/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.commons.collections4.queue;

import java.util.Queue;

import org.apache.commons.collections4.collection.AbstractCollectionDecorator;

Decorates another Queue to provide additional behaviour. 

Methods are forwarded directly to the decorated queue.


This implementation does not forward the hashCode and equals methods through
to the backing object, but relies on Object's implementation. This is
necessary as some Queue implementations, e.g. LinkedList, have custom a
equals implementation for which symmetry can not be preserved.
See class javadoc of AbstractCollectionDecorator for more information.

Type parameters:
<E> – the type of the elements in the queue
Since:
4.0/**
 * Decorates another {@link Queue} to provide additional behaviour.
 * <p>
 * Methods are forwarded directly to the decorated queue.
 * </p>
 * <p>
 * This implementation does not forward the hashCode and equals methods through
 * to the backing object, but relies on Object's implementation. This is
 * necessary as some Queue implementations, e.g. LinkedList, have custom a
 * equals implementation for which symmetry can not be preserved.
 * See class javadoc of AbstractCollectionDecorator for more information.
 * </p>
 *
 * @param <E> the type of the elements in the queue
 * @since 4.0
 */
public abstract class AbstractQueueDecorator<E> extends AbstractCollectionDecorator<E>
        implements Queue<E> {

    
Serialization version /** Serialization version */
    private static final long serialVersionUID = -2629815475789577029L;

    
Constructor only used in deserialization, do not use otherwise.
/**
     * Constructor only used in deserialization, do not use otherwise.
     */
    protected AbstractQueueDecorator() {
        super();
    }

    
Constructor that wraps (not copies).
Params:
queue –  the queue to decorate, must not be null
Throws:
NullPointerException – if queue is null/**
     * Constructor that wraps (not copies).
     *
     * @param queue  the queue to decorate, must not be null
     * @throws NullPointerException if queue is null
     */
    protected AbstractQueueDecorator(final Queue<E> queue) {
        super(queue);
    }

    
Gets the queue being decorated.
Returns:
the decorated queue/**
     * Gets the queue being decorated.
     *
     * @return the decorated queue
     */
    @Override
    protected Queue<E> decorated() {
        return (Queue<E>) super.decorated();
    }

    //-----------------------------------------------------------------------

    @Override
    public boolean offer(final E obj) {
        return decorated().offer(obj);
    }

    @Override
    public E poll() {
        return decorated().poll();
    }

    @Override
    public E peek() {
        return decorated().peek();
    }

    @Override
    public E element() {
        return decorated().element();
    }

    @Override
    public E remove() {
        return decorated().remove();
    }

}