| package org.apache.commons.jcs.engine; |
| |
| /* |
| * 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. |
| */ |
| |
| import java.io.IOException; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.concurrent.ConcurrentLinkedQueue; |
| |
| import org.apache.commons.jcs.engine.behavior.ICacheElement; |
| import org.apache.commons.jcs.engine.behavior.ICacheServiceNonLocal; |
| import org.apache.commons.jcs.log.Log; |
| import org.apache.commons.jcs.log.LogManager; |
| import org.apache.commons.jcs.utils.timing.ElapsedTimer; |
| |
| /** |
| * Zombie adapter for the non local cache services. It just balks if there is no queue configured. |
| * <p> |
| * If a queue is configured, then events will be added to the queue. The idea is that when proper |
| * operation is restored, the non local cache will walk the queue. The queue must be bounded so it |
| * does not eat memory. |
| * <p> |
| * This originated in the remote cache. |
| */ |
| public class ZombieCacheServiceNonLocal<K, V> |
| extends ZombieCacheService<K, V> |
| implements ICacheServiceNonLocal<K, V> |
| { |
| /** The logger */ |
| private static final Log log = LogManager.getLog( ZombieCacheServiceNonLocal.class ); |
| |
| /** How big can the queue grow. */ |
| private int maxQueueSize = 0; |
| |
| /** The queue */ |
| private final ConcurrentLinkedQueue<ZombieEvent> queue; |
| |
| /** |
| * Default. |
| */ |
| public ZombieCacheServiceNonLocal() |
| { |
| queue = new ConcurrentLinkedQueue<>(); |
| } |
| |
| /** |
| * Sets the maximum number of items that will be allowed on the queue. |
| * <p> |
| * @param maxQueueSize |
| */ |
| public ZombieCacheServiceNonLocal( int maxQueueSize ) |
| { |
| this.maxQueueSize = maxQueueSize; |
| queue = new ConcurrentLinkedQueue<>(); |
| } |
| |
| /** |
| * Gets the number of items on the queue. |
| * <p> |
| * @return size of the queue. |
| */ |
| public int getQueueSize() |
| { |
| return queue.size(); |
| } |
| |
| private void addQueue(ZombieEvent event) |
| { |
| queue.add(event); |
| if (queue.size() > maxQueueSize) |
| { |
| queue.poll(); // drop oldest entry |
| } |
| } |
| |
| /** |
| * Adds an update event to the queue if the maxSize is greater than 0; |
| * <p> |
| * @param item ICacheElement |
| * @param listenerId - identifies the caller. |
| */ |
| @Override |
| public void update( ICacheElement<K, V> item, long listenerId ) |
| { |
| if ( maxQueueSize > 0 ) |
| { |
| PutEvent<K, V> event = new PutEvent<>( item, listenerId ); |
| addQueue( event ); |
| } |
| // Zombies have no inner life |
| } |
| |
| /** |
| * Adds a removeAll event to the queue if the maxSize is greater than 0; |
| * <p> |
| * @param cacheName - region name |
| * @param key - item key |
| * @param listenerId - identifies the caller. |
| */ |
| @Override |
| public void remove( String cacheName, K key, long listenerId ) |
| { |
| if ( maxQueueSize > 0 ) |
| { |
| RemoveEvent<K> event = new RemoveEvent<>( cacheName, key, listenerId ); |
| addQueue( event ); |
| } |
| // Zombies have no inner life |
| } |
| |
| /** |
| * Adds a removeAll event to the queue if the maxSize is greater than 0; |
| * <p> |
| * @param cacheName - name of the region |
| * @param listenerId - identifies the caller. |
| */ |
| @Override |
| public void removeAll( String cacheName, long listenerId ) |
| { |
| if ( maxQueueSize > 0 ) |
| { |
| RemoveAllEvent event = new RemoveAllEvent( cacheName, listenerId ); |
| addQueue( event ); |
| } |
| // Zombies have no inner life |
| } |
| |
| /** |
| * Does nothing. Gets are synchronous and cannot be added to a queue. |
| * <p> |
| * @param cacheName - region name |
| * @param key - item key |
| * @param requesterId - identifies the caller. |
| * @return null |
| * @throws IOException |
| */ |
| @Override |
| public ICacheElement<K, V> get( String cacheName, K key, long requesterId ) |
| throws IOException |
| { |
| // Zombies have no inner life |
| return null; |
| } |
| |
| /** |
| * Does nothing. |
| * <p> |
| * @param cacheName |
| * @param pattern |
| * @param requesterId |
| * @return empty map |
| * @throws IOException |
| */ |
| @Override |
| public Map<K, ICacheElement<K, V>> getMatching( String cacheName, String pattern, long requesterId ) |
| throws IOException |
| { |
| return Collections.emptyMap(); |
| } |
| |
| /** |
| * @param cacheName - region name |
| * @param keys - item key |
| * @param requesterId - identity of the caller |
| * @return an empty map. zombies have no internal data |
| */ |
| @Override |
| public Map<K, ICacheElement<K, V>> getMultiple( String cacheName, Set<K> keys, long requesterId ) |
| { |
| return new HashMap<>(); |
| } |
| |
| /** |
| * Does nothing. |
| * <p> |
| * @param cacheName - region name |
| * @return empty set |
| */ |
| @Override |
| public Set<K> getKeySet( String cacheName ) |
| { |
| return Collections.emptySet(); |
| } |
| |
| /** |
| * Walk the queue, calling the service for each queue operation. |
| * <p> |
| * @param service |
| * @throws Exception |
| */ |
| public synchronized void propagateEvents( ICacheServiceNonLocal<K, V> service ) |
| throws Exception |
| { |
| int cnt = 0; |
| log.info( "Propagating events to the new ICacheServiceNonLocal." ); |
| ElapsedTimer timer = new ElapsedTimer(); |
| while ( !queue.isEmpty() ) |
| { |
| cnt++; |
| |
| // for each item, call the appropriate service method |
| ZombieEvent event = queue.poll(); |
| |
| if ( event instanceof PutEvent ) |
| { |
| @SuppressWarnings("unchecked") // Type checked by instanceof |
| PutEvent<K, V> putEvent = (PutEvent<K, V>) event; |
| service.update( putEvent.element, event.requesterId ); |
| } |
| else if ( event instanceof RemoveEvent ) |
| { |
| @SuppressWarnings("unchecked") // Type checked by instanceof |
| RemoveEvent<K> removeEvent = (RemoveEvent<K>) event; |
| service.remove( event.cacheName, removeEvent.key, event.requesterId ); |
| } |
| else if ( event instanceof RemoveAllEvent ) |
| { |
| service.removeAll( event.cacheName, event.requesterId ); |
| } |
| } |
| log.info( "Propagated {0} events to the new ICacheServiceNonLocal in {1}", |
| cnt, timer.getElapsedTimeString() ); |
| } |
| |
| /** |
| * Base of the other events. |
| */ |
| protected static abstract class ZombieEvent |
| { |
| /** The name of the region. */ |
| String cacheName; |
| |
| /** The id of the requester */ |
| long requesterId; |
| } |
| |
| /** |
| * A basic put event. |
| */ |
| private static class PutEvent<K, V> |
| extends ZombieEvent |
| { |
| /** The element to put */ |
| ICacheElement<K, V> element; |
| |
| /** |
| * Set the element |
| * @param element |
| * @param requesterId |
| */ |
| public PutEvent( ICacheElement<K, V> element, long requesterId ) |
| { |
| this.requesterId = requesterId; |
| this.element = element; |
| } |
| } |
| |
| /** |
| * A basic Remove event. |
| */ |
| private static class RemoveEvent<K> |
| extends ZombieEvent |
| { |
| /** The key to remove */ |
| K key; |
| |
| /** |
| * Set the element |
| * @param cacheName |
| * @param key |
| * @param requesterId |
| */ |
| public RemoveEvent( String cacheName, K key, long requesterId ) |
| { |
| this.cacheName = cacheName; |
| this.requesterId = requesterId; |
| this.key = key; |
| } |
| } |
| |
| /** |
| * A basic RemoveAll event. |
| */ |
| private static class RemoveAllEvent |
| extends ZombieEvent |
| { |
| /** |
| * @param cacheName |
| * @param requesterId |
| */ |
| public RemoveAllEvent( String cacheName, long requesterId ) |
| { |
| this.cacheName = cacheName; |
| this.requesterId = requesterId; |
| } |
| } |
| } |