/*
 * 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.flink.runtime.io.disk.iomanager;

import java.io.Closeable;
import java.util.concurrent.LinkedBlockingQueue;

/**
 * A {@link LinkedBlockingQueue} that is extended with closing methods.
 */
public final class RequestQueue<E> extends LinkedBlockingQueue<E> implements Closeable {
	
	private static final long serialVersionUID = 3804115535778471680L;
	
	/** Flag marking this queue as closed. */
	private volatile boolean closed = false;
	
	/**
	 * Closes this request queue.
	 * 
	 * @see java.io.Closeable#close()
	 */
	@Override
	public void close() {
		this.closed = true;
	}
	
	/**
	 * Checks whether this request queue is closed.
	 * 
	 * @return True, if the queue is closed, false otherwise.
	 */
	public boolean isClosed() {
		return this.closed;
	}
}
