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 import net.sf.ehcache.search.Attribute;
20
21 /***
22 * Helper class to construct the builtin aggregator types. These methods can be statically imported to make query building looker better in
23 * source code
24 *
25 * @author teck
26 */
27 public final class Aggregators {
28
29 private Aggregators() {
30
31 }
32
33 /***
34 * Construct a minimum value aggregator
35 *
36 * @param attribute
37 * @return min aggregator
38 */
39 public static Aggregator min(final Attribute<?> attribute) {
40 return new Aggregator() {
41 public <T> AggregatorInstance<T> createInstance() {
42 return new Min(attribute);
43 }
44 };
45 }
46
47 /***
48 * Construct a maximum value aggregator
49 *
50 * @param attribute
51 * @return max aggregator
52 */
53 public static Aggregator max(final Attribute<?> attribute) {
54 return new Aggregator() {
55 public <T> AggregatorInstance<T> createInstance() {
56 return new Max(attribute);
57 }
58 };
59 }
60
61 /***
62 * Construct an average value aggregator
63 *
64 * @param attribute
65 * @return average aggregator
66 */
67 public static Aggregator average(final Attribute<?> attribute) {
68 return new Aggregator() {
69 public AggregatorInstance<Double> createInstance() {
70 return new Average(attribute);
71 }
72 };
73 }
74
75 /***
76 * Construct a sum aggregator
77 *
78 * @param attribute
79 * @return sum aggregator
80 */
81 public static Aggregator sum(final Attribute<?> attribute) {
82 return new Aggregator() {
83 public AggregatorInstance<Long> createInstance() {
84 return new Sum(attribute);
85 }
86 };
87 }
88
89 /***
90 * Construct a counting aggregator
91 *
92 * @return count aggregator
93 */
94 public static Aggregator count() {
95 return new Aggregator() {
96 public AggregatorInstance<Integer> createInstance() {
97 return new Count();
98 }
99 };
100
101 }
102 }