/** * 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.smscserver.message.impl; import java.util.concurrent.PriorityBlockingQueue; /** * A Specialized queue implementation to imitate an empty queue if the head of the queue is not ready to run. * * @version $Rev$ $Date$ */ public class IOSessionQueue extends PriorityBlockingQueue<MessagePoller> { private static final long serialVersionUID = -689568747117274583L; public IOSessionQueue() { super(); } /** * {@inheritDoc} * */ @Override public MessagePoller peek() { MessagePoller poller = super.peek(); // if the head of the queue is in the future we have no work to do if ((poller == null) || (poller.getNextCheckTime() > System.currentTimeMillis())) { return null; } return poller; } /** * {@inheritDoc} * */ @Override public MessagePoller poll() { Runnable runnable = this.peek(); if (runnable == null) { return null; } return super.poll(); } }