src/javax/persistence/Persistence.java - gerrit/eclipselink/javax.persistence - Git at Google

 /*
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
  *
  * Copyright 1997-2007 Sun Microsystems, Inc. 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://glassfish.dev.java.net/public/CDDL+GPL.html
  * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
  * language governing permissions and limitations under the License.
  *
  * When distributing the software, include this License Header Notice in each
  * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
  * Sun designates this particular file as subject to the "Classpath" exception
  * as provided by Sun in the GPL Version 2 section of the License file that
  * accompanied this code.  If applicable, add the following below the License
  * Header, with the fields enclosed by brackets [] replaced by your own
  * identifying information: "Portions Copyrighted [year]
  * [name of copyright owner]"
  *
  * Contributor(s):
  *
  * Mike Keith - Add ability to run in OSGi and other environments by making
  *              provider discovery a strategy. Also allow providers to be added
  *              and removed dynamically.
  *
  * Mike Keith elects to include this software in this distribution under
  * the CDDL license.
  *
  * If you wish your version of this file to be governed by only the CDDL or
  * only the GPL Version 2, indicate your decision by adding "[Contributor]
  * elects to include this software in this distribution under the [CDDL or GPL
  * Version 2] license."  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.persistence;

 // J2SE imports
 import java.io.IOException;
 import java.io.BufferedReader;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.Set;
 import java.util.Map;
 import java.util.HashSet;
 import java.util.Enumeration;
 import java.net.URL;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;

 // persistence imports
 import javax.persistence.spi.PersistenceProvider;

 /**
  * Bootstrap class that is used to obtain an {@link EntityManagerFactory}.
  *
  * @since Java Persistence 1.0
  */
 public class Persistence {

     protected static Set<PersistenceProvider> providers = new HashSet<PersistenceProvider>();

     // Used to resolve and return providers.
     protected static ProviderResolver providerResolver = new DefaultProviderResolver();

     /**
      * Get the resolver being used to obtain the available providers.
      *
      * @return The resolver used to obtain all available providers
      */
     public static ProviderResolver getProviderResolver() { return providerResolver; }

     /**
      * Set the resolver to an alternate provider resolution strategy (implemented externally).
      * This can be used to override the default resolution strategy.
      *
      * @param resolver The resolver to use when obtaining all available providers
      */
     public static void setProviderResolver(ProviderResolver resolver) { providerResolver = resolver; }

     /**
      * Create and return an EntityManagerFactory for the
      * named persistence unit.
      *
      * @param persistenceUnitName The name of the persistence unit
      * @return The factory that creates EntityManagers configured
      * according to the specified persistence unit
      */
     public static EntityManagerFactory createEntityManagerFactory(String persistenceUnitName) {
         return createEntityManagerFactory(persistenceUnitName, null);
     }

     /**
      * Create and return an EntityManagerFactory for the
      * named persistence unit using the given properties.
      *
      * @param persistenceUnitName The name of the persistence unit
      * @param properties Additional properties to use when creating the
      * factory. The values of these properties override any values
      * that may have been configured elsewhere.
      * @return The factory that creates EntityManagers configured
      * according to the specified persistence unit.
      */
     public static EntityManagerFactory createEntityManagerFactory(
             String persistenceUnitName, Map properties) {

     	EntityManagerFactory emf = null;
         if (providers.size() == 0) {
             try{
                 providers.addAll(providerResolver.findAllProviders());
             } catch (IOException exc){}
         }
         for (PersistenceProvider provider : providers) {
             emf = provider.createEntityManagerFactory(persistenceUnitName, properties);
             if (emf != null){
                 break;
             }
         }
         if (emf == null) {
             throw new PersistenceException("No Persistence provider for EntityManager named " + persistenceUnitName);
         }
         return emf;
     }

     // ====================
     // Internal API methods
     // ====================

     /**
      * Dynamically add a provider to the set of available providers.
      */
     public static void addProvider(PersistenceProvider provider) {
     	providers.add(provider);
     }

     /**
      * Dynamically remove a named provider from the set of available providers.
      */
     public static void removeProvider(String providerName) {
         for (Iterator<PersistenceProvider> i = providers.iterator(); i.hasNext(); ) {
     		if (i.next().getClass().getName().equals(providerName)) {
     			i.remove();
     		}
 		}
     }

     /**
      * Reinitialize to have no providers.
      */
     public static void resetProviders() {
     	providers = new HashSet<PersistenceProvider>();
     }

     // ==============================================================
     // Interface for overriding available provider discovery strategy
     // ==============================================================

     /**
      * Interface used by the Persistence class to obtain all available persistence providers.
      */
     public static interface ProviderResolver {
     	Collection<PersistenceProvider> findAllProviders() throws IOException;
     }

     // =============================
     // Internal implementation class
     // =============================

     /**
      * Default provider resolver class to use when none is explicitly set.
      *
      * Uses the META-INF/services approach as described in the Java Persistence
      * specification. A getResources() call is made on the current context classloader
      * to find the service provider files on the classpath. Any service files found
      * are then read to obtain the classes that implement the persistence provider
      * interface.
      */
     public static class DefaultProviderResolver implements ProviderResolver {

         public static final String PERSISTENCE_PROVIDER = "javax.persistence.spi.PersistenceProvider";
     	public static final String SERVICE_PROVIDER_FILE = "META-INF/services/" + PERSISTENCE_PROVIDER;


     	public Collection<PersistenceProvider> findAllProviders() throws IOException {

 	        ClassLoader loader = Thread.currentThread().getContextClassLoader();
 	        Enumeration<URL> resources = loader.getResources(SERVICE_PROVIDER_FILE);

 	        Set<String> providerNames = new HashSet<String>();
 	        while (resources.hasMoreElements()) {
 	            URL url = resources.nextElement();
 	            InputStream is = url.openStream();
 	            try {
 	            	providerNames.addAll(providerNamesFromReader(new BufferedReader(new InputStreamReader(is))));
 	            } finally {
 	                is.close();
 	            }
 	        }
 	        Collection<PersistenceProvider> loadedProviders = new HashSet<PersistenceProvider>();
 	        for (String s : providerNames) {
 	            try{
 	            	loadedProviders.add((PersistenceProvider)loader.loadClass(s).newInstance());
 	            } catch (ClassNotFoundException exc){
 	            } catch (InstantiationException exc){
 	            } catch (IllegalAccessException exc){
 	            }
 	        }
 	        return loadedProviders;
     	}

     	private static final Pattern nonCommentPattern = Pattern.compile("^([^#]+)");

 	    private Set<String> providerNamesFromReader(BufferedReader reader) throws IOException {
 	        Set<String> providerNames = new HashSet<String>();
 	        String line;
 	        while ((line = reader.readLine()) != null) {
 	            line = line.trim();
 	            Matcher m = nonCommentPattern.matcher(line);
 	            if (m.find()) {
 	            	providerNames.add(m.group().trim());
 	            }
 	        }
 	        return providerNames;
 	    }
     }
 }
	/*
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
	*
	* Copyright 1997-2007 Sun Microsystems, Inc. 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://glassfish.dev.java.net/public/CDDL+GPL.html
	* or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
	* language governing permissions and limitations under the License.
	*
	* When distributing the software, include this License Header Notice in each
	* file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
	* Sun designates this particular file as subject to the "Classpath" exception
	* as provided by Sun in the GPL Version 2 section of the License file that
	* accompanied this code. If applicable, add the following below the License
	* Header, with the fields enclosed by brackets [] replaced by your own
	* identifying information: "Portions Copyrighted [year]
	* [name of copyright owner]"
	*
	* Contributor(s):
	*
	* Mike Keith - Add ability to run in OSGi and other environments by making
	* provider discovery a strategy. Also allow providers to be added
	* and removed dynamically.
	*
	* Mike Keith elects to include this software in this distribution under
	* the CDDL license.
	*
	* If you wish your version of this file to be governed by only the CDDL or
	* only the GPL Version 2, indicate your decision by adding "[Contributor]
	* elects to include this software in this distribution under the [CDDL or GPL
	* Version 2] license." 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.persistence;

	// J2SE imports
	import java.io.IOException;
	import java.io.BufferedReader;
	import java.io.InputStream;
	import java.io.InputStreamReader;
	import java.util.Collection;
	import java.util.Iterator;
	import java.util.Set;
	import java.util.Map;
	import java.util.HashSet;
	import java.util.Enumeration;
	import java.net.URL;
	import java.util.regex.Matcher;
	import java.util.regex.Pattern;

	// persistence imports
	import javax.persistence.spi.PersistenceProvider;

	/**
	* Bootstrap class that is used to obtain an {@link EntityManagerFactory}.
	*
	* @since Java Persistence 1.0
	*/
	public class Persistence {

	protected static Set<PersistenceProvider> providers = new HashSet<PersistenceProvider>();

	// Used to resolve and return providers.
	protected static ProviderResolver providerResolver = new DefaultProviderResolver();

	/**
	* Get the resolver being used to obtain the available providers.
	*
	* @return The resolver used to obtain all available providers
	*/
	public static ProviderResolver getProviderResolver() { return providerResolver; }

	/**
	* Set the resolver to an alternate provider resolution strategy (implemented externally).
	* This can be used to override the default resolution strategy.
	*
	* @param resolver The resolver to use when obtaining all available providers
	*/
	public static void setProviderResolver(ProviderResolver resolver) { providerResolver = resolver; }

	/**
	* Create and return an EntityManagerFactory for the
	* named persistence unit.
	*
	* @param persistenceUnitName The name of the persistence unit
	* @return The factory that creates EntityManagers configured
	* according to the specified persistence unit
	*/
	public static EntityManagerFactory createEntityManagerFactory(String persistenceUnitName) {
	return createEntityManagerFactory(persistenceUnitName, null);
	}

	/**
	* Create and return an EntityManagerFactory for the
	* named persistence unit using the given properties.
	*
	* @param persistenceUnitName The name of the persistence unit
	* @param properties Additional properties to use when creating the
	* factory. The values of these properties override any values
	* that may have been configured elsewhere.
	* @return The factory that creates EntityManagers configured
	* according to the specified persistence unit.
	*/
	public static EntityManagerFactory createEntityManagerFactory(
	String persistenceUnitName, Map properties) {

	EntityManagerFactory emf = null;
	if (providers.size() == 0) {
	try{
	providers.addAll(providerResolver.findAllProviders());
	} catch (IOException exc){}
	}
	for (PersistenceProvider provider : providers) {
	emf = provider.createEntityManagerFactory(persistenceUnitName, properties);
	if (emf != null){
	break;
	}
	}
	if (emf == null) {
	throw new PersistenceException("No Persistence provider for EntityManager named " + persistenceUnitName);
	}
	return emf;
	}

	// ====================
	// Internal API methods
	// ====================

	/**
	* Dynamically add a provider to the set of available providers.
	*/
	public static void addProvider(PersistenceProvider provider) {
	providers.add(provider);
	}

	/**
	* Dynamically remove a named provider from the set of available providers.
	*/
	public static void removeProvider(String providerName) {
	for (Iterator<PersistenceProvider> i = providers.iterator(); i.hasNext(); ) {
	if (i.next().getClass().getName().equals(providerName)) {
	i.remove();
	}
	}
	}

	/**
	* Reinitialize to have no providers.
	*/
	public static void resetProviders() {
	providers = new HashSet<PersistenceProvider>();
	}

	// ==============================================================
	// Interface for overriding available provider discovery strategy
	// ==============================================================

	/**
	* Interface used by the Persistence class to obtain all available persistence providers.
	*/
	public static interface ProviderResolver {
	Collection<PersistenceProvider> findAllProviders() throws IOException;
	}

	// =============================
	// Internal implementation class
	// =============================

	/**
	* Default provider resolver class to use when none is explicitly set.
	*
	* Uses the META-INF/services approach as described in the Java Persistence
	* specification. A getResources() call is made on the current context classloader
	* to find the service provider files on the classpath. Any service files found
	* are then read to obtain the classes that implement the persistence provider
	* interface.
	*/
	public static class DefaultProviderResolver implements ProviderResolver {

	public static final String PERSISTENCE_PROVIDER = "javax.persistence.spi.PersistenceProvider";
	public static final String SERVICE_PROVIDER_FILE = "META-INF/services/" + PERSISTENCE_PROVIDER;


	public Collection<PersistenceProvider> findAllProviders() throws IOException {

	ClassLoader loader = Thread.currentThread().getContextClassLoader();
	Enumeration<URL> resources = loader.getResources(SERVICE_PROVIDER_FILE);

	Set<String> providerNames = new HashSet<String>();
	while (resources.hasMoreElements()) {
	URL url = resources.nextElement();
	InputStream is = url.openStream();
	try {
	providerNames.addAll(providerNamesFromReader(new BufferedReader(new InputStreamReader(is))));
	} finally {
	is.close();
	}
	}
	Collection<PersistenceProvider> loadedProviders = new HashSet<PersistenceProvider>();
	for (String s : providerNames) {
	try{
	loadedProviders.add((PersistenceProvider)loader.loadClass(s).newInstance());
	} catch (ClassNotFoundException exc){
	} catch (InstantiationException exc){
	} catch (IllegalAccessException exc){
	}
	}
	return loadedProviders;
	}

	private static final Pattern nonCommentPattern = Pattern.compile("^([^#]+)");

	private Set<String> providerNamesFromReader(BufferedReader reader) throws IOException {
	Set<String> providerNames = new HashSet<String>();
	String line;
	while ((line = reader.readLine()) != null) {
	line = line.trim();
	Matcher m = nonCommentPattern.matcher(line);
	if (m.find()) {
	providerNames.add(m.group().trim());
	}
	}
	return providerNames;
	}
	}
	}