Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
Limit |
|
| 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>true</code> | |
25 | * the first <i>n</i> times it is invoked. | |
26 | * | |
27 | * @since 1.0 | |
28 | * @version $Revision: 1160412 $ $Date: 2011-08-22 22:10:41 +0200 (Mon, 22 Aug 2011) $ | |
29 | * @author Jason Horman (jason@jhorman.org) | |
30 | * @author Rodney Waldhoff | |
31 | */ | |
32 | ||
33 | public final class Limit implements Predicate, UnaryPredicate<Object>, BinaryPredicate<Object, Object> { | |
34 | // instance variables | |
35 | //--------------------------------------------------------------- | |
36 | /** | |
37 | * The max number of times the predicate can be invoked. | |
38 | */ | |
39 | private final int max; | |
40 | /** | |
41 | * The current number of times the predicate has been invoked. | |
42 | */ | |
43 | private int current; | |
44 | ||
45 | /** | |
46 | * Create a new Limit. | |
47 | * @param count limit | |
48 | */ | |
49 | 34 | public Limit(int count) { |
50 | 34 | if (count < 0) { |
51 | 2 | throw new IllegalArgumentException("Argument must be a non-negative integer."); |
52 | } | |
53 | 32 | this.max = count; |
54 | 32 | } |
55 | ||
56 | /** | |
57 | * {@inheritDoc} | |
58 | */ | |
59 | public synchronized boolean test() { | |
60 | // stop incrementing when we've hit max, so we don't loop around | |
61 | 70 | if (current < max) { |
62 | 42 | current++; |
63 | 42 | return true; |
64 | } | |
65 | 28 | return false; |
66 | } | |
67 | ||
68 | /** | |
69 | * {@inheritDoc} | |
70 | */ | |
71 | public boolean test(Object obj) { | |
72 | 24 | return test(); |
73 | } | |
74 | ||
75 | /** | |
76 | * {@inheritDoc} | |
77 | */ | |
78 | public boolean test(Object a, Object b) { | |
79 | 8 | return test(); |
80 | } | |
81 | ||
82 | /** | |
83 | * {@inheritDoc} | |
84 | */ | |
85 | public String toString() { | |
86 | 6 | return "Limit<" + max + ">"; |
87 | } | |
88 | ||
89 | //default == equals/hashCode due to statefulness | |
90 | } |