/**
* This file is part of Waarp Project.
*
* Copyright 2009, Frederic Bregier, and individual contributors by the @author tags. See the
* COPYRIGHT.txt in the distribution for a full listing of individual contributors.
*
* All Waarp Project is free software: you can redistribute it and/or modify it under the terms of
* the GNU General Public License as published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* Waarp 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 General
* Public License for more details.
*
* You should have received a copy of the GNU General Public License along with Waarp . If not, see
* <http://www.gnu.org/licenses/>.
*/
package org.waarp.ftp.simpleimpl.config;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Circular Value used by passive connections to find the next valid port to propose to the client.
*
* @author Frederic Bregier
*
*/
class CircularIntValue {
/**
* Min value
*/
private final int min;
/**
* Max value
*/
private final int max;
/**
* Current Value
*/
private AtomicInteger current;
/**
* Create a circular range of values
*
* @param min
* @param max
*/
public CircularIntValue(int min, int max) {
this.min = min;
this.max = max;
current = new AtomicInteger(this.min - 1);
}
/**
* Get the next value
*
* @return the next value
*/
public int getNext() {
synchronized (current) {
if (!current.compareAndSet(max, min)) {
current.incrementAndGet();
}
return current.get();
}
}
}