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.generator;
18
19 import org.apache.commons.functor.UnaryPredicate;
20 import org.apache.commons.functor.UnaryProcedure;
21
22 /**
23 * Wrap another {@link Generator} such that {@link #run(UnaryProcedure)} continues
24 * as long as a condition is true (test before).
25 *
26 * @version $Revision: 1156802 $ $Date: 2011-08-11 22:13:34 +0200 (Thu, 11 Aug 2011) $
27 */
28 public class WhileGenerate<E> extends BaseGenerator<E> {
29 private final UnaryPredicate<? super E> test;
30
31 /**
32 * Create a new WhileGenerate.
33 * @param test {@link UnaryPredicate}
34 * @param wrapped {@link Generator}
35 */
36 public WhileGenerate(UnaryPredicate<? super E> test, Generator<? extends E> wrapped) {
37 super(wrapped);
38 if (wrapped == null) {
39 throw new IllegalArgumentException("Generator argument was null");
40 }
41 if (test == null) {
42 throw new IllegalArgumentException("UnaryPredicate argument was null");
43 }
44 this.test = test;
45 }
46
47 /**
48 * {@inheritDoc}
49 */
50 public void run(final UnaryProcedure<? super E> proc) {
51 getWrappedGenerator().run(new UnaryProcedure<E>() {
52 public void run(E obj) {
53 if (!test.test(obj)) {
54 getWrappedGenerator().stop();
55 } else {
56 proc.run(obj);
57 }
58 }
59 });
60 }
61
62 /**
63 * {@inheritDoc}
64 */
65 @SuppressWarnings("unchecked")
66 @Override
67 protected Generator<? extends E> getWrappedGenerator() {
68 return (Generator<? extends E>) super.getWrappedGenerator();
69 }
70
71 /**
72 * {@inheritDoc}
73 */
74 public boolean equals(Object obj) {
75 if (obj == this) {
76 return true;
77 }
78 if (!(obj instanceof WhileGenerate<?>)) {
79 return false;
80 }
81 WhileGenerate<?> other = (WhileGenerate<?>) obj;
82 return other.getWrappedGenerator().equals(getWrappedGenerator()) && other.test.equals(test);
83 }
84
85 /**
86 * {@inheritDoc}
87 */
88 public int hashCode() {
89 int result = "WhileGenerate".hashCode();
90 result <<= 2;
91 Generator<?> gen = getWrappedGenerator();
92 result ^= gen == null ? 0 : gen.hashCode();
93 result <<= 2;
94 result ^= test == null ? 0 : test.hashCode();
95 return result;
96 }
97 }