/*
* 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.
*/
package org.apache.synapse.commons.throttle.core;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.io.Serializable;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Controls the concurrent access through throttle to the system based on policy
*/
public class ConcurrentAccessController implements Serializable {
private static Log log = LogFactory.getLog(ConcurrentAccessController.class.getName());
/* The Max number of concurrent access */
private int limit;
/* The counter variable - hold current access count */
private AtomicInteger counter;
private static final long serialVersionUID = -6857325377726757251L;
public ConcurrentAccessController(int limit) {
this.limit = limit;
this.counter = new AtomicInteger(limit);
}
/**
* Decrements by one the current value and Returns the previous value
*
* @return the previous value
*/
public int getAndDecrement() {
int ret = this.counter.getAndDecrement();
if (ret <= 0) {
this.counter.incrementAndGet();
return 0;
} else {
return ret;
}
}
/**
* Increments by one the current value and Returns the the updated value
*
* @return the updated value
*/
public int incrementAndGet() {
int ret = this.counter.incrementAndGet();
if (ret < 0) {
return 0;
}
return ret;
}
/**
* Gets the Max number of access - access limit
*
* @return the limit
*/
public int getLimit() {
return this.limit;
}
/**
* Resets the counter and the limit
*
* @param newValue The new Value
*/
public void set(int newValue) {
this.counter.set(newValue);
this.limit = newValue;
}
}