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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    *      https://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()}.
65       *
66       * @since 1.1.1
67       */
68      public void clear() {
69          flags = 0;
70      }
71  
72      /**
73       * Clone this Flags object.
74       *
75       * @return a copy of this object.
76       * @see Object#clone()
77       */
78      @Override
79      public Object clone() {
80          try {
81              return super.clone();
82          } catch (final CloneNotSupportedException e) {
83              throw new UnsupportedOperationException("Couldn't clone Flags object.", e);
84          }
85      }
86  
87      /**
88       * Tests if two Flags objects are in the same state.
89       *
90       * @param obj object being tested
91       * @see Object#equals(Object)
92       * @return whether the objects are equal.
93       */
94      @Override
95      public boolean equals(final Object obj) {
96          if (this == obj) {
97              return true;
98          }
99          if (!(obj instanceof Flags)) {
100             return false;
101         }
102         final Flags other = (Flags) obj;
103         return flags == other.flags;
104     }
105 
106     /**
107      * Returns the current flags.
108      *
109      * @return collection of boolean flags represented.
110      */
111     public long getFlags() {
112         return flags;
113     }
114 
115     /**
116      * The hash code is based on the current state of the flags.
117      *
118      * @see Object#hashCode()
119      * @return the hash code for this object.
120      */
121     @Override
122     public int hashCode() {
123         return (int) flags;
124     }
125 
126     /**
127      * Tests whether the given flag is off. If the flag is not a power of 2
128      * (for example, 3) this tests whether the combination of flags is off.
129      *
130      * @param flag Flag value to check.
131      * @return whether the specified flag value is off.
132      */
133     public boolean isOff(final long flag) {
134         return (flags & flag) == 0;
135     }
136 
137     /**
138      * Tests whether the given flag is on. If the flag is not a power of 2
139      * (for example, 3) this tests whether the combination of flags is on.
140      *
141      * @param flag Flag value to check.
142      * @return whether the specified flag value is on.
143      */
144     public boolean isOn(final long flag) {
145         return (flags & flag) == flag;
146     }
147 
148     /**
149      * Returns a 64 length String with the first flag on the right and the
150      * 64th flag on the left. A 1 indicates the flag is on, a 0 means it's
151      * off.
152      *
153      * @return string representation of this object.
154      */
155     @Override
156     public String toString() {
157         final StringBuilder bin = new StringBuilder(Long.toBinaryString(flags));
158         for (int i = 64 - bin.length(); i > 0; i--) { // CHECKSTYLE IGNORE MagicNumber
159             bin.insert(0, "0");
160         }
161         return bin.toString();
162     }
163 
164     /**
165      * Turns off the given flag. If the flag is not a power of 2 (for example, 3) this
166      * turns off multiple flags.
167      *
168      * @param flag Flag value to turn off.
169      */
170     public void turnOff(final long flag) {
171         flags &= ~flag;
172     }
173 
174     /**
175      * Turn off all flags.
176      */
177     public void turnOffAll() {
178         flags = 0;
179     }
180 
181     /**
182      * Turns on the given flag. If the flag is not a power of 2 (for example, 3) this
183      * turns on multiple flags.
184      *
185      * @param flag Flag value to turn on.
186      */
187     public void turnOn(final long flag) {
188         flags |= flag;
189     }
190 
191     /**
192      * Turn on all 64 flags.
193      */
194     public void turnOnAll() {
195         flags = 0xFFFFFFFFFFFFFFFFL;
196     }
197 
198 }