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.falcon.entity.store; import org.apache.commons.lang3.StringUtils; import org.apache.falcon.FalconException; import org.apache.falcon.entity.FeedHelper; import org.apache.falcon.entity.v0.Entity; import org.apache.falcon.entity.v0.EntityType; import org.apache.falcon.entity.v0.feed.Cluster; import org.apache.falcon.entity.v0.feed.Feed; import org.apache.falcon.entity.v0.feed.Location; import org.apache.falcon.resource.FeedLookupResult; import org.apache.falcon.service.ConfigurationChangeListener; import org.apache.falcon.util.DeploymentUtil; import org.apache.falcon.util.FalconRadixUtils; import org.apache.falcon.util.RadixTree; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.util.Collection; import java.util.List; /** * A <Key, Value> Store to store FeedProperties against Feed's Locations. * * For example: * let's say a feed - <b>MyFeed</b>, is configured for two clusters - cluster1 and cluster2 and has data location as * below. * /projects/myprocess/data/${MONTH}-${DAY}-${HOUR} * /projects/myprocess/meta/${MONTH}-${DAY}-${HOUR} * * then the key,value store will be like below * key1: /projects/myprocess/data/${MONTH}-${DAY}-${HOUR} * value1: [FeedProperties("cluster1", LocationType.DATA, "MyFeed"), * FeedProperties("cluster2", LocationType.DATA, "MyFeed") * ] * * key2: /projects/myprocess/meta/${MONTH}-${DAY}-${HOUR} * value2: [FeedProperties("cluster1", LocationType.META, "MyFeed"), * FeedProperties("cluster2", LocationType.META, "MyFeed") * ] * * It ensures that no two Feeds share the same location. * It can also be used for operations like: * <ul> * <li>Find if a there is a feed which uses a given path as it's location.</li> * <li>Find name of the feed, given it's location.</li> * </ul> */ public final class FeedLocationStore implements ConfigurationChangeListener { private static final Logger LOG = LoggerFactory.getLogger(FeedLocationStore.class); protected final FeedPathStore<FeedLookupResult.FeedProperties> store = new RadixTree<FeedLookupResult.FeedProperties>(); private static FeedLocationStore instance = new FeedLocationStore(); private FeedLocationStore() { } public static FeedLocationStore get() { return instance; } @Override public void onAdd(Entity entity) throws FalconException { if (entity.getEntityType() == EntityType.FEED) { Feed feed = (Feed) entity; List<Cluster> clusters = feed.getClusters().getClusters(); for (Cluster cluster : clusters) { if (DeploymentUtil.getCurrentClusters().contains(cluster.getName())) { List<Location> clusterSpecificLocations = FeedHelper .getLocations(FeedHelper.getCluster(feed, cluster.getName()), feed); if (clusterSpecificLocations != null) { for (Location location : clusterSpecificLocations) { if (location != null && StringUtils.isNotBlank(location.getPath())) { FeedLookupResult.FeedProperties value = new FeedLookupResult.FeedProperties( feed.getName(), location.getType(), cluster.getName()); store.insert(StringUtils.trim(location.getPath()), value); LOG.debug("Inserted location: {} for feed: {} and cluster: {}", location.getPath(), feed.getName(), cluster.getName()); } } } } } } } /** * Delete the key(path) from the store if the feed is deleted. * @param entity entity object * @throws FalconException */ @Override public void onRemove(Entity entity) throws FalconException { if (entity.getEntityType() == EntityType.FEED) { Feed feed = (Feed) entity; List<Cluster> clusters = feed.getClusters().getClusters(); for (Cluster cluster : clusters) { List<Location> clusterSpecificLocations = FeedHelper .getLocations(FeedHelper.getCluster(feed, cluster.getName()), feed); if (clusterSpecificLocations != null) { for (Location location : clusterSpecificLocations) { if (location != null && StringUtils.isNotBlank(location.getPath())) { FeedLookupResult.FeedProperties value = new FeedLookupResult.FeedProperties( feed.getName(), location.getType(), cluster.getName()); LOG.debug("Delete called for location: {} for feed: {} and cluster: {}", location.getPath(), feed.getName(), cluster.getName()); store.delete(location.getPath(), value); LOG.debug("Deleted location: {} for feed: {} and cluster: {}", location.getPath(), feed.getName(), cluster.getName()); } } } } } } /** * Delete the old path and insert the new Path when the feed is updated. * @param oldEntity old entity object * @param newEntity updated entity object * @throws FalconException if the new path already exists in the store. */ @Override public void onChange(Entity oldEntity, Entity newEntity) throws FalconException { onRemove(oldEntity); onAdd(newEntity); } @Override public void onReload(Entity entity) throws FalconException { onAdd(entity); } public Collection<FeedLookupResult.FeedProperties> reverseLookup(String path) { return store.find(path, new FalconRadixUtils.FeedRegexAlgorithm()); } }