Java tutorial
/* * (C) Copyright 2013 Nuxeo SA (http://nuxeo.com/) and contributors. * * All rights reserved. This program and the accompanying materials * are made available under the terms of the GNU Lesser General Public License * (LGPL) version 2.1 which accompanies this distribution, and is available at * http://www.gnu.org/licenses/lgpl-2.1.html * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * Contributors: * Florent Guillaume */ package org.nuxeo.ecm.core.redis.contribs; import java.io.IOException; import java.util.concurrent.BlockingQueue; import java.util.concurrent.TimeUnit; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.nuxeo.ecm.core.work.NuxeoBlockingQueue; import org.nuxeo.ecm.core.work.WorkHolder; import org.nuxeo.ecm.core.work.api.Work; /** * Redis-based {@link BlockingQueue}. * <p> * It has unlimited capacity, so never blocks on {@link #put} and * {@link #offer} always returns {@code true}. * * @since 5.8 */ public class RedisBlockingQueue extends NuxeoBlockingQueue { private static final Log log = LogFactory.getLog(RedisBlockingQueue.class); protected final String queueId; protected final RedisWorkQueuing queuing; public RedisBlockingQueue(String queueId, RedisWorkQueuing queuing) { this.queueId = queueId; this.queuing = queuing; } @Override public int getQueueSize() { return queuing.getScheduledSize(queueId); } @Override public Runnable take() throws InterruptedException { for (;;) { Runnable r = poll(1, TimeUnit.DAYS); if (r != null) { return r; } } } @Override public Runnable poll(long timeout, TimeUnit unit) throws InterruptedException { long nanos = unit.toNanos(timeout); nanos = awaitActivation(nanos); if (nanos <= 0) { return null; } long end = System.currentTimeMillis() + TimeUnit.NANOSECONDS.toMillis(nanos); for (;;) { Runnable r = poll(); if (r != null) { return r; } if (timeUntil(end) == 0) { return null; } // TODO replace by wakeup when an element is added Thread.sleep(100); } } @Override public void putElement(Runnable r) { Work work = WorkHolder.getWork(r); try { queuing.addScheduledWork(queueId, work); } catch (IOException e) { log.error("Failed to add Work: " + work, e); throw new RuntimeException(e); } } @Override public Runnable pollElement() { try { Work work = queuing.removeScheduledWork(queueId); if (work != null) { log.debug("Remove scheduled " + work); } return work == null ? null : new WorkHolder(work); } catch (IOException e) { log.error("Failed to remove Work from queue: " + queueId, e); throw new RuntimeException(e); } } }