jbatch/src/main/java/org/apache/batchee/container/services/ServicesManager.java - geronimo-batchee - Git at Google

 /*
  *
  * Copyright 2012,2013 International Business Machines Corp.
  *
  * See the NOTICE file distributed with this work for additional information
  * regarding copyright ownership. 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.batchee.container.services;

 import static org.apache.batchee.container.util.ClassLoaderAwareHandler.makeLoaderAware;

 import java.io.Closeable;
 import java.io.IOException;
 import java.io.InputStream;
 import java.lang.management.ManagementFactory;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 import java.util.Map;
 import java.util.Properties;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;

 import javax.management.MBeanServer;
 import javax.management.ObjectName;

 import org.apache.batchee.container.exception.BatchContainerRuntimeException;
 import org.apache.batchee.container.exception.BatchContainerServiceException;
 import org.apache.batchee.container.services.callback.SimpleJobExecutionCallbackService;
 import org.apache.batchee.container.services.data.DefaultDataRepresentationService;
 import org.apache.batchee.container.services.executor.DefaultThreadPoolService;
 import org.apache.batchee.container.services.factory.CDIBatchArtifactFactory;
 import org.apache.batchee.container.services.factory.DefaultBatchArtifactFactory;
 import org.apache.batchee.container.services.kernel.DefaultBatchKernel;
 import org.apache.batchee.container.services.loader.DefaultJobXMLLoaderService;
 import org.apache.batchee.container.services.locator.SingletonLocator;
 import org.apache.batchee.container.services.persistence.MemoryPersistenceManagerService;
 import org.apache.batchee.container.services.status.DefaultJobStatusManager;
 import org.apache.batchee.container.services.transaction.DefaultBatchTransactionService;
 import org.apache.batchee.container.util.BatchContainerConstants;
 import org.apache.batchee.jmx.BatchEE;
 import org.apache.batchee.jmx.BatchEEMBean;
 import org.apache.batchee.jmx.BatchEEMBeanImpl;
 import org.apache.batchee.spi.BatchArtifactFactory;
 import org.apache.batchee.spi.BatchService;
 import org.apache.batchee.spi.BatchThreadPoolService;
 import org.apache.batchee.spi.DataRepresentationService;
 import org.apache.batchee.spi.JobExecutionCallbackService;
 import org.apache.batchee.spi.JobXMLLoaderService;
 import org.apache.batchee.spi.PersistenceManagerService;
 import org.apache.batchee.spi.TransactionManagementService;

 public class ServicesManager implements BatchContainerConstants {
     private final static Logger LOGGER = Logger.getLogger(ServicesManager.class.getName());

     private static final String SERVICES_CONFIGURATION_FILE = "batchee.properties";

     // Use class names instead of Class objects to not drag in any dependencies and to easily interact with properties
     private static final Map<String, String> SERVICE_IMPL_CLASS_NAMES = new ConcurrentHashMap<String, String>();
     static {
         SERVICE_IMPL_CLASS_NAMES.put(TransactionManagementService.class.getName(), DefaultBatchTransactionService.class.getName());
         SERVICE_IMPL_CLASS_NAMES.put(PersistenceManagerService.class.getName(), MemoryPersistenceManagerService.class.getName());
         SERVICE_IMPL_CLASS_NAMES.put(JobStatusManagerService.class.getName(), DefaultJobStatusManager.class.getName());
         SERVICE_IMPL_CLASS_NAMES.put(BatchThreadPoolService.class.getName(), DefaultThreadPoolService.class.getName());
         SERVICE_IMPL_CLASS_NAMES.put(BatchKernelService.class.getName(), DefaultBatchKernel.class.getName());
         SERVICE_IMPL_CLASS_NAMES.put(JobXMLLoaderService.class.getName(), DefaultJobXMLLoaderService.class.getName());
         SERVICE_IMPL_CLASS_NAMES.put(JobExecutionCallbackService.class.getName(), SimpleJobExecutionCallbackService.class.getName());
         SERVICE_IMPL_CLASS_NAMES.put(DataRepresentationService.class.getName(), DefaultDataRepresentationService.class.getName());
         try {
             Thread.currentThread().getContextClassLoader().loadClass("javax.enterprise.inject.spi.BeanManager");
             SERVICE_IMPL_CLASS_NAMES.put(BatchArtifactFactory.class.getName(), CDIBatchArtifactFactory.class.getName());
         } catch (final Throwable th) {
             SERVICE_IMPL_CLASS_NAMES.put(BatchArtifactFactory.class.getName(), DefaultBatchArtifactFactory.class.getName());
         }

         setServicesManagerLocator(SingletonLocator.INSTANCE); // default init
     }

     private static ServicesManagerLocator servicesManagerLocator;

     private ObjectName jmxName;
     private ClassLoader loader = null;

     // designed to be used from app or a server
     public static void setServicesManagerLocator(final ServicesManagerLocator locator) {
         servicesManagerLocator = locator;
     }

     public static ServicesManager find() {
         return servicesManagerLocator.find();
     }

     public static String value(final String key, final String defaultValue) {
         return servicesManagerLocator.find().batchRuntimeConfig.getProperty(key, defaultValue);
     }

     // Declared 'volatile' to allow use in double-checked locking.  This 'isInited'
     // refers to whether the configuration has been hardened and possibly the
     // first service impl loaded, not whether the instance has merely been instantiated.
     private final byte[] isInitedLock = new byte[0];
     private volatile boolean isInited = false;

     private Properties batchRuntimeConfig;
     private boolean logServices;

     // Registry of all current services
     private final ConcurrentHashMap<String, BatchService> serviceRegistry = new ConcurrentHashMap<String, BatchService>();

     /**
      * Init doesn't actually load the service impls, which are still loaded lazily.   What it does is it
      * hardens the config.  This is necessary since the batch runtime by and large is not dynamically
      * configurable, (e.g. via MBeans).  Things like the database config used by the batch runtime's
      * persistent store are hardened then, as are the names of the service impls to use.
      */
     public void init(final Properties props) {
         // Use double-checked locking with volatile.
         if (!isInited) {
             synchronized (isInitedLock) {
                 if (!isInited) {
                     batchRuntimeConfig = new Properties();

                     batchRuntimeConfig.putAll(SERVICE_IMPL_CLASS_NAMES); // defaults

                     loader = Thread.currentThread().getContextClassLoader();

                     // file in the classloader
                     final InputStream batchServicesListInputStream = loader.getResourceAsStream(SERVICES_CONFIGURATION_FILE);
                     if (batchServicesListInputStream != null) {
                         try {
                             batchRuntimeConfig.load(batchServicesListInputStream);
                         } catch (final Exception e) {
                             LOGGER.config("Error loading " + SERVICES_CONFIGURATION_FILE + " Exception=" + e.toString());
                         } finally {
                             try {
                                 batchServicesListInputStream.close();
                             } catch (final IOException e) {
                                 // no-op
                             }
                         }
                     }

                     // API overriding
                     if (props != null) {
                         batchRuntimeConfig.putAll(props);
                     }

                     // JVM instance overriding
                     batchRuntimeConfig.putAll(System.getProperties());

                     logServices = Boolean.parseBoolean(batchRuntimeConfig.getProperty("batchee.service-manager.log", "false"));

                     if (Boolean.parseBoolean(batchRuntimeConfig.getProperty("org.apache.batchee.jmx", "true"))) {
                         try {
                             final MBeanServer platformMBeanServer = ManagementFactory.getPlatformMBeanServer();
                             final String app = batchRuntimeConfig.getProperty("org.apache.batchee.jmx.application", "");
                             if (app.isEmpty()) {
                                 jmxName = new ObjectName(BatchEEMBean.DEFAULT_OBJECT_NAME);
                             } else {
                                 jmxName = new ObjectName(BatchEEMBean.DEFAULT_OBJECT_NAME + ",application=" + app);
                             }

                             if (!platformMBeanServer.isRegistered(jmxName)) {
                                 platformMBeanServer.registerMBean(
                                         new BatchEE(
                                                 makeLoaderAware(BatchEEMBean.class, new Class<?>[]{ BatchEEMBean.class },
                                                         BatchEEMBeanImpl.INSTANCE)),
                                         jmxName);
                             } else {
                                 jmxName = null;
                                 LOGGER.warning("You didn't specify org.apache.batchee.jmx.application and JMX is already registered, skipping");
                             }
                         } catch (final Exception e) {
                             throw new IllegalStateException(e);
                         }
                     }

                     isInited = Boolean.TRUE;
                 }
             }
         }
     }

     public void close() {
         if (isInited) {
             synchronized (isInitedLock) {
                 if (isInited) {
                     service(BatchThreadPoolService.class).shutdown();
                     synchronized (serviceRegistry) {
                         for (final Object service : serviceRegistry.values()) {
                             if (Closeable.class.isInstance(service)) {
                                 try {
                                     Closeable.class.cast(service).close();
                                 } catch (IOException e) { // don't make it blocking, on j7 we can use suppressed maybe?
                                     LOGGER.log(Level.SEVERE, e.getMessage(), e);
                                 }
                             }
                         }
                     }


                     if (jmxName != null) { // unregister jmx bean if deployed in an app
                         final MBeanServer jmx = ManagementFactory.getPlatformMBeanServer();
                         try {
                             jmx.unregisterMBean(jmxName);
                         } catch (final Exception e) {
                             // no-op
                         }
                     }
                     isInited = false;
                 }
             }
         }
     }

     public <T extends BatchService> T service(final Class<T> clazz) throws BatchContainerServiceException {
         T service = clazz.cast(serviceRegistry.get(clazz.getName()));
         if (service == null) {
             // Probably don't want to be loading two on two different threads so lock the whole table.
             synchronized (serviceRegistry) {
                 service = clazz.cast(serviceRegistry.get(clazz.getName()));
                 if (service == null) {
                     service = loadService(clazz);
                     service.init(batchRuntimeConfig);
                     serviceRegistry.putIfAbsent(clazz.getName(), service);
                 }
             }
         }
         return service;
     }

     private <T extends BatchService> T loadService(final Class<T> serviceType) {
         final Object existing = batchRuntimeConfig.get(serviceType.getName());
         if (serviceType.isInstance(existing)) {
             return serviceType.cast(existing);
         }

         T service = null;
         String className = batchRuntimeConfig.getProperty(serviceType.getSimpleName()); // short name first
         try {
             if (className != null) {
                 service = load(serviceType, className);
             } else {
                 className = String.class.cast(existing);
                 if (className != null) {
                     service = load(serviceType, className);
                 }
             }
         } catch (final Throwable e1) {
             handleBatchContainerRuntimeException(e1);
             throw new IllegalArgumentException("Could not instantiate service " + className + " due to exception: " + e1);
         }

         if (service == null) {
             throw new BatchContainerRuntimeException("Instantiate of service=: " + className + " returned null. Aborting...");
         }

         if (logServices) {
             LOGGER.info("Using " + service + " (" + className + ") as " + serviceType.getName());
         }

         return service;
     }

     private <T> T load(final Class<T> expected, final String className) throws Exception {
         Class<?> cls = null;

         try {
             cls = getLoader().loadClass(className);
         } catch (Exception e) {
             handleBatchContainerRuntimeException(e);
             throw new BatchContainerRuntimeException("Could not load Service class " + className + ". Make sure it exists", e);
         }
         Throwable problem = null;
         try {
             final Constructor<?> constructor = cls.getConstructor(ServicesManager.class);
             return expected.cast(constructor.newInstance(this));
         } catch (final Throwable th) {
             handleBatchContainerRuntimeException(th);
             // remember the first problem and try no arg constructor
             problem = th;
         }
         try {
             if (cls.getConstructor() != null) {
                 return expected.cast(cls.newInstance());
             }
         } catch (Throwable th) {
             handleBatchContainerRuntimeException(th);
             // default ct works neither, lets report the original problem
         }
         throw new BatchContainerRuntimeException("Service class " + className + " cannnot be loaded", problem);
     }

     /**
      * prevent BatchContainerRuntimeExceptions to get swallowed
      */
     private void handleBatchContainerRuntimeException(Throwable e) throws BatchContainerRuntimeException {
         if (e instanceof BatchContainerRuntimeException) {
             throw (BatchContainerRuntimeException) e;
         }
         if (e instanceof InvocationTargetException) {
             InvocationTargetException ite = (InvocationTargetException) e;
             if (ite.getCause() instanceof BatchContainerRuntimeException) {
                 throw (BatchContainerRuntimeException) ite.getCause();
             }
         }
         // else all is fine
     }

     private ClassLoader getLoader() {
         if (loader != null) {
             return loader;
         }
         return Thread.currentThread().getContextClassLoader();
     }
 }
	/*
	*
	* Copyright 2012,2013 International Business Machines Corp.
	*
	* See the NOTICE file distributed with this work for additional information
	* regarding copyright ownership. 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.batchee.container.services;

	import static org.apache.batchee.container.util.ClassLoaderAwareHandler.makeLoaderAware;

	import java.io.Closeable;
	import java.io.IOException;
	import java.io.InputStream;
	import java.lang.management.ManagementFactory;
	import java.lang.reflect.Constructor;
	import java.lang.reflect.InvocationTargetException;
	import java.util.Map;
	import java.util.Properties;
	import java.util.concurrent.ConcurrentHashMap;
	import java.util.logging.Level;
	import java.util.logging.Logger;

	import javax.management.MBeanServer;
	import javax.management.ObjectName;

	import org.apache.batchee.container.exception.BatchContainerRuntimeException;
	import org.apache.batchee.container.exception.BatchContainerServiceException;
	import org.apache.batchee.container.services.callback.SimpleJobExecutionCallbackService;
	import org.apache.batchee.container.services.data.DefaultDataRepresentationService;
	import org.apache.batchee.container.services.executor.DefaultThreadPoolService;
	import org.apache.batchee.container.services.factory.CDIBatchArtifactFactory;
	import org.apache.batchee.container.services.factory.DefaultBatchArtifactFactory;
	import org.apache.batchee.container.services.kernel.DefaultBatchKernel;
	import org.apache.batchee.container.services.loader.DefaultJobXMLLoaderService;
	import org.apache.batchee.container.services.locator.SingletonLocator;
	import org.apache.batchee.container.services.persistence.MemoryPersistenceManagerService;
	import org.apache.batchee.container.services.status.DefaultJobStatusManager;
	import org.apache.batchee.container.services.transaction.DefaultBatchTransactionService;
	import org.apache.batchee.container.util.BatchContainerConstants;
	import org.apache.batchee.jmx.BatchEE;
	import org.apache.batchee.jmx.BatchEEMBean;
	import org.apache.batchee.jmx.BatchEEMBeanImpl;
	import org.apache.batchee.spi.BatchArtifactFactory;
	import org.apache.batchee.spi.BatchService;
	import org.apache.batchee.spi.BatchThreadPoolService;
	import org.apache.batchee.spi.DataRepresentationService;
	import org.apache.batchee.spi.JobExecutionCallbackService;
	import org.apache.batchee.spi.JobXMLLoaderService;
	import org.apache.batchee.spi.PersistenceManagerService;
	import org.apache.batchee.spi.TransactionManagementService;

	public class ServicesManager implements BatchContainerConstants {
	private final static Logger LOGGER = Logger.getLogger(ServicesManager.class.getName());

	private static final String SERVICES_CONFIGURATION_FILE = "batchee.properties";

	// Use class names instead of Class objects to not drag in any dependencies and to easily interact with properties
	private static final Map<String, String> SERVICE_IMPL_CLASS_NAMES = new ConcurrentHashMap<String, String>();
	static {
	SERVICE_IMPL_CLASS_NAMES.put(TransactionManagementService.class.getName(), DefaultBatchTransactionService.class.getName());
	SERVICE_IMPL_CLASS_NAMES.put(PersistenceManagerService.class.getName(), MemoryPersistenceManagerService.class.getName());
	SERVICE_IMPL_CLASS_NAMES.put(JobStatusManagerService.class.getName(), DefaultJobStatusManager.class.getName());
	SERVICE_IMPL_CLASS_NAMES.put(BatchThreadPoolService.class.getName(), DefaultThreadPoolService.class.getName());
	SERVICE_IMPL_CLASS_NAMES.put(BatchKernelService.class.getName(), DefaultBatchKernel.class.getName());
	SERVICE_IMPL_CLASS_NAMES.put(JobXMLLoaderService.class.getName(), DefaultJobXMLLoaderService.class.getName());
	SERVICE_IMPL_CLASS_NAMES.put(JobExecutionCallbackService.class.getName(), SimpleJobExecutionCallbackService.class.getName());
	SERVICE_IMPL_CLASS_NAMES.put(DataRepresentationService.class.getName(), DefaultDataRepresentationService.class.getName());
	try {
	Thread.currentThread().getContextClassLoader().loadClass("javax.enterprise.inject.spi.BeanManager");
	SERVICE_IMPL_CLASS_NAMES.put(BatchArtifactFactory.class.getName(), CDIBatchArtifactFactory.class.getName());
	} catch (final Throwable th) {
	SERVICE_IMPL_CLASS_NAMES.put(BatchArtifactFactory.class.getName(), DefaultBatchArtifactFactory.class.getName());
	}

	setServicesManagerLocator(SingletonLocator.INSTANCE); // default init
	}

	private static ServicesManagerLocator servicesManagerLocator;

	private ObjectName jmxName;
	private ClassLoader loader = null;

	// designed to be used from app or a server
	public static void setServicesManagerLocator(final ServicesManagerLocator locator) {
	servicesManagerLocator = locator;
	}

	public static ServicesManager find() {
	return servicesManagerLocator.find();
	}

	public static String value(final String key, final String defaultValue) {
	return servicesManagerLocator.find().batchRuntimeConfig.getProperty(key, defaultValue);
	}

	// Declared 'volatile' to allow use in double-checked locking. This 'isInited'
	// refers to whether the configuration has been hardened and possibly the
	// first service impl loaded, not whether the instance has merely been instantiated.
	private final byte[] isInitedLock = new byte[0];
	private volatile boolean isInited = false;

	private Properties batchRuntimeConfig;
	private boolean logServices;

	// Registry of all current services
	private final ConcurrentHashMap<String, BatchService> serviceRegistry = new ConcurrentHashMap<String, BatchService>();

	/**
	* Init doesn't actually load the service impls, which are still loaded lazily. What it does is it
	* hardens the config. This is necessary since the batch runtime by and large is not dynamically
	* configurable, (e.g. via MBeans). Things like the database config used by the batch runtime's
	* persistent store are hardened then, as are the names of the service impls to use.
	*/
	public void init(final Properties props) {
	// Use double-checked locking with volatile.
	if (!isInited) {
	synchronized (isInitedLock) {
	if (!isInited) {
	batchRuntimeConfig = new Properties();

	batchRuntimeConfig.putAll(SERVICE_IMPL_CLASS_NAMES); // defaults

	loader = Thread.currentThread().getContextClassLoader();

	// file in the classloader
	final InputStream batchServicesListInputStream = loader.getResourceAsStream(SERVICES_CONFIGURATION_FILE);
	if (batchServicesListInputStream != null) {
	try {
	batchRuntimeConfig.load(batchServicesListInputStream);
	} catch (final Exception e) {
	LOGGER.config("Error loading " + SERVICES_CONFIGURATION_FILE + " Exception=" + e.toString());
	} finally {
	try {
	batchServicesListInputStream.close();
	} catch (final IOException e) {
	// no-op
	}
	}
	}

	// API overriding
	if (props != null) {
	batchRuntimeConfig.putAll(props);
	}

	// JVM instance overriding
	batchRuntimeConfig.putAll(System.getProperties());

	logServices = Boolean.parseBoolean(batchRuntimeConfig.getProperty("batchee.service-manager.log", "false"));

	if (Boolean.parseBoolean(batchRuntimeConfig.getProperty("org.apache.batchee.jmx", "true"))) {
	try {
	final MBeanServer platformMBeanServer = ManagementFactory.getPlatformMBeanServer();
	final String app = batchRuntimeConfig.getProperty("org.apache.batchee.jmx.application", "");
	if (app.isEmpty()) {
	jmxName = new ObjectName(BatchEEMBean.DEFAULT_OBJECT_NAME);
	} else {
	jmxName = new ObjectName(BatchEEMBean.DEFAULT_OBJECT_NAME + ",application=" + app);
	}

	if (!platformMBeanServer.isRegistered(jmxName)) {
	platformMBeanServer.registerMBean(
	new BatchEE(
	makeLoaderAware(BatchEEMBean.class, new Class<?>[]{ BatchEEMBean.class },
	BatchEEMBeanImpl.INSTANCE)),
	jmxName);
	} else {
	jmxName = null;
	LOGGER.warning("You didn't specify org.apache.batchee.jmx.application and JMX is already registered, skipping");
	}
	} catch (final Exception e) {
	throw new IllegalStateException(e);
	}
	}

	isInited = Boolean.TRUE;
	}
	}
	}
	}

	public void close() {
	if (isInited) {
	synchronized (isInitedLock) {
	if (isInited) {
	service(BatchThreadPoolService.class).shutdown();
	synchronized (serviceRegistry) {
	for (final Object service : serviceRegistry.values()) {
	if (Closeable.class.isInstance(service)) {
	try {
	Closeable.class.cast(service).close();
	} catch (IOException e) { // don't make it blocking, on j7 we can use suppressed maybe?
	LOGGER.log(Level.SEVERE, e.getMessage(), e);
	}
	}
	}
	}


	if (jmxName != null) { // unregister jmx bean if deployed in an app
	final MBeanServer jmx = ManagementFactory.getPlatformMBeanServer();
	try {
	jmx.unregisterMBean(jmxName);
	} catch (final Exception e) {
	// no-op
	}
	}
	isInited = false;
	}
	}
	}
	}

	public <T extends BatchService> T service(final Class<T> clazz) throws BatchContainerServiceException {
	T service = clazz.cast(serviceRegistry.get(clazz.getName()));
	if (service == null) {
	// Probably don't want to be loading two on two different threads so lock the whole table.
	synchronized (serviceRegistry) {
	service = clazz.cast(serviceRegistry.get(clazz.getName()));
	if (service == null) {
	service = loadService(clazz);
	service.init(batchRuntimeConfig);
	serviceRegistry.putIfAbsent(clazz.getName(), service);
	}
	}
	}
	return service;
	}

	private <T extends BatchService> T loadService(final Class<T> serviceType) {
	final Object existing = batchRuntimeConfig.get(serviceType.getName());
	if (serviceType.isInstance(existing)) {
	return serviceType.cast(existing);
	}

	T service = null;
	String className = batchRuntimeConfig.getProperty(serviceType.getSimpleName()); // short name first
	try {
	if (className != null) {
	service = load(serviceType, className);
	} else {
	className = String.class.cast(existing);
	if (className != null) {
	service = load(serviceType, className);
	}
	}
	} catch (final Throwable e1) {
	handleBatchContainerRuntimeException(e1);
	throw new IllegalArgumentException("Could not instantiate service " + className + " due to exception: " + e1);
	}

	if (service == null) {
	throw new BatchContainerRuntimeException("Instantiate of service=: " + className + " returned null. Aborting...");
	}

	if (logServices) {
	LOGGER.info("Using " + service + " (" + className + ") as " + serviceType.getName());
	}

	return service;
	}

	private <T> T load(final Class<T> expected, final String className) throws Exception {
	Class<?> cls = null;

	try {
	cls = getLoader().loadClass(className);
	} catch (Exception e) {
	handleBatchContainerRuntimeException(e);
	throw new BatchContainerRuntimeException("Could not load Service class " + className + ". Make sure it exists", e);
	}
	Throwable problem = null;
	try {
	final Constructor<?> constructor = cls.getConstructor(ServicesManager.class);
	return expected.cast(constructor.newInstance(this));
	} catch (final Throwable th) {
	handleBatchContainerRuntimeException(th);
	// remember the first problem and try no arg constructor
	problem = th;
	}
	try {
	if (cls.getConstructor() != null) {
	return expected.cast(cls.newInstance());
	}
	} catch (Throwable th) {
	handleBatchContainerRuntimeException(th);
	// default ct works neither, lets report the original problem
	}
	throw new BatchContainerRuntimeException("Service class " + className + " cannnot be loaded", problem);
	}

	/**
	* prevent BatchContainerRuntimeExceptions to get swallowed
	*/
	private void handleBatchContainerRuntimeException(Throwable e) throws BatchContainerRuntimeException {
	if (e instanceof BatchContainerRuntimeException) {
	throw (BatchContainerRuntimeException) e;
	}
	if (e instanceof InvocationTargetException) {
	InvocationTargetException ite = (InvocationTargetException) e;
	if (ite.getCause() instanceof BatchContainerRuntimeException) {
	throw (BatchContainerRuntimeException) ite.getCause();
	}
	}
	// else all is fine
	}

	private ClassLoader getLoader() {
	if (loader != null) {
	return loader;
	}
	return Thread.currentThread().getContextClassLoader();
	}
	}