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Java > Open Source Codes > org > apache > commons > validator > util > Flags


1 /*
2  * $Id: Flags.java 155434 2005-02-26 13:16:41Z dirkv $
3  * $Rev$
4  * $Date: 2005-02-26 05:16:41 -0800 (Sat, 26 Feb 2005) $
5  *
6  * ====================================================================
7  * Copyright 2003-2005 The Apache Software Foundation
8  *
9  * Licensed under the Apache License, Version 2.0 (the "License");
10  * you may not use this file except in compliance with the License.
11  * You may obtain a copy of the License at
12  *
13  * http://www.apache.org/licenses/LICENSE-2.0
14  *
15  * Unless required by applicable law or agreed to in writing, software
16  * distributed under the License is distributed on an "AS IS" BASIS,
17  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18  * See the License for the specific language governing permissions and
19  * limitations under the License.
20  */
21
22 package org.apache.commons.validator.util;
23
24 import java.io.Serializable JavaDoc;
25
26 /**
27  * Represents a collection of 64 boolean (on/off) flags. Individual flags
28  * are represented by powers of 2. For example,<br/>
29  * Flag 1 = 1<br/>
30  * Flag 2 = 2<br/>
31  * Flag 3 = 4<br/>
32  * Flag 4 = 8<br/><br/>
33  * or using shift operator to make numbering easier:<br/>
34  * Flag 1 = 1 &lt;&lt; 0<br/>
35  * Flag 2 = 1 &lt;&lt; 1<br/>
36  * Flag 3 = 1 &lt;&lt; 2<br/>
37  * Flag 4 = 1 &lt;&lt; 3<br/>
38  *
39  * <p>
40  * There cannot be a flag with a value of 3 because that represents Flag 1
41  * and Flag 2 both being on/true.
42  * </p>
43  */
44 public class Flags implements Serializable JavaDoc {
45
46     /**
47      * Represents the current flag state.
48      */
49     private long flags = 0;
50
51     /**
52      * Create a new Flags object.
53      */
54     public Flags() {
55         super();
56     }
57
58     /**
59      * Initialize a new Flags object with the given flags.
60      */
61     public Flags(long flags) {
62         super();
63         this.flags = flags;
64     }
65
66     /**
67      * Returns the current flags.
68      */
69     public long getFlags() {
70         return this.flags;
71     }
72
73     /**
74      * Tests whether the given flag is on. If the flag is not a power of 2
75      * (ie. 3) this tests whether the combination of flags is on.
76      */
77     public boolean isOn(long flag) {
78         return (this.flags & flag) > 0;
79     }
80
81     /**
82      * Tests whether the given flag is off. If the flag is not a power of 2
83      * (ie. 3) this tests whether the combination of flags is off.
84      */
85     public boolean isOff(long flag) {
86         return (this.flags & flag) == 0;
87     }
88
89     /**
90      * Turns on the given flag. If the flag is not a power of 2 (ie. 3) this
91      * turns on multiple flags.
92      */
93     public void turnOn(long flag) {
94         this.flags |= flag;
95     }
96
97     /**
98      * Turns off the given flag. If the flag is not a power of 2 (ie. 3) this
99      * turns off multiple flags.
100      */
101     public void turnOff(long flag) {
102         this.flags &= ~flag;
103     }
104
105     /**
106      * Turn off all flags.
107      */
108     public void turnOffAll() {
109         this.flags = 0;
110     }
111     
112     /**
113      * Turn off all flags. This is a synonym for <code>turnOffAll()</code>.
114      * @since Validator 1.1.1
115      */
116     public void clear() {
117         this.flags = 0;
118     }
119
120     /**
121      * Turn on all 64 flags.
122      */
123     public void turnOnAll() {
124         this.flags = Long.MAX_VALUE;
125     }
126
127     /**
128      * Clone this Flags object.
129      * @see java.lang.Object#clone()
130      */
131     public Object JavaDoc clone() {
132         try {
133             return super.clone();
134         } catch(CloneNotSupportedException JavaDoc e) {
135             throw new RuntimeException JavaDoc("Couldn't clone Flags object.");
136         }
137     }
138
139     /**
140      * Tests if two Flags objects are in the same state.
141      * @param obj object being tested
142      * @see java.lang.Object#equals(java.lang.Object)
143      */
144     public boolean equals(Object JavaDoc obj) {
145         if (!(obj instanceof Flags)) {
146             return false;
147         }
148
149         if (obj == this) {
150             return true;
151         }
152
153         Flags f = (Flags) obj;
154
155         return this.flags == f.flags;
156     }
157
158     /**
159      * The hash code is based on the current state of the flags.
160      * @see java.lang.Object#hashCode()
161      */
162     public int hashCode() {
163         return (int) this.flags;
164     }
165
166     /**
167      * Returns a 64 length String with the first flag on the right and the
168      * 64th flag on the left. A 1 indicates the flag is on, a 0 means it's
169      * off.
170      */
171     public String JavaDoc toString() {
172         StringBuffer JavaDoc bin = new StringBuffer JavaDoc(Long.toBinaryString(this.flags));
173         for (int i = 64 - bin.length(); i > 0; i--) {
174             bin.insert(0, "0");
175         }
176         return bin.toString();
177     }
178
179 }
180
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