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/*
* Copyright (C) 2012 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 java.util.Deque;
import java.util.Iterator;
/**
* A deque which forwards all its method calls to another deque. Subclasses
* should override one or more methods to modify the behavior of the backing
* deque as desired per the <a
* href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
*
* <p><b>Warning:</b> The methods of {@code ForwardingDeque} forward
* <b>indiscriminately</b> to the methods of the delegate. For example,
* overriding {@link #add} alone <b>will not</b> change the behavior of {@link
* #offer} which can lead to unexpected behavior. In this case, you should
* override {@code offer} as well, either providing your own implementation, or
* delegating to the provided {@code standardOffer} method.
*
* <p>The {@code standard} methods are not guaranteed to be thread-safe, even
* when all of the methods that they depend on are thread-safe.
*
* @author Kurt Alfred Kluever
* @since 12.0
*/
@Beta
public abstract class ForwardingDeque<E> extends ForwardingQueue<E>
implements Deque<E> {
/** Constructor for use by subclasses. */
protected ForwardingDeque() {}
@Override protected abstract Deque<E> delegate();
@Override
public void addFirst(E e) {
delegate().addFirst(e);
}
@Override
public void addLast(E e) {
delegate().addLast(e);
}
@Override
public Iterator<E> descendingIterator() {
return delegate().descendingIterator();
}
@Override
public E getFirst() {
return delegate().getFirst();
}
@Override
public E getLast() {
return delegate().getLast();
}
@Override
public boolean offerFirst(E e) {
return delegate().offerFirst(e);
}
@Override
public boolean offerLast(E e) {
return delegate().offerLast(e);
}
@Override
public E peekFirst() {
return delegate().peekFirst();
}
@Override
public E peekLast() {
return delegate().peekLast();
}
@Override
public E pollFirst() {
return delegate().pollFirst();
}
@Override
public E pollLast() {
return delegate().pollLast();
}
@Override
public E pop() {
return delegate().pop();
}
@Override
public void push(E e) {
delegate().push(e);
}
@Override
public E removeFirst() {
return delegate().removeFirst();
}
@Override
public E removeLast() {
return delegate().removeLast();
}
@Override
public boolean removeFirstOccurrence(Object o) {
return delegate().removeFirstOccurrence(o);
}
@Override
public boolean removeLastOccurrence(Object o) {
return delegate().removeLastOccurrence(o);
}
}
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