| /* |
| * 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.cache.query; |
| |
| import org.apache.geode.cache.CacheCallback; |
| |
| /** |
| * Application plug-in interface for handling continuous query events after they occur. The listener |
| * has two methods, one that is called when there is an event satisfied by the CQ and the other |
| * called when there is an error during CQ processing. |
| * |
| * @since GemFire 5.5 |
| */ |
| |
| public interface CqListener extends CacheCallback { |
| |
| /** |
| * This method is invoked when an event is occurred on the region that satisfied the query |
| * condition of this CQ. This event does not contain an error. If CQ is executed using |
| * ExecuteWithInitialResults the returned result may already include the changes with respect to |
| * this event. This could arise when updates are happening on the region while CQ registration is |
| * in progress. The CQ does not block any region operation as it could affect the performance of |
| * region operation. Its up to the application to synchronize between the region operation and CQ |
| * registration to avoid duplicate event being delivered. |
| * |
| * @see org.apache.geode.cache.query.CqQuery#executeWithInitialResults |
| */ |
| void onEvent(CqEvent aCqEvent); |
| |
| /** |
| * This method is invoked when there is an error during CQ processing. The error can appear while |
| * applying query condition on the event. e.g if the event doesn't has attributes as specified in |
| * the CQ query. This event does contain an error. The newValue may or may not be available, and |
| * will be null if not available. |
| */ |
| void onError(CqEvent aCqEvent); |
| } |