/*
* 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.internal.tcp;
import org.apache.geode.internal.UniqueIdGenerator;
/**
* MsgId is used to generate unique ids to attach to messages. To get a new id call obtain. When you
* are done with the id call release. Failure to call release will eventually cause obtain to fail
* with an exception.
* <p>
* Currently ids are in the range 0..32767 inclusive.
*
* @since GemFire 5.0.2
*
*/
public class MsgIdGenerator {
/**
* A value that can be used to indicate that a message does not have an id.
*/
public static final short NO_MSG_ID = -1;
private static final short MAX_ID = 32767;
private static final UniqueIdGenerator uigen = new UniqueIdGenerator(MAX_ID);
private MsgIdGenerator() {
// static only; no constructor
}
/**
* Obtains a message id. Callers of this must call release when finished with the id.
*
* @throws IllegalStateException if all ids have been obtained
*/
public static short obtain() {
return (short) uigen.obtain();
}
public static void release(short id) {
if (id != NO_MSG_ID) {
uigen.release(id);
}
}
}