Mega Code Archive
A long integer counter class
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/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
import java.io.Serializable;
/**
* A long integer counter class.
*
* @version <tt>$Revision: 2800 $</tt>
* @author <a href="mailto:jason@planet57.com">Jason Dillon</a>
*/
public class LongCounter implements Serializable, Cloneable {
/** The serialVersionUID */
private static final long serialVersionUID = 1615297462859270139L;
/** The current count */
private long count;
/**
* Construct a LongCounter with a starting value.
*
* @param count
* Starting value for counter.
*/
public LongCounter(final long count) {
this.count = count;
}
/**
* Construct a LongCounter.
*/
public LongCounter() {
}
/**
* Increment the counter. (Optional operation)
*
* @return The incremented value of the counter.
*/
public long increment() {
return ++count;
}
/**
* Decrement the counter. (Optional operation)
*
* @return The decremented value of the counter.
*/
public long decrement() {
return --count;
}
/**
* Return the current value of the counter.
*
* @return The current value of the counter.
*/
public long getCount() {
return count;
}
/**
* Reset the counter to zero. (Optional operation)
*/
public void reset() {
this.count = 0;
}
/**
* Check if the given object is equal to this.
*
* @param obj
* Object to test equality with.
* @return True if object is equal to this.
*/
public boolean equals(final Object obj) {
if (obj == this)
return true;
if (obj != null && obj.getClass() == getClass()) {
return ((LongCounter) obj).count == count;
}
return false;
}
/**
* Return a string representation of this.
*
* @return A string representation of this.
*/
public String toString() {
return String.valueOf(count);
}
/**
* Return a cloned copy of this object.
*
* @return A cloned copy of this object.
*/
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
throw new InternalError();
}
}
// ///////////////////////////////////////////////////////////////////////
// Wrappers //
// ///////////////////////////////////////////////////////////////////////
/**
* Base wrapper class for other wrappers.
*/
private static class Wrapper extends LongCounter {
/** The serialVersionUID */
private static final long serialVersionUID = 6720507617603163762L;
/** The wrapped counter */
protected final LongCounter counter;
public Wrapper(final LongCounter counter) {
this.counter = counter;
}
public long increment() {
return counter.increment();
}
public long decrement() {
return counter.decrement();
}
public long getCount() {
return counter.getCount();
}
public void reset() {
counter.reset();
}
public boolean equals(final Object obj) {
return counter.equals(obj);
}
public String toString() {
return counter.toString();
}
public Object clone() {
return counter.clone();
}
}
/**
* Return a synchronized counter.
*
* @param counter
* LongCounter to synchronize.
* @return Synchronized counter.
*/
public static LongCounter makeSynchronized(final LongCounter counter) {
return new Wrapper(counter) {
/** The serialVersionUID */
private static final long serialVersionUID = 8903330696503363758L;
public synchronized long increment() {
return this.counter.increment();
}
public synchronized long decrement() {
return this.counter.decrement();
}
public synchronized long getCount() {
return this.counter.getCount();
}
public synchronized void reset() {
this.counter.reset();
}
public synchronized int hashCode() {
return this.counter.hashCode();
}
public synchronized boolean equals(final Object obj) {
return this.counter.equals(obj);
}
public synchronized String toString() {
return this.counter.toString();
}
public synchronized Object clone() {
return this.counter.clone();
}
};
}
/**
* Returns a directional counter.
*
* @param counter
* LongCounter to make directional.
* @param increasing
* True to create an increasing only or false to create a decreasing
* only.
* @return A directional counter.
*/
public static LongCounter makeDirectional(final LongCounter counter, final boolean increasing) {
LongCounter temp;
if (increasing) {
temp = new Wrapper(counter) {
/** The serialVersionUID */
private static final long serialVersionUID = -8902748795144754375L;
public long decrement() {
throw new UnsupportedOperationException();
}
public void reset() {
throw new UnsupportedOperationException();
}
};
} else {
temp = new Wrapper(counter) {
/** The serialVersionUID */
private static final long serialVersionUID = 2584758778978644599L;
public long increment() {
throw new UnsupportedOperationException();
}
};
}
return temp;
}
}
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