/*

 * 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.Predicate;

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

/**

 * Decorates another {@link Queue} to validate that additions

 * match a specified predicate.

 * <p>

 * This queue exists to provide validation for the decorated queue.

 * It is normally created to decorate an empty queue.

 * If an object cannot be added to the queue, an IllegalArgumentException is thrown.

 * </p>

 * <p>

 * One usage would be to ensure that no null entries are added to the queue.

 * </p>

 * <pre>Queue queue = PredicatedQueue.predicatedQueue(new UnboundedFifoQueue(), NotNullPredicate.INSTANCE);</pre>

 *

 * @param <E> the type of elements held in this queue

 * @since 4.0

 */

public class PredicatedQueue<E> extends PredicatedCollection<E> implements Queue<E> {

    /** Serialization version */

    private static final long serialVersionUID = 2307609000539943581L;

    /**

     * Factory method to create a predicated (validating) queue.

     * <p>

     * If there are any elements already in the queue being decorated, they

     * are validated.

     *

     * @param <E> the type of the elements in the queue

     * @param Queue  the queue to decorate, must not be null

     * @param predicate  the predicate to use for validation, must not be null

     * @return a new predicated queue

     * @throws NullPointerException if queue or predicate is null

     * @throws IllegalArgumentException if the queue contains invalid elements

     */

    public static <E> PredicatedQueue<E> predicatedQueue(final Queue<E> Queue,

                                                          final Predicate<? super E> predicate) {

        return new PredicatedQueue<>(Queue, predicate);

    }

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

    /**

     * Constructor that wraps (not copies).

     * <p>

     * If there are any elements already in the collection being decorated, they

     * are validated.

     *

     * @param queue  the queue to decorate, must not be null

     * @param predicate  the predicate to use for validation, must not be null

     * @throws NullPointerException if queue or predicate is null

     * @throws IllegalArgumentException if the Queue contains invalid elements

     */

    protected PredicatedQueue(final Queue<E> queue, final Predicate<? super E> predicate) {

        super(queue, predicate);

    }

    /**

     * Gets the queue being decorated.

     *

     * @return the decorated queue

     */

    @Override

    protected Queue<E> decorated() {

        return (Queue<E>) super.decorated();

    }

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

    /**

     * Override to validate the object being added to ensure it matches

     * the predicate.

     *

     * @param object  the object being added

     * @return the result of adding to the underlying queue

     * @throws IllegalArgumentException if the add is invalid

     */

    @Override

    public boolean offer(final E object) {

        validate(object);

        return decorated().offer(object);

    }

    @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();

    }

}