/*
* 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.geode.management.internal.beans;
import java.util.concurrent.atomic.AtomicLong;
/**
* Class to give a consistent sequence number to notifications
*
*
*/
public class SequenceNumber {
/** Sequence number for resource related notifications **/
private static AtomicLong sequenceNumber = new AtomicLong(1);
public static long next() {
long retVal = sequenceNumber.incrementAndGet();
if (retVal == Long.MAX_VALUE || retVal < 0) {// retVal <0 is checked for cases where other
// threads might have incremented sequenceNumber
// beyond Long.MAX_VALUE
synchronized (SequenceNumber.class) {
long currentValue = sequenceNumber.get();
if (currentValue == Long.MAX_VALUE || retVal < 0) {
sequenceNumber.set(1);
retVal = sequenceNumber.get();
} else {
retVal = currentValue;
}
}
}
return retVal;
}
}