| /* |
| * 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.annotations.internal.MakeNotStatic; |
| 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; |
| @MakeNotStatic("Possibly safe singleton to share?") |
| 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); |
| } |
| } |
| } |