| /* |
| * 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.geode.internal.cache; |
| |
| import org.apache.geode.cache.CacheLoader; |
| import org.apache.geode.cache.CacheLoaderException; |
| import org.apache.geode.cache.LoaderHelper; |
| import org.apache.geode.cache.Region; |
| import org.apache.geode.cache.TimeoutException; |
| |
| /** |
| * Provides a set of APIs to help the implementation of the <code>CacheLoader</code> load method. An |
| * instance of <code>LoaderHelper</code> is only valid within the |
| * {@link CacheLoader#load(LoaderHelper) load} method. |
| * |
| * |
| * @see CacheLoader#load(LoaderHelper) load |
| * @since GemFire 2.0 |
| */ |
| public class LoaderHelperImpl implements LoaderHelper { |
| /** |
| * The message issued when the user attempts to netSearch on a LOCAL Region. It is public for |
| * testing purposes only. |
| */ |
| public static final String NET_SEARCH_LOCAL = |
| "Cannot netSearch for a Scope.LOCAL object"; |
| |
| private final Object key; |
| private final boolean netSearchAllowed; |
| private final boolean netLoadAllowed; |
| private final Region region; |
| private final Object aCallbackArgument; |
| private SearchLoadAndWriteProcessor searcher = null; |
| |
| |
| public LoaderHelperImpl(Region region, Object key, Object aCallbackArgument, |
| boolean netSearchAllowed, SearchLoadAndWriteProcessor searcher) { |
| this.region = region; |
| this.key = key; |
| this.aCallbackArgument = aCallbackArgument; |
| this.netSearchAllowed = netSearchAllowed; |
| this.netLoadAllowed = true; |
| this.searcher = searcher; |
| } |
| |
| public LoaderHelperImpl(Region region, Object key, Object aCallbackArgument, |
| boolean netSearchAllowed, boolean netLoadAllowed, SearchLoadAndWriteProcessor searcher) { |
| this.region = region; |
| this.key = key; |
| this.aCallbackArgument = aCallbackArgument; |
| this.netSearchAllowed = netSearchAllowed; |
| this.netLoadAllowed = netLoadAllowed; |
| this.searcher = searcher; |
| } |
| |
| |
| |
| /** |
| * Searchs other caches for the value to be loaded. If the cache is part of a distributed caching |
| * system, <code>netSearch</code> will try to locate the requested value in any other cache within |
| * the system. If the search is successful, a reference to a local copy of the value is returned. |
| * If there is no value for this entry present in the system, and doNetLoad is true, GemFire looks |
| * for and invokes <code>CacheLoaders</code> in other nodes in the system. The net load will |
| * invoke one loader at a time until a loader either returns a non-null value, or throws an |
| * exception. If the object is not found <code>null</code> is returned. |
| * |
| * @param doNetLoad if true, and there is no valid value found for this entry in the system, then |
| * look for and invoke loaders on other nodes. |
| * @return the requested value or null if not found |
| * @throws TimeoutException if the netSearch times out before getting a response from another |
| * cache |
| */ |
| @Override |
| public Object netSearch(final boolean doNetLoad) throws CacheLoaderException, TimeoutException { |
| |
| if (this.region.getAttributes().getScope().isLocal()) { |
| throw new CacheLoaderException(NET_SEARCH_LOCAL); |
| } |
| |
| boolean removeSearcher = false; |
| if (searcher == null) { |
| searcher = SearchLoadAndWriteProcessor.getProcessor(); |
| removeSearcher = true; |
| } |
| |
| try { |
| if (removeSearcher) { |
| searcher.initialize((LocalRegion) this.region, this.key, this.aCallbackArgument); |
| } |
| Object obj = null; |
| |
| if (this.netSearchAllowed) { |
| obj = searcher.doNetSearch(); |
| if (searcher.resultIsSerialized()) { |
| obj = EntryEventImpl.deserialize((byte[]) obj); |
| } |
| } |
| if (doNetLoad && obj == null && this.netLoadAllowed) { |
| obj = searcher.doNetLoad(); |
| if (searcher.resultIsSerialized()) { |
| obj = EntryEventImpl.deserialize((byte[]) obj); |
| } |
| } |
| // Note it is possible for netsearch to not be allowed |
| // but netload to be allowed. |
| // For example on replicated regions we say don't bother netsearching |
| // but we do need to check for netLoaders |
| return obj; |
| } finally { |
| if (removeSearcher) { |
| searcher.remove(); |
| } |
| } |
| } |
| |
| /** |
| * Returns the key for the value being loaded. |
| * |
| * @return The name Object for the object being loaded. |
| * @see CacheLoader#load(LoaderHelper) load |
| */ |
| @Override |
| public Object getKey() { |
| return this.key; |
| } |
| |
| /** |
| * Returns the region to which the entry belongs. |
| * |
| * @return The name of the region for the object being loaded. |
| * @see CacheLoader#load(LoaderHelper) load |
| */ |
| @Override |
| public Region getRegion() { |
| return region; |
| } |
| |
| /** |
| * Return the argument object for the load method that was passed in from application code. This |
| * object is passed in as <i>aLoaderArgument</i> in {@link Region#get(Object, Object) get}. |
| * |
| * @return the argument or null if one was not supplied |
| */ |
| @Override |
| public Object getArgument() { |
| return aCallbackArgument; |
| } |
| |
| @Override |
| public String toString() { |
| return "LoaderHelper region: " + getRegion() + " key: " + getKey() + " argument: " |
| + getArgument(); |
| } |
| } |