001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.validator.util;
018
019import java.io.Serializable;
020
021/**
022 * Represents a collection of 64 boolean (on/off) flags.  Individual flags
023 * are represented by powers of 2.  For example,<br>
024 * Flag 1 = 1<br>
025 * Flag 2 = 2<br>
026 * Flag 3 = 4<br>
027 * Flag 4 = 8<br><br>
028 * or using shift operator to make numbering easier:<br>
029 * Flag 1 = 1 &lt;&lt; 0<br>
030 * Flag 2 = 1 &lt;&lt; 1<br>
031 * Flag 3 = 1 &lt;&lt; 2<br>
032 * Flag 4 = 1 &lt;&lt; 3<br>
033 *
034 * <p>
035 * There cannot be a flag with a value of 3 because that represents Flag 1
036 * and Flag 2 both being on/true.
037 * </p>
038 */
039public class Flags implements Serializable, Cloneable {
040
041    private static final long serialVersionUID = 8481587558770237995L;
042
043    /**
044     * Represents the current flag state.
045     */
046    private long flags;
047
048    /**
049     * Create a new Flags object.
050     */
051    public Flags() {
052    }
053
054    /**
055     * Initialize a new Flags object with the given flags.
056     *
057     * @param flags collection of boolean flags to represent.
058     */
059    public Flags(final long flags) {
060        this.flags = flags;
061    }
062
063    /**
064     * Turn off all flags.  This is a synonym for <code>turnOffAll()</code>.
065     * @since 1.1.1
066     */
067    public void clear() {
068        this.flags = 0;
069    }
070
071    /**
072     * Clone this Flags object.
073     *
074     * @return a copy of this object.
075     * @see Object#clone()
076     */
077    @Override
078    public Object clone() {
079        try {
080            return super.clone();
081        } catch (final CloneNotSupportedException e) {
082            throw new UnsupportedOperationException("Couldn't clone Flags object.", e);
083        }
084    }
085
086    /**
087     * Tests if two Flags objects are in the same state.
088     * @param obj object being tested
089     * @see Object#equals(Object)
090     *
091     * @return whether the objects are equal.
092     */
093    @Override
094    public boolean equals(final Object obj) {
095        if (this == obj) {
096            return true;
097        }
098        if (!(obj instanceof Flags)) {
099            return false;
100        }
101        final 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}