| /* |
| * 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; |
| |
| /** |
| * Behavior of a user-defined aggregator. Aggregates values and returns a result. In addition to the |
| * methods in the interface, implementing classes must have a 0-arg public constructor. |
| */ |
| public interface Aggregator { |
| |
| /** |
| * Initialize the Aggregator |
| */ |
| void init(); |
| |
| /** |
| * Accumulate the next scalar value |
| */ |
| void accumulate(Object value); |
| |
| /** |
| * Finish the aggregation and return the operation result. |
| * |
| * @return Return the result scalar value |
| */ |
| Object terminate(); |
| } |