    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        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}