Java tutorial
/* * 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.sling.distribution.queue.impl.simple; import javax.annotation.Nonnull; import java.io.File; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.FilenameFilter; import java.util.Collection; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import org.apache.commons.io.IOUtils; import org.apache.commons.io.LineIterator; import org.apache.sling.commons.json.JSONArray; import org.apache.sling.commons.json.JSONException; import org.apache.sling.commons.json.JSONObject; import org.apache.sling.commons.json.JSONTokener; import org.apache.sling.commons.scheduler.ScheduleOptions; import org.apache.sling.commons.scheduler.Scheduler; import org.apache.sling.distribution.queue.DistributionQueue; import org.apache.sling.distribution.queue.DistributionQueueItem; import org.apache.sling.distribution.queue.DistributionQueueProcessor; import org.apache.sling.distribution.queue.DistributionQueueProvider; import org.apache.sling.distribution.queue.DistributionQueueType; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * a queue provider {@link org.apache.sling.distribution.queue.DistributionQueueProvider} for simple in memory * {@link org.apache.sling.distribution.queue.DistributionQueue}s */ public class SimpleDistributionQueueProvider implements DistributionQueueProvider { public static final String TYPE = "simple"; public static final String TYPE_CHECKPOINT = "simple-checkpoint"; private final Logger log = LoggerFactory.getLogger(getClass()); private final String name; private final Scheduler scheduler; private final Map<String, SimpleDistributionQueue> queueMap = new ConcurrentHashMap<String, SimpleDistributionQueue>(); private final boolean checkpoint; private File checkpointDirectory; public SimpleDistributionQueueProvider(Scheduler scheduler, String name, boolean checkpoint) { this.checkpoint = checkpoint; if (name == null || scheduler == null) { throw new IllegalArgumentException("all arguments are required"); } if (checkpoint) { this.checkpointDirectory = new File(name + "-simple-queues-checkpoints"); log.info("creating checkpoint directory {}", checkpointDirectory.getAbsoluteFile()); if (checkpointDirectory.exists() && !checkpointDirectory.isDirectory()) { assert checkpointDirectory.delete(); } boolean created = false; if (!checkpointDirectory.exists()) { created = checkpointDirectory.mkdir(); } log.info("checkpoint directory created: {}, exists {}", created, checkpointDirectory.isDirectory() && checkpointDirectory.exists()); } this.scheduler = scheduler; this.name = name; } @Nonnull public DistributionQueue getQueue(@Nonnull String queueName) { String key = name + queueName; SimpleDistributionQueue queue = queueMap.get(key); if (queue == null) { log.debug("creating a queue with key {}", key); queue = new SimpleDistributionQueue(name, queueName); queueMap.put(key, queue); log.debug("queue created {}", queue); } return queue; } @Override public DistributionQueue getQueue(@Nonnull String queueName, @Nonnull DistributionQueueType type) { return getQueue(queueName); } Collection<SimpleDistributionQueue> getQueues() { return queueMap.values(); } public void enableQueueProcessing(@Nonnull DistributionQueueProcessor queueProcessor, String... queueNames) { if (checkpoint) { // recover from checkpoints log.debug("recovering from checkpoints if needed"); for (final String queueName : queueNames) { log.debug("recovering for queue {}", queueName); DistributionQueue queue = getQueue(queueName); FilenameFilter filenameFilter = new FilenameFilter() { @Override public boolean accept(File file, String name) { return name.equals(queueName + "-checkpoint"); } }; for (File qf : checkpointDirectory.listFiles(filenameFilter)) { log.info("recovering from checkpoint {}", qf); try { LineIterator lineIterator = IOUtils.lineIterator(new FileReader(qf)); while (lineIterator.hasNext()) { String s = lineIterator.nextLine(); String[] split = s.split(" "); String id = split[0]; String infoString = split[1]; Map<String, Object> info = new HashMap<String, Object>(); JSONTokener jsonTokener = new JSONTokener(infoString); JSONObject jsonObject = new JSONObject(jsonTokener); Iterator<String> keys = jsonObject.keys(); while (keys.hasNext()) { String key = keys.next(); JSONArray v = jsonObject.optJSONArray(key); if (v != null) { String[] a = new String[v.length()]; for (int i = 0; i < a.length; i++) { a[i] = v.getString(i); } info.put(key, a); } else { info.put(key, jsonObject.getString(key)); } } queue.add(new DistributionQueueItem(id, info)); } log.info("recovered {} items from queue {}", queue.getStatus().getItemsCount(), queueName); } catch (FileNotFoundException e) { log.warn("could not read checkpoint file {}", qf.getAbsolutePath()); } catch (JSONException e) { log.warn("could not parse info from checkpoint file {}", qf.getAbsolutePath()); } } } // enable checkpointing for (String queueName : queueNames) { ScheduleOptions options = scheduler.NOW(-1, 15).canRunConcurrently(false) .name(getJobName(queueName + "-checkpoint")); scheduler.schedule(new SimpleDistributionQueueCheckpoint(getQueue(queueName), checkpointDirectory), options); } } // enable processing for (String queueName : queueNames) { ScheduleOptions options = scheduler.NOW(-1, 1).canRunConcurrently(false).name(getJobName(queueName)); scheduler.schedule(new SimpleDistributionQueueProcessor(getQueue(queueName), queueProcessor), options); } } public void disableQueueProcessing() { for (DistributionQueue queue : getQueues()) { String queueName = queue.getName(); // disable queue processing if (scheduler.unschedule(getJobName(queueName))) { log.debug("queue processing on {} stopped", queue); } else { log.warn("could not disable queue processing on {}", queue); } if (checkpoint) { // disable checkpointing if (scheduler.unschedule(getJobName(queueName) + "-checkpoint")) { log.debug("checkpoint on {} stopped", queue); } else { log.warn("could not disable checkpoint on {}", queue); } } } } private String getJobName(String queueName) { return "simple-queueProcessor-" + name + "-" + queueName; } }