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.Predicate;
20 import org.apache.commons.functor.Procedure;
21 import org.apache.commons.functor.core.composite.ConditionalProcedure;
22 import org.apache.commons.lang3.Validate;
23
24 /**
25 * Generator that filters another Generator by only passing through those elements
26 * that are matched by a specified Predicate.
27 *
28 * @param <E> the type of elements held in this generator.
29 * @version $Revision: 1522355 $ $Date: 2013-09-12 06:29:46 +0200 (Do, 12 Sep 2013) $
30 */
31 public class FilteredGenerator<E> extends BaseGenerator<E> {
32
33 /**
34 * A generator can wrap another generator.
35 * */
36 private Generator<? extends E> wrappedGenerator;
37
38 /**
39 * The predicate used to filter.
40 */
41 private final Predicate<? super E> pred;
42
43 /**
44 * Create a new FilteredGenerator.
45 * @param wrapped Generator to wrap
46 * @param pred filtering Predicate
47 */
48 public FilteredGenerator(Generator<? extends E> wrapped, Predicate<? super E> pred) {
49 this.wrappedGenerator = Validate.notNull(wrapped, "Generator argument was null");
50 this.pred = Validate.notNull(pred, "Predicate argument was null");
51 }
52
53 /**
54 * {@inheritDoc}
55 */
56 public void run(Procedure<? super E> proc) {
57 getWrappedGenerator().run(new ConditionalProcedure<E>(pred, proc));
58 }
59
60 /**
61 * Get the generator that is being wrapped.
62 * @return Generator
63 */
64 protected Generator<? extends E> getWrappedGenerator() {
65 return this.wrappedGenerator;
66 }
67
68 /**
69 * {@inheritDoc}
70 */
71 @Override
72 public boolean equals(Object obj) {
73 if (obj == this) {
74 return true;
75 }
76 if (!(obj instanceof FilteredGenerator<?>)) {
77 return false;
78 }
79 FilteredGenerator<?> other = (FilteredGenerator<?>) obj;
80 return other.getWrappedGenerator().equals(getWrappedGenerator()) && other.pred.equals(pred);
81 }
82
83 /**
84 * {@inheritDoc}
85 */
86 @Override
87 public int hashCode() {
88 int result = "FilteredGenerator".hashCode();
89 result <<= 2;
90 Generator<?> gen = getWrappedGenerator();
91 result ^= gen.hashCode();
92 result <<= 2;
93 result ^= pred.hashCode();
94 return result;
95 }
96 }