1 /***
2 * Copyright 2003-2010 Terracotta, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package net.sf.ehcache.search.aggregator;
18
19 /***
20 * An Aggregator describes a requested aggregation for a query and provides aggregator instances for execution
21 *
22 * @author teck
23 */
24 public interface Aggregator {
25
26 /***
27 * Create an instance of this aggregator. Every query execution will use a unique instance for requested aggregator
28 *
29 * @param <T>
30 * @return aggregator instance
31 */
32 <T> AggregatorInstance<T> createInstance();
33
34 }