001// Copyright 2005 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.hivemind.internal.ser; 016 017import java.lang.ref.WeakReference; 018 019import org.apache.hivemind.ApplicationRuntimeException; 020 021/** 022 * Class used to hold a <em>global</em> instance of 023 * {@link org.apache.hivemind.internal.ser.ServiceSerializationSupport}, so that 024 * {@link org.apache.hivemind.internal.ser.ServiceToken}s may locate them. 025 * 026 * @author Howard M. Lewis Ship 027 * @since 1.1 028 */ 029public class ServiceSerializationHelper 030{ 031 private static final ThreadLocal _threadLocal = new ThreadLocal(); 032 033 /** 034 * Returns the previously stored SSS. 035 * 036 * @throws ApplicationRuntimeException 037 * if no SSS has been stored. 038 */ 039 public static ServiceSerializationSupport getServiceSerializationSupport() 040 { 041 ServiceSerializationSupport result = null; 042 043 WeakReference reference = (WeakReference) _threadLocal.get(); 044 if (reference != null) 045 result = (ServiceSerializationSupport) reference.get(); 046 047 if (result == null) 048 throw new ApplicationRuntimeException(SerMessages.noSupportSet()); 049 050 return result; 051 } 052 053 /** 054 * Stores the SSS instance for later access; if an existing SSS is already stored, then an error 055 * is logged (should be just one SSS per class loader). 056 */ 057 058 public static void setServiceSerializationSupport( 059 ServiceSerializationSupport serviceSerializationSupport) 060 { 061 WeakReference reference = new WeakReference(serviceSerializationSupport); 062 063 _threadLocal.set(reference); 064 } 065}