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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.validator.util;
18  
19  import java.io.Serializable;
20  
21  /**
22   * Represents a collection of 64 boolean (on/off) flags.  Individual flags
23   * are represented by powers of 2.  For example,<br>
24   * Flag 1 = 1<br>
25   * Flag 2 = 2<br>
26   * Flag 3 = 4<br>
27   * Flag 4 = 8<br><br>
28   * or using shift operator to make numbering easier:<br>
29   * Flag 1 = 1 &lt;&lt; 0<br>
30   * Flag 2 = 1 &lt;&lt; 1<br>
31   * Flag 3 = 1 &lt;&lt; 2<br>
32   * Flag 4 = 1 &lt;&lt; 3<br>
33   *
34   * <p>
35   * There cannot be a flag with a value of 3 because that represents Flag 1
36   * and Flag 2 both being on/true.
37   * </p>
38   */
39  public class Flags implements Serializable, Cloneable {
40  
41      private static final long serialVersionUID = 8481587558770237995L;
42  
43      /**
44       * Represents the current flag state.
45       */
46      private long flags;
47  
48      /**
49       * Create a new Flags object.
50       */
51      public Flags() {
52      }
53  
54      /**
55       * Initialize a new Flags object with the given flags.
56       *
57       * @param flags collection of boolean flags to represent.
58       */
59      public Flags(final long flags) {
60          this.flags = flags;
61      }
62  
63      /**
64       * Turn off all flags.  This is a synonym for <code>turnOffAll()</code>.
65       * @since 1.1.1
66       */
67      public void clear() {
68          this.flags = 0;
69      }
70  
71      /**
72       * Clone this Flags object.
73       *
74       * @return a copy of this object.
75       * @see Object#clone()
76       */
77      @Override
78      public Object clone() {
79          try {
80              return super.clone();
81          } catch (final CloneNotSupportedException e) {
82              throw new UnsupportedOperationException("Couldn't clone Flags object.", e);
83          }
84      }
85  
86      /**
87       * Tests if two Flags objects are in the same state.
88       * @param obj object being tested
89       * @see Object#equals(Object)
90       *
91       * @return whether the objects are equal.
92       */
93      @Override
94      public boolean equals(final Object obj) {
95          if (this == obj) {
96              return true;
97          }
98          if (!(obj instanceof Flags)) {
99              return false;
100         }
101         Flags other = (Flags) obj;
102         return flags == other.flags;
103     }
104 
105     /**
106      * Returns the current flags.
107      *
108      * @return collection of boolean flags represented.
109      */
110     public long getFlags() {
111         return this.flags;
112     }
113 
114     /**
115      * The hash code is based on the current state of the flags.
116      * @see Object#hashCode()
117      *
118      * @return the hash code for this object.
119      */
120     @Override
121     public int hashCode() {
122         return (int) this.flags;
123     }
124 
125     /**
126      * Tests whether the given flag is off.  If the flag is not a power of 2
127      * (ie. 3) this tests whether the combination of flags is off.
128      *
129      * @param flag Flag value to check.
130      *
131      * @return whether the specified flag value is off.
132      */
133     public boolean isOff(final long flag) {
134         return (this.flags & flag) == 0;
135     }
136 
137     /**
138      * Tests whether the given flag is on.  If the flag is not a power of 2
139      * (ie. 3) this tests whether the combination of flags is on.
140      *
141      * @param flag Flag value to check.
142      *
143      * @return whether the specified flag value is on.
144      */
145     public boolean isOn(final long flag) {
146         return (this.flags & flag) == flag;
147     }
148 
149     /**
150      * Returns a 64 length String with the first flag on the right and the
151      * 64th flag on the left.  A 1 indicates the flag is on, a 0 means it's
152      * off.
153      *
154      * @return string representation of this object.
155      */
156     @Override
157     public String toString() {
158         final StringBuilder bin = new StringBuilder(Long.toBinaryString(this.flags));
159         for (int i = 64 - bin.length(); i > 0; i--) { // CHECKSTYLE IGNORE MagicNumber
160             bin.insert(0, "0");
161         }
162         return bin.toString();
163     }
164 
165     /**
166      * Turns off the given flag.  If the flag is not a power of 2 (ie. 3) this
167      * turns off multiple flags.
168      *
169      * @param flag Flag value to turn off.
170      */
171     public void turnOff(final long flag) {
172         this.flags &= ~flag;
173     }
174 
175     /**
176      * Turn off all flags.
177      */
178     public void turnOffAll() {
179         this.flags = 0;
180     }
181 
182     /**
183      * Turns on the given flag.  If the flag is not a power of 2 (ie. 3) this
184      * turns on multiple flags.
185      *
186      * @param flag Flag value to turn on.
187      */
188     public void turnOn(final long flag) {
189         this.flags |= flag;
190     }
191 
192     /**
193      * Turn on all 64 flags.
194      */
195     public void turnOnAll() {
196         this.flags = 0xFFFFFFFFFFFFFFFFL;
197     }
198 
199 }