1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.functor.core.algorithm;
18
19 import java.io.Serializable;
20
21 import org.apache.commons.functor.BinaryPredicate;
22 import org.apache.commons.functor.UnaryPredicate;
23 import org.apache.commons.functor.UnaryProcedure;
24 import org.apache.commons.functor.generator.Generator;
25
26 /**
27 * Tests whether a {@link Generator} contains an element that matches a {@link UnaryPredicate}.
28 *
29 * @version $Revision: 1156320 $ $Date: 2011-08-10 21:14:50 +0200 (Wed, 10 Aug 2011) $
30 */
31 public final class GeneratorContains<T> implements BinaryPredicate<Generator<? extends T>, UnaryPredicate<? super T>>,
32 Serializable {
33 /**
34 * serialVersionUID declaration.
35 */
36 private static final long serialVersionUID = -1539983619621733276L;
37 private static final GeneratorContains<Object> INSTANCE = new GeneratorContains<Object>();
38
39 /**
40 * Helper procedure.
41 */
42 private static class ContainsProcedure<T> implements UnaryProcedure<T> {
43 private final UnaryPredicate<? super T> pred;
44 private boolean found;
45
46 /**
47 * Create a new ContainsProcedure.
48 * @pred test
49 */
50 public ContainsProcedure(UnaryPredicate<? super T> pred) {
51 this.pred = pred;
52 }
53
54 /**
55 * {@inheritDoc}
56 */
57 public void run(T obj) {
58 found |= pred.test(obj);
59 }
60 }
61
62 /**
63 * {@inheritDoc}
64 * @param left Generator
65 * @param right UnaryPredicate
66 */
67 public boolean test(Generator<? extends T> left, UnaryPredicate<? super T> right) {
68 ContainsProcedure<T> findProcedure = new ContainsProcedure<T>(right);
69 left.run(findProcedure);
70 return findProcedure.found;
71 }
72
73 /**
74 * {@inheritDoc}
75 */
76 public boolean equals(Object obj) {
77 return obj == this || obj != null && obj.getClass().equals(getClass());
78 }
79
80 /**
81 * {@inheritDoc}
82 */
83 public int hashCode() {
84 return System.identityHashCode(INSTANCE);
85 }
86
87 /**
88 * Get a static {@link GeneratorContains} instance.
89 * @return {@link GeneratorContains}
90 */
91 public static GeneratorContains<Object> instance() {
92 return INSTANCE;
93 }
94 }