Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
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| 1.8;1.8 |
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; | |
18 | ||
19 | import org.apache.commons.functor.BinaryPredicate; | |
20 | import org.apache.commons.functor.Predicate; | |
21 | import org.apache.commons.functor.UnaryPredicate; | |
22 | ||
23 | /** | |
24 | * A predicate that returns <code>false</code> | |
25 | * the first <i>n</i> times it is invoked, and | |
26 | * <code>true</code> thereafter. | |
27 | * | |
28 | * @since 1.0 | |
29 | * @version $Revision: 1160413 $ $Date: 2011-08-22 22:12:28 +0200 (Mon, 22 Aug 2011) $ | |
30 | * @author Jason Horman (jason@jhorman.org) | |
31 | * @author Rodney Waldhoff | |
32 | */ | |
33 | ||
34 | public final class Offset implements Predicate, UnaryPredicate<Object>, BinaryPredicate<Object, Object> { | |
35 | // instance variables | |
36 | //--------------------------------------------------------------- | |
37 | /** | |
38 | * The number of times the predicate must return {@code false}. | |
39 | */ | |
40 | private final int min; | |
41 | /** | |
42 | * The current number of times the predicate has been invoked. | |
43 | */ | |
44 | private int current; | |
45 | ||
46 | /** | |
47 | * Create a new Offset. | |
48 | * @param count offset | |
49 | */ | |
50 | 38 | public Offset(int count) { |
51 | 38 | if (count < 0) { |
52 | 2 | throw new IllegalArgumentException("Argument must be a non-negative integer."); |
53 | } | |
54 | 36 | this.min = count; |
55 | 36 | } |
56 | ||
57 | /** | |
58 | * {@inheritDoc} | |
59 | */ | |
60 | public synchronized boolean test() { | |
61 | // stop incrementing when we've hit max, so we don't loop around | |
62 | 134 | if (current < min) { |
63 | 74 | current++; |
64 | 74 | return false; |
65 | } | |
66 | 60 | return true; |
67 | } | |
68 | ||
69 | /** | |
70 | * {@inheritDoc} | |
71 | */ | |
72 | public boolean test(Object obj) { | |
73 | 88 | return test(); |
74 | } | |
75 | ||
76 | /** | |
77 | * {@inheritDoc} | |
78 | */ | |
79 | public boolean test(Object a, Object b) { | |
80 | 8 | return test(); |
81 | } | |
82 | ||
83 | /** | |
84 | * {@inheritDoc} | |
85 | */ | |
86 | public String toString() { | |
87 | 6 | return "Offset<" + min + ">"; |
88 | } | |
89 | ||
90 | //default == equals/hashCode due to statefulness | |
91 | } |