Mega Code Archive
Represents a collection of 64 boolean (onoff) flags
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.Serializable;
/**
* Represents a collection of 64 boolean (on/off) flags. Individual flags
* are represented by powers of 2. For example,<br/>
* Flag 1 = 1<br/>
* Flag 2 = 2<br/>
* Flag 3 = 4<br/>
* Flag 4 = 8<br/><br/>
* or using shift operator to make numbering easier:<br/>
* Flag 1 = 1 << 0<br/>
* Flag 2 = 1 << 1<br/>
* Flag 3 = 1 << 2<br/>
* Flag 4 = 1 << 3<br/>
*
* <p>
* There cannot be a flag with a value of 3 because that represents Flag 1
* and Flag 2 both being on/true.
* </p>
*
* @version $Revision: 478334 $ $Date: 2006-11-22 21:31:54 +0000 (Wed, 22 Nov 2006) $
*/
public class Flags implements Serializable {
/**
* Represents the current flag state.
*/
private long flags = 0;
/**
* Create a new Flags object.
*/
public Flags() {
super();
}
/**
* Initialize a new Flags object with the given flags.
*
* @param flags collection of boolean flags to represent.
*/
public Flags(long flags) {
super();
this.flags = flags;
}
/**
* Returns the current flags.
*
* @return collection of boolean flags represented.
*/
public long getFlags() {
return this.flags;
}
/**
* Tests whether the given flag is on. If the flag is not a power of 2
* (ie. 3) this tests whether the combination of flags is on.
*
* @param flag Flag value to check.
*
* @return whether the specified flag value is on.
*/
public boolean isOn(long flag) {
return (this.flags & flag) > 0;
}
/**
* Tests whether the given flag is off. If the flag is not a power of 2
* (ie. 3) this tests whether the combination of flags is off.
*
* @param flag Flag value to check.
*
* @return whether the specified flag value is off.
*/
public boolean isOff(long flag) {
return (this.flags & flag) == 0;
}
/**
* Turns on the given flag. If the flag is not a power of 2 (ie. 3) this
* turns on multiple flags.
*
* @param flag Flag value to turn on.
*/
public void turnOn(long flag) {
this.flags |= flag;
}
/**
* Turns off the given flag. If the flag is not a power of 2 (ie. 3) this
* turns off multiple flags.
*
* @param flag Flag value to turn off.
*/
public void turnOff(long flag) {
this.flags &= ~flag;
}
/**
* Turn off all flags.
*/
public void turnOffAll() {
this.flags = 0;
}
/**
* Turn off all flags. This is a synonym for <code>turnOffAll()</code>.
* @since Validator 1.1.1
*/
public void clear() {
this.flags = 0;
}
/**
* Turn on all 64 flags.
*/
public void turnOnAll() {
this.flags = Long.MAX_VALUE;
}
/**
* Clone this Flags object.
*
* @return a copy of this object.
* @see java.lang.Object#clone()
*/
public Object clone() {
try {
return super.clone();
} catch(CloneNotSupportedException e) {
throw new RuntimeException("Couldn't clone Flags object.");
}
}
/**
* Tests if two Flags objects are in the same state.
* @param obj object being tested
* @see java.lang.Object#equals(java.lang.Object)
*
* @return whether the objects are equal.
*/
public boolean equals(Object obj) {
if (!(obj instanceof Flags)) {
return false;
}
if (obj == this) {
return true;
}
Flags f = (Flags) obj;
return this.flags == f.flags;
}
/**
* The hash code is based on the current state of the flags.
* @see java.lang.Object#hashCode()
*
* @return the hash code for this object.
*/
public int hashCode() {
return (int) this.flags;
}
/**
* Returns a 64 length String with the first flag on the right and the
* 64th flag on the left. A 1 indicates the flag is on, a 0 means it's
* off.
*
* @return string representation of this object.
*/
public String toString() {
StringBuffer bin = new StringBuffer(Long.toBinaryString(this.flags));
for (int i = 64 - bin.length(); i > 0; i--) {
bin.insert(0, "0");
}
return bin.toString();
}
}
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