Java tutorial
/** * Copyright 2005-2014 Red Hat, Inc. * * Red Hat 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 io.fabric8.partition.internal.repositories; import com.google.common.base.Charsets; import com.google.common.collect.Lists; import com.google.common.io.Resources; import io.fabric8.api.FabricException; import io.fabric8.partition.internal.BaseWorkItemRepository; import io.fabric8.partition.internal.functions.ChildDataToPath; import io.fabric8.zookeeper.utils.ZooKeeperUtils; import org.apache.curator.framework.CuratorFramework; import org.apache.curator.framework.recipes.cache.ChildData; import org.apache.curator.framework.recipes.cache.PathChildrenCache; import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent; import org.apache.curator.framework.recipes.cache.PathChildrenCacheListener; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.net.URL; import java.util.List; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.TimeUnit; public class ZkWorkItemRepository extends BaseWorkItemRepository implements PathChildrenCacheListener { private static final Logger LOGGER = LoggerFactory.getLogger(ZkWorkItemRepository.class); private final ExecutorService executorService = Executors.newSingleThreadExecutor(); private final String partitionsPath; private final CuratorFramework curator; private volatile PathChildrenCache partitionCache; public ZkWorkItemRepository(CuratorFramework curator, String partitionsPath) { this.partitionsPath = partitionsPath; this.curator = curator; } @Override public synchronized void start() { try { ZooKeeperUtils.createDefault(curator, partitionsPath, null); if (partitionCache == null) { partitionCache = new PathChildrenCache(curator, partitionsPath, true, false, executorService); partitionCache.getListenable().addListener(this); partitionCache.start(PathChildrenCache.StartMode.POST_INITIALIZED_EVENT); partitionCache.rebuild(); } } catch (Exception e) { throw FabricException.launderThrowable(e); } } @Override public synchronized void stop() { if (partitionCache != null) { try { partitionCache.close(); partitionCache = null; } catch (IOException e) { throw FabricException.launderThrowable(e); } } } @Override public void close() { stop(); executorService.shutdownNow(); } @Override public List<String> listWorkItemLocations() { List<ChildData> children = partitionCache.getCurrentData(); return Lists.transform(children, ChildDataToPath.INSTANCE); } @Override public String readContent(String location) { try { return Resources.toString(new URL(ZkWorkItemRepositoryFactory.SCHEME + ":" + location), Charsets.UTF_8); } catch (Exception e) { throw FabricException.launderThrowable(e); } } @Override public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception { switch (event.getType()) { case INITIALIZED: case CHILD_ADDED: case CHILD_REMOVED: notifyListeners(); break; } } }