of |
| * {@link SortedMultiset#entrySet}, and {@link SortedMultiset#remove(Object, int)}. In many |
| * situations, you may wish to override {@link SortedMultiset#elementSet} to forward to this |
| * implementation or a subclass thereof. |
| * |
| * @since 15.0 |
| */ |
| protected class StandardElementSet extends SortedMultisets.NavigableElementSet<E> { |
| /** Constructor for use by subclasses. */ |
| public StandardElementSet() { |
| super(ForwardingSortedMultiset.this); |
| } |
| } |
| |
| @Override |
| public Comparator<? super E> comparator() { |
| return delegate().comparator(); |
| } |
| |
| @Override |
| public SortedMultiset<E> descendingMultiset() { |
| return delegate().descendingMultiset(); |
| } |
| |
| /** |
| * A skeleton implementation of a descending multiset view. Normally, {@link |
| * #descendingMultiset()} will not reflect any changes you make to the behavior of methods such as |
| * {@link #add(Object)} or {@link #pollFirstEntry}. This skeleton implementation correctly |
| * delegates each of its operations to the appropriate methods of this {@code |
| * ForwardingSortedMultiset}. |
| * |
| * <p>In many cases, you may wish to override {@link #descendingMultiset()} to return an instance |
| * of a subclass of {@code StandardDescendingMultiset}. |
| * |
| * @since 15.0 |
| */ |
| protected abstract class StandardDescendingMultiset extends DescendingMultiset<E> { |
| /** Constructor for use by subclasses. */ |
| public StandardDescendingMultiset() {} |
| |
| @Override |
| SortedMultiset<E> forwardMultiset() { |
| return ForwardingSortedMultiset.this; |
| } |
| } |
| |
| @Override |
| public Entry<E> firstEntry() { |
| return delegate().firstEntry(); |
| } |
| |
| /** |
| * A sensible definition of {@link #firstEntry()} in terms of {@code entrySet().iterator()}. |
| * |
| * <p>If you override {@link #entrySet()}, you may wish to override {@link #firstEntry()} to |
| * forward to this implementation. |
| */ |
| protected Entry<E> standardFirstEntry() { |
| Iterator<Entry<E>> entryIterator = entrySet().iterator(); |
| if (!entryIterator.hasNext()) { |
| return null; |
| } |
| Entry<E> entry = entryIterator.next(); |
| return Multisets.immutableEntry(entry.getElement(), entry.getCount()); |
| } |
| |
| @Override |
| public Entry<E> lastEntry() { |
| return delegate().lastEntry(); |
| } |
| |
| /** |
| * A sensible definition of {@link #lastEntry()} in terms of {@code |
| * descendingMultiset().entrySet().iterator()}. |
| * |
| * <p>If you override {@link #descendingMultiset} or {@link #entrySet()}, you may wish to override |
| * {@link #firstEntry()} to forward to this implementation. |
| */ |
| protected Entry<E> standardLastEntry() { |
| Iterator<Entry<E>> entryIterator = descendingMultiset().entrySet().iterator(); |
| if (!entryIterator.hasNext()) { |
| return null; |
| } |
| Entry<E> entry = entryIterator.next(); |
| return Multisets.immutableEntry(entry.getElement(), entry.getCount()); |
| } |
| |
| @Override |
| public Entry<E> pollFirstEntry() { |
| return delegate().pollFirstEntry(); |
| } |
| |
| /** |
| * A sensible definition of {@link #pollFirstEntry()} in terms of {@code entrySet().iterator()}. |
| * |
| * <p>If you override {@link #entrySet()}, you may wish to override {@link #pollFirstEntry()} to |
| * forward to this implementation. |
| */ |
| protected Entry<E> standardPollFirstEntry() { |
| Iterator<Entry<E>> entryIterator = entrySet().iterator(); |
| if (!entryIterator.hasNext()) { |
| return null; |
| } |
| Entry<E> entry = entryIterator.next(); |
| entry = Multisets.immutableEntry(entry.getElement(), entry.getCount()); |
| entryIterator.remove(); |
| return entry; |
| } |
| |
| @Override |
| public Entry<E> pollLastEntry() { |
| return delegate().pollLastEntry(); |
| } |
| |
| /** |
| * A sensible definition of {@link #pollLastEntry()} in terms of {@code |
| * descendingMultiset().entrySet().iterator()}. |
| * |
| * <p>If you override {@link #descendingMultiset()} or {@link #entrySet()}, you may wish to |
| * override {@link #pollLastEntry()} to forward to this implementation. |
| */ |
| protected Entry<E> standardPollLastEntry() { |
| Iterator<Entry<E>> entryIterator = descendingMultiset().entrySet().iterator(); |
| if (!entryIterator.hasNext()) { |
| return null; |
| } |
| Entry<E> entry = entryIterator.next(); |
| entry = Multisets.immutableEntry(entry.getElement(), entry.getCount()); |
| entryIterator.remove(); |
| return entry; |
| } |
| |
| @Override |
| public SortedMultiset<E> headMultiset(E upperBound, BoundType boundType) { |
| return delegate().headMultiset(upperBound, boundType); |
| } |
| |
| @Override |
| public SortedMultiset<E> subMultiset( |
| E lowerBound, BoundType lowerBoundType, E upperBound, BoundType upperBoundType) { |
| return delegate().subMultiset(lowerBound, lowerBoundType, upperBound, upperBoundType); |
| } |
| |
| /** |
| * A sensible definition of {@link #subMultiset(Object, BoundType, Object, BoundType)} in terms of |
| * {@link #headMultiset(Object, BoundType) headMultiset} and {@link #tailMultiset(Object, |
| * BoundType) tailMultiset}. |
| * |
| * <p>If you override either of these methods, you may wish to override {@link |
| * #subMultiset(Object, BoundType, Object, BoundType)} to forward to this implementation. |
| */ |
| protected SortedMultiset<E> standardSubMultiset( |
| E lowerBound, BoundType lowerBoundType, E upperBound, BoundType upperBoundType) { |
| return tailMultiset(lowerBound, lowerBoundType).headMultiset(upperBound, upperBoundType); |
| } |
| |
| @Override |
| public SortedMultiset<E> tailMultiset(E lowerBound, BoundType boundType) { |
| return delegate().tailMultiset(lowerBound, boundType); |
| } |
| } |