Java tutorial
/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 2006-2018 Oracle and/or its affiliates. All rights reserved. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common Development * and Distribution License("CDDL") (collectively, the "License"). You * may not use this file except in compliance with the License. You can * obtain a copy of the License at * https://oss.oracle.com/licenses/CDDL+GPL-1.1 * or LICENSE.txt. 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If you don't indicate a single choice of license, a * recipient has the option to distribute your version of this file under * either the CDDL, the GPL Version 2 or to extend the choice of license to * its licensees as provided above. However, if you add GPL Version 2 code * and therefore, elected the GPL Version 2 license, then the option applies * only if the new code is made subject to such option by the copyright * holder. */ package javax.ejb.embeddable; import java.io.PrintWriter; import java.io.StringWriter; import java.util.Map; import java.util.HashMap; import java.util.Set; import java.util.HashSet; import java.util.ServiceLoader; import javax.naming.Context; import javax.ejb.EJBException; import javax.ejb.spi.EJBContainerProvider; /** * Used to execute an EJB application in an embeddable container. * * @since EJB 3.1 */ public abstract class EJBContainer implements AutoCloseable { /** * Standard property name for specifying the embeddable container implementation bootstrap * class. Property value is a fully-qualified class name. */ public static final String PROVIDER = "javax.ejb.embeddable.provider"; /** * Standard property name for specifying the set of modules to be * initialized. Property value is one of the following : * <ul> * <li> a single module name String from the JVM classpath * <li> a String[] array of module names from the JVM classpath * <li> a java.io.File representing an ejb-jar or exploded ejb-jar directory * <li> a java.io.File array, each element of which represents an ejb-jar * or exploded ejb-jar directory * </ul> */ public static final String MODULES = "javax.ejb.embeddable.modules"; /** * Standard property name for specifying the application name of * the EJB modules executing within the embeddable container. If * specified, the property value applies to the * <code><app-name></code> portion of the portable * global JNDI name syntax. If this property is not specified, the * <code><app-name></code> portion of the portable * global JNDI name syntax does not apply. */ public static final String APP_NAME = "javax.ejb.embeddable.appName"; /** * Create and initialize an embeddable EJB container. JVM classpath is * searched for all ejb-jars or exploded ejb-jars in directory format. * * @return EJBContainer instance * * @exception javax.ejb.EJBException Thrown if the container or application * could not be successfully initialized. */ public static EJBContainer createEJBContainer() { return createEJBContainer(null); } /** * Create and initialize an embeddable EJB container with a * set of configuration properties. * * @param properties Spec-defined and/or vendor-specific * properties. The spec reserves the prefix * <code>"javax.ejb."</code> for spec-defined properties. * * @return EJBContainer instance * * @exception javax.ejb.EJBException Thrown if the container or application * could not be successfully initialized. */ public static EJBContainer createEJBContainer(Map<?, ?> properties) { EJBContainer container = null; Map<String, String> errors = new HashMap<String, String>(); Set<String> returnedNull = new HashSet<String>(); providers.reload(); for (EJBContainerProvider provider : providers) { try { container = provider.createEJBContainer(properties); if (container != null) { break; } else { returnedNull.add(provider.getClass().getName()); } } catch (EJBException e) { // The provider is eligible but encountered problems throw e; } catch (Throwable t) { // ignore but remember the message in case all fail: // according to Spec the provider must return null from // createEJBContainer(), if not the right provider. // But non-compliant provider may throw exception errors.put(provider.getClass().getName(), createErrorMessage(t)); } } if (container == null) { reportError(properties, errors, returnedNull); } return container; } /** * Retrieve a naming context for looking up references to session beans * executing in the embeddable container. * * @return naming context */ abstract public Context getContext(); /** * Shutdown an embeddable EJBContainer instance. Embeddable applications * should always call <code>close()</code> in order to free up the resources * associated with the embeddable container. */ abstract public void close(); //Private variables private static final String newLine = "\r\n"; private static final ServiceLoader<EJBContainerProvider> providers = ServiceLoader .load(EJBContainerProvider.class); /** * Create a meaningful EJBException in case no EJBContainer provider had * been found. * * @param properties the properties passed as an argument to the * createEJBContainer() method * * @param errors the Map of errors encountered during the createEJBContainer() call * * @param returnedNull the Set of providers that returned null on * createEJBContainer() call * * @throws EJBException */ private static void reportError(Map<?, ?> properties, Map<String, String> errors, Set<String> returnedNull) throws EJBException { StringBuffer message = new StringBuffer("No EJBContainer provider available"); if (properties != null) { Object specifiedProvider = properties.get(PROVIDER); if (specifiedProvider != null) { message.append(" for requested provider: " + specifiedProvider); } } if (errors.isEmpty() && returnedNull.isEmpty()) { message.append(": no provider names had been found."); } else { message.append("\n"); } for (Map.Entry me : errors.entrySet()) { message.append("Provider named "); message.append(me.getKey()); message.append(" threw unexpected exception at create EJBContainer: \n"); message.append(me.getValue()).append("\n"); } if (!returnedNull.isEmpty()) { message.append("The following providers:\n"); for (String n : returnedNull) { message.append(n).append("\n"); } message.append("Returned null from createEJBContainer call.\n"); } throw new EJBException(message.toString()); } private static String createErrorMessage(Throwable t) { StringWriter errorMessage = new StringWriter(); errorMessage.append(t.getClass().getName()).append(newLine); t.printStackTrace(new PrintWriter(errorMessage)); errorMessage.append(newLine); return errorMessage.toString(); } }