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. 014 015 package org.apache.hivemind.internal.ser; 016 017 import java.lang.ref.WeakReference; 018 019 import org.apache.commons.logging.Log; 020 import org.apache.commons.logging.LogFactory; 021 import org.apache.hivemind.ApplicationRuntimeException; 022 023 /** 024 * Class used to hold a <em>global</em> instance of 025 * {@link org.apache.hivemind.internal.ser.ServiceSerializationSupport}, so that 026 * {@link org.apache.hivemind.internal.ser.ServiceToken}s may locate them. 027 * 028 * @author Howard M. Lewis Ship 029 * @since 1.1 030 */ 031 public class ServiceSerializationHelper 032 { 033 private static final Log LOG = LogFactory.getLog(ServiceSerializationHelper.class); 034 035 private static final ThreadLocal _threadLocal = new ThreadLocal(); 036 037 /** 038 * Returns the previously stored SSS. 039 * 040 * @throws ApplicationRuntimeException 041 * if no SSS has been stored. 042 */ 043 public static ServiceSerializationSupport getServiceSerializationSupport() 044 { 045 ServiceSerializationSupport result = null; 046 047 WeakReference reference = (WeakReference) _threadLocal.get(); 048 if (reference != null) 049 result = (ServiceSerializationSupport) reference.get(); 050 051 if (result == null) 052 throw new ApplicationRuntimeException(SerMessages.noSupportSet()); 053 054 return result; 055 } 056 057 /** 058 * Stores the SSS instance for later access; if an existing SSS is already stored, then an error 059 * is logged (should be just one SSS per class loader). 060 */ 061 062 public static void setServiceSerializationSupport( 063 ServiceSerializationSupport serviceSerializationSupport) 064 { 065 WeakReference reference = new WeakReference(serviceSerializationSupport); 066 067 _threadLocal.set(reference); 068 } 069 }