001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.activemq.util.osgi; 018 019import java.io.BufferedReader; 020import java.io.IOException; 021import java.io.InputStream; 022import java.io.InputStreamReader; 023import java.net.URL; 024import java.util.ArrayList; 025import java.util.List; 026import java.util.Properties; 027import java.util.concurrent.ConcurrentHashMap; 028import java.util.concurrent.ConcurrentMap; 029 030import org.apache.activemq.Service; 031import org.apache.activemq.store.PersistenceAdapter; 032import org.apache.activemq.transport.Transport; 033import org.apache.activemq.transport.discovery.DiscoveryAgent; 034import org.apache.activemq.util.FactoryFinder; 035import org.apache.activemq.util.FactoryFinder.ObjectFactory; 036import org.osgi.framework.Bundle; 037import org.osgi.framework.BundleActivator; 038import org.osgi.framework.BundleContext; 039import org.osgi.framework.BundleEvent; 040import org.osgi.framework.SynchronousBundleListener; 041import org.slf4j.Logger; 042import org.slf4j.LoggerFactory; 043 044/** 045 * An OSGi bundle activator for ActiveMQ which adapts the {@link org.apache.activemq.util.FactoryFinder} 046 * to the OSGi environment. 047 * 048 */ 049public class Activator implements BundleActivator, SynchronousBundleListener, ObjectFactory { 050 051 private static final Logger LOG = LoggerFactory.getLogger(Activator.class); 052 053 private final ConcurrentMap<String, Class> serviceCache = new ConcurrentHashMap<String, Class>(); 054 private final ConcurrentMap<Long, BundleWrapper> bundleWrappers = new ConcurrentHashMap<Long, BundleWrapper>(); 055 private BundleContext bundleContext; 056 057 // ================================================================ 058 // BundleActivator interface impl 059 // ================================================================ 060 061 @Override 062 public synchronized void start(BundleContext bundleContext) throws Exception { 063 064 // This is how we replace the default FactoryFinder strategy 065 // with one that is more compatible in an OSGi env. 066 FactoryFinder.setObjectFactory(this); 067 068 debug("activating"); 069 this.bundleContext = bundleContext; 070 debug("checking existing bundles"); 071 bundleContext.addBundleListener(this); 072 for (Bundle bundle : bundleContext.getBundles()) { 073 if (bundle.getState() == Bundle.RESOLVED || bundle.getState() == Bundle.STARTING || 074 bundle.getState() == Bundle.ACTIVE || bundle.getState() == Bundle.STOPPING) { 075 register(bundle); 076 } 077 } 078 debug("activated"); 079 } 080 081 082 @Override 083 public synchronized void stop(BundleContext bundleContext) throws Exception { 084 debug("deactivating"); 085 bundleContext.removeBundleListener(this); 086 while (!bundleWrappers.isEmpty()) { 087 unregister(bundleWrappers.keySet().iterator().next()); 088 } 089 debug("deactivated"); 090 this.bundleContext = null; 091 } 092 093 // ================================================================ 094 // SynchronousBundleListener interface impl 095 // ================================================================ 096 097 @Override 098 public void bundleChanged(BundleEvent event) { 099 if (event.getType() == BundleEvent.RESOLVED) { 100 register(event.getBundle()); 101 } else if (event.getType() == BundleEvent.UNRESOLVED || event.getType() == BundleEvent.UNINSTALLED) { 102 unregister(event.getBundle().getBundleId()); 103 } 104 } 105 106 protected void register(final Bundle bundle) { 107 debug("checking bundle " + bundle.getBundleId()); 108 if( !isImportingUs(bundle) ) { 109 debug("The bundle does not import us: "+ bundle.getBundleId()); 110 return; 111 } 112 bundleWrappers.put(bundle.getBundleId(), new BundleWrapper(bundle)); 113 } 114 115 /** 116 * When bundles unload.. we remove them thier cached Class entries from the 117 * serviceCache. Future service lookups for the service will fail. 118 * 119 * TODO: consider a way to get the Broker release any references to 120 * instances of the service. 121 * 122 * @param bundleId 123 */ 124 protected void unregister(long bundleId) { 125 BundleWrapper bundle = bundleWrappers.remove(bundleId); 126 if (bundle != null) { 127 for (String path : bundle.cachedServices) { 128 debug("unregistering service for key: " +path ); 129 serviceCache.remove(path); 130 } 131 } 132 } 133 134 // ================================================================ 135 // ObjectFactory interface impl 136 // ================================================================ 137 138 @Override 139 public Object create(String path) throws IllegalAccessException, InstantiationException, IOException, ClassNotFoundException { 140 Class clazz = serviceCache.get(path); 141 if (clazz == null) { 142 StringBuffer warnings = new StringBuffer(); 143 // We need to look for a bundle that has that class. 144 int wrrningCounter=1; 145 for (BundleWrapper wrapper : bundleWrappers.values()) { 146 URL resource = wrapper.bundle.getResource(path); 147 if( resource == null ) { 148 continue; 149 } 150 151 Properties properties = loadProperties(resource); 152 153 String className = properties.getProperty("class"); 154 if (className == null) { 155 warnings.append("("+(wrrningCounter++)+") Invalid service file in bundle "+wrapper+": 'class' property not defined."); 156 continue; 157 } 158 159 try { 160 clazz = wrapper.bundle.loadClass(className); 161 } catch (ClassNotFoundException e) { 162 warnings.append("("+(wrrningCounter++)+") Bundle "+wrapper+" could not load "+className+": "+e); 163 continue; 164 } 165 166 // Yay.. the class was found. Now cache it. 167 serviceCache.put(path, clazz); 168 wrapper.cachedServices.add(path); 169 break; 170 } 171 172 if( clazz == null ) { 173 // Since OSGi is such a tricky environment to work in.. lets give folks the 174 // most information we can in the error message. 175 String msg = "Service not found: '" + path + "'"; 176 if (warnings.length()!= 0) { 177 msg += ", "+warnings; 178 } 179 throw new IOException(msg); 180 } 181 } 182 return clazz.newInstance(); 183 } 184 185 // ================================================================ 186 // Internal Helper Methods 187 // ================================================================ 188 189 private void debug(Object msg) { 190 LOG.debug(msg.toString()); 191 } 192 193 private Properties loadProperties(URL resource) throws IOException { 194 InputStream in = resource.openStream(); 195 try { 196 BufferedReader br = new BufferedReader(new InputStreamReader(in, "UTF-8")); 197 Properties properties = new Properties(); 198 properties.load(in); 199 return properties; 200 } finally { 201 try { 202 in.close(); 203 } catch (Exception e) { 204 } 205 } 206 } 207 208 private boolean isImportingUs(Bundle bundle) { 209 return isImportingClass(bundle, Service.class) 210 || isImportingClass(bundle, Transport.class) 211 || isImportingClass(bundle, DiscoveryAgent.class) 212 || isImportingClass(bundle, PersistenceAdapter.class); 213 } 214 215 private boolean isImportingClass(Bundle bundle, Class clazz) { 216 try { 217 return bundle.loadClass(clazz.getName())==clazz; 218 } catch (ClassNotFoundException e) { 219 return false; 220 } 221 } 222 223 private static class BundleWrapper { 224 private final Bundle bundle; 225 private final List<String> cachedServices = new ArrayList<String>(); 226 227 public BundleWrapper(Bundle bundle) { 228 this.bundle = bundle; 229 } 230 } 231}