Java tutorial
/* * Copyright 2001-2004 The Apache Software Foundation. * * Licensed 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.axis.deployment.wsdd; import org.apache.axis.EngineConfiguration; import org.apache.axis.Handler; import org.apache.axis.components.logger.LogFactory; import org.apache.axis.deployment.wsdd.providers.WSDDBsfProvider; import org.apache.axis.deployment.wsdd.providers.WSDDComProvider; import org.apache.axis.deployment.wsdd.providers.WSDDHandlerProvider; import org.apache.axis.deployment.wsdd.providers.WSDDJavaCORBAProvider; import org.apache.axis.deployment.wsdd.providers.WSDDJavaEJBProvider; import org.apache.axis.deployment.wsdd.providers.WSDDJavaMsgProvider; import org.apache.axis.deployment.wsdd.providers.WSDDJavaRMIProvider; import org.apache.axis.deployment.wsdd.providers.WSDDJavaRPCProvider; import org.apache.axis.utils.JavaUtils; import org.apache.axis.utils.Messages; import org.apache.commons.discovery.ResourceNameIterator; import org.apache.commons.discovery.resource.ClassLoaders; import org.apache.commons.discovery.resource.names.DiscoverServiceNames; import org.apache.commons.logging.Log; import javax.xml.namespace.QName; import java.util.Hashtable; /** * WSDD provider element * * Represents the liason to the application being exposed * as a Web Service. * * Specific provider extension classes must be registered * by namespace URI. * * @author James Snell * @author Vishy Kasar */ public abstract class WSDDProvider { protected static Log log = LogFactory.getLog(WSDDProvider.class.getName()); // ** STATIC PROVIDER REGISTRY ** // private static final String PLUGABLE_PROVIDER_FILENAME = "org.apache.axis.deployment.wsdd.Provider"; /** XXX */ private static Hashtable providers = new Hashtable(); static { providers.put(WSDDConstants.QNAME_JAVARPC_PROVIDER, new WSDDJavaRPCProvider()); providers.put(WSDDConstants.QNAME_JAVAMSG_PROVIDER, new WSDDJavaMsgProvider()); providers.put(WSDDConstants.QNAME_HANDLER_PROVIDER, new WSDDHandlerProvider()); providers.put(WSDDConstants.QNAME_EJB_PROVIDER, new WSDDJavaEJBProvider()); providers.put(WSDDConstants.QNAME_COM_PROVIDER, new WSDDComProvider()); providers.put(WSDDConstants.QNAME_BSF_PROVIDER, new WSDDBsfProvider()); providers.put(WSDDConstants.QNAME_CORBA_PROVIDER, new WSDDJavaCORBAProvider()); providers.put(WSDDConstants.QNAME_RMI_PROVIDER, new WSDDJavaRMIProvider()); try { loadPluggableProviders(); } catch (Throwable t) { String msg = t + JavaUtils.LS + JavaUtils.stackToString(t); log.info(Messages.getMessage("exception01", msg)); } } /** Look for file META-INF/services/org.apache.axis.deployment.wsdd.Provider in all the JARS, get the classes listed in those files and add them to providers list if they are valid providers. Here is how the scheme would work. A company providing a new provider will jar up their provider related classes in a JAR file. The following file containing the name of the new provider class is also made part of this JAR file. META-INF/services/org.apache.axis.deployment.wsdd.Provider By making this JAR part of the webapp, the new provider will be automatically discovered. */ private static void loadPluggableProviders() { ClassLoader clzLoader = WSDDProvider.class.getClassLoader(); ClassLoaders loaders = new ClassLoaders(); loaders.put(clzLoader); DiscoverServiceNames dsn = new DiscoverServiceNames(loaders); ResourceNameIterator iter = dsn.findResourceNames(PLUGABLE_PROVIDER_FILENAME); while (iter.hasNext()) { String className = iter.nextResourceName(); try { Object o = Class.forName(className).newInstance(); if (o instanceof WSDDProvider) { WSDDProvider provider = (WSDDProvider) o; String providerName = provider.getName(); QName q = new QName(WSDDConstants.URI_WSDD_JAVA, providerName); providers.put(q, provider); } } catch (Exception e) { String msg = e + JavaUtils.LS + JavaUtils.stackToString(e); log.info(Messages.getMessage("exception01", msg)); continue; } } } /** * * @param uri XXX * @param prov XXX */ public static void registerProvider(QName uri, WSDDProvider prov) { providers.put(uri, prov); } /** * * @return XXX */ public WSDDOperation[] getOperations() { return null; } /** * * @param name XXX * @return XXX */ public WSDDOperation getOperation(String name) { return null; } /** * * @param registry XXX * @return XXX * @throws Exception XXX */ public static Handler getInstance(QName providerType, WSDDService service, EngineConfiguration registry) throws Exception { if (providerType == null) throw new WSDDException(Messages.getMessage("nullProvider00")); WSDDProvider provider = (WSDDProvider) providers.get(providerType); if (provider == null) { throw new WSDDException(Messages.getMessage("noMatchingProvider00", providerType.toString())); } return provider.newProviderInstance(service, registry); } /** * * @param registry XXX * @return XXX * @throws Exception XXX */ public abstract Handler newProviderInstance(WSDDService service, EngineConfiguration registry) throws Exception; public abstract String getName(); }