/*
 * Copyright 2002-2017 the original author or authors.
 *
 * 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.springframework.transaction.interceptor;

import java.lang.reflect.Method;
import java.util.Properties;
import java.util.concurrent.ConcurrentMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.BeanFactoryAnnotationUtils;
import org.springframework.core.NamedThreadLocal;
import org.springframework.lang.Nullable;
import org.springframework.transaction.NoTransactionException;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.TransactionSystemException;
import org.springframework.transaction.support.CallbackPreferringPlatformTransactionManager;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ConcurrentReferenceHashMap;
import org.springframework.util.StringUtils;

/**
 * Base class for transactional aspects, such as the {@link TransactionInterceptor}
 * or an AspectJ aspect.
 *
 * <p>This enables the underlying Spring transaction infrastructure to be used easily
 * to implement an aspect for any aspect system.
 *
 * <p>Subclasses are responsible for calling methods in this class in the correct order.
 *
 * <p>If no transaction name has been specified in the {@code TransactionAttribute},
 * the exposed name will be the {@code fully-qualified class name + "." + method name}
 * (by default).
 *
 * <p>Uses the <b>Strategy</b> design pattern. A {@code PlatformTransactionManager}
 * implementation will perform the actual transaction management, and a
 * {@code TransactionAttributeSource} is used for determining transaction definitions.
 *
 * <p>A transaction aspect is serializable if its {@code PlatformTransactionManager}
 * and {@code TransactionAttributeSource} are serializable.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Stéphane Nicoll
 * @author Sam Brannen
 * @since 1.1
 * @see #setTransactionManager
 * @see #setTransactionAttributes
 * @see #setTransactionAttributeSource
 */
public abstract class TransactionAspectSupport implements BeanFactoryAware, InitializingBean {

	// NOTE: This class must not implement Serializable because it serves as base
	// class for AspectJ aspects (which are not allowed to implement Serializable)!


	/**
	 * Key to use to store the default transaction manager.
	 */
	private static final Object DEFAULT_TRANSACTION_MANAGER_KEY = new Object();

	/**
	 * Holder to support the {@code currentTransactionStatus()} method,
	 * and to support communication between different cooperating advices
	 * (e.g. before and after advice) if the aspect involves more than a
	 * single method (as will be the case for around advice).
	 */
	private static final ThreadLocal<TransactionInfo> transactionInfoHolder =
			new NamedThreadLocal<>("Current aspect-driven transaction");


	/**
	 * Subclasses can use this to return the current TransactionInfo.
	 * Only subclasses that cannot handle all operations in one method,
	 * such as an AspectJ aspect involving distinct before and after advice,
	 * need to use this mechanism to get at the current TransactionInfo.
	 * An around advice such as an AOP Alliance MethodInterceptor can hold a
	 * reference to the TransactionInfo throughout the aspect method.
	 * <p>A TransactionInfo will be returned even if no transaction was created.
	 * The {@code TransactionInfo.hasTransaction()} method can be used to query this.
	 * <p>To find out about specific transaction characteristics, consider using
	 * TransactionSynchronizationManager's {@code isSynchronizationActive()}
	 * and/or {@code isActualTransactionActive()} methods.
	 * @return TransactionInfo bound to this thread, or {@code null} if none
	 * @see TransactionInfo#hasTransaction()
	 * @see org.springframework.transaction.support.TransactionSynchronizationManager#isSynchronizationActive()
	 * @see org.springframework.transaction.support.TransactionSynchronizationManager#isActualTransactionActive()
	 */
	@Nullable
	protected static TransactionInfo currentTransactionInfo() throws NoTransactionException {
		return transactionInfoHolder.get();
	}

	/**
	 * Return the transaction status of the current method invocation.
	 * Mainly intended for code that wants to set the current transaction
	 * rollback-only but not throw an application exception.
	 * @throws NoTransactionException if the transaction info cannot be found,
	 * because the method was invoked outside an AOP invocation context
	 */
	public static TransactionStatus currentTransactionStatus() throws NoTransactionException {
		TransactionInfo info = currentTransactionInfo();
		if (info == null || info.transactionStatus == null) {
			throw new NoTransactionException("No transaction aspect-managed TransactionStatus in scope");
		}
		return info.transactionStatus;
	}


	protected final Log logger = LogFactory.getLog(getClass());

	@Nullable
	private String transactionManagerBeanName;

	@Nullable
	private PlatformTransactionManager transactionManager;

	@Nullable
	private TransactionAttributeSource transactionAttributeSource;

	@Nullable
	private BeanFactory beanFactory;

	private final ConcurrentMap<Object, PlatformTransactionManager> transactionManagerCache =
			new ConcurrentReferenceHashMap<>(4);


	/**
	 * Specify the name of the default transaction manager bean.
	 */
	public void setTransactionManagerBeanName(@Nullable String transactionManagerBeanName) {
		this.transactionManagerBeanName = transactionManagerBeanName;
	}

	/**
	 * Return the name of the default transaction manager bean.
	 */
	@Nullable
	protected final String getTransactionManagerBeanName() {
		return this.transactionManagerBeanName;
	}

	/**
	 * Specify the <em>default</em> transaction manager to use to drive transactions.
	 * <p>The default transaction manager will be used if a <em>qualifier</em>
	 * has not been declared for a given transaction or if an explicit name for the
	 * default transaction manager bean has not been specified.
	 * @see #setTransactionManagerBeanName
	 */
	public void setTransactionManager(@Nullable PlatformTransactionManager transactionManager) {
		this.transactionManager = transactionManager;
	}

	/**
	 * Return the default transaction manager, or {@code null} if unknown.
	 */
	@Nullable
	public PlatformTransactionManager getTransactionManager() {
		return this.transactionManager;
	}

	/**
	 * Set properties with method names as keys and transaction attribute
	 * descriptors (parsed via TransactionAttributeEditor) as values:
	 * e.g. key = "myMethod", value = "PROPAGATION_REQUIRED,readOnly".
	 * <p>Note: Method names are always applied to the target class,
	 * no matter if defined in an interface or the class itself.
	 * <p>Internally, a NameMatchTransactionAttributeSource will be
	 * created from the given properties.
	 * @see #setTransactionAttributeSource
	 * @see TransactionAttributeEditor
	 * @see NameMatchTransactionAttributeSource
	 */
	public void setTransactionAttributes(Properties transactionAttributes) {
		NameMatchTransactionAttributeSource tas = new NameMatchTransactionAttributeSource();
		tas.setProperties(transactionAttributes);
		this.transactionAttributeSource = tas;
	}

	/**
	 * Set multiple transaction attribute sources which are used to find transaction
	 * attributes. Will build a CompositeTransactionAttributeSource for the given sources.
	 * @see CompositeTransactionAttributeSource
	 * @see MethodMapTransactionAttributeSource
	 * @see NameMatchTransactionAttributeSource
	 * @see org.springframework.transaction.annotation.AnnotationTransactionAttributeSource
	 */
	public void setTransactionAttributeSources(TransactionAttributeSource... transactionAttributeSources) {
		this.transactionAttributeSource = new CompositeTransactionAttributeSource(transactionAttributeSources);
	}

	/**
	 * Set the transaction attribute source which is used to find transaction
	 * attributes. If specifying a String property value, a PropertyEditor
	 * will create a MethodMapTransactionAttributeSource from the value.
	 * @see TransactionAttributeSourceEditor
	 * @see MethodMapTransactionAttributeSource
	 * @see NameMatchTransactionAttributeSource
	 * @see org.springframework.transaction.annotation.AnnotationTransactionAttributeSource
	 */
	public void setTransactionAttributeSource(@Nullable TransactionAttributeSource transactionAttributeSource) {
		this.transactionAttributeSource = transactionAttributeSource;
	}

	/**
	 * Return the transaction attribute source.
	 */
	@Nullable
	public TransactionAttributeSource getTransactionAttributeSource() {
		return this.transactionAttributeSource;
	}

	/**
	 * Set the BeanFactory to use for retrieving PlatformTransactionManager beans.
	 */
	@Override
	public void setBeanFactory(@Nullable BeanFactory beanFactory) {
		this.beanFactory = beanFactory;
	}

	/**
	 * Return the BeanFactory to use for retrieving PlatformTransactionManager beans.
	 */
	@Nullable
	protected final BeanFactory getBeanFactory() {
		return this.beanFactory;
	}

	/**
	 * Check that required properties were set.
	 */
	@Override
	public void afterPropertiesSet() {
		if (getTransactionManager() == null && this.beanFactory == null) {
			throw new IllegalStateException(
					"Set the 'transactionManager' property or make sure to run within a BeanFactory " +
					"containing a PlatformTransactionManager bean!");
		}
		if (getTransactionAttributeSource() == null) {
			throw new IllegalStateException(
					"Either 'transactionAttributeSource' or 'transactionAttributes' is required: " +
					"If there are no transactional methods, then don't use a transaction aspect.");
		}
	}


	/**
	 * General delegate for around-advice-based subclasses, delegating to several other template
	 * methods on this class. Able to handle {@link CallbackPreferringPlatformTransactionManager}
	 * as well as regular {@link PlatformTransactionManager} implementations.
	 * @param method the Method being invoked
	 * @param targetClass the target class that we're invoking the method on
	 * @param invocation the callback to use for proceeding with the target invocation
	 * @return the return value of the method, if any
	 * @throws Throwable propagated from the target invocation
	 */
	@Nullable
	protected Object invokeWithinTransaction(Method method, @Nullable Class<?> targetClass,
			final InvocationCallback invocation) throws Throwable {

		// If the transaction attribute is null, the method is non-transactional.
		TransactionAttributeSource tas = getTransactionAttributeSource();
		final TransactionAttribute txAttr = (tas != null ? tas.getTransactionAttribute(method, targetClass) : null);
		final PlatformTransactionManager tm = determineTransactionManager(txAttr);
		final String joinpointIdentification = methodIdentification(method, targetClass, txAttr);

		if (txAttr == null || !(tm instanceof CallbackPreferringPlatformTransactionManager)) {
			// Standard transaction demarcation with getTransaction and commit/rollback calls.
			TransactionInfo txInfo = createTransactionIfNecessary(tm, txAttr, joinpointIdentification);
			Object retVal = null;
			try {
				// This is an around advice: Invoke the next interceptor in the chain.
				// This will normally result in a target object being invoked.
				retVal = invocation.proceedWithInvocation();
			}
			catch (Throwable ex) {
				// target invocation exception
				completeTransactionAfterThrowing(txInfo, ex);
				throw ex;
			}
			finally {
				cleanupTransactionInfo(txInfo);
			}
			commitTransactionAfterReturning(txInfo);
			return retVal;
		}

		else {
			final ThrowableHolder throwableHolder = new ThrowableHolder();

			// It's a CallbackPreferringPlatformTransactionManager: pass a TransactionCallback in.
			try {
				Object result = ((CallbackPreferringPlatformTransactionManager) tm).execute(txAttr, status -> {
					TransactionInfo txInfo = prepareTransactionInfo(tm, txAttr, joinpointIdentification, status);
					try {
						return invocation.proceedWithInvocation();
					}
					catch (Throwable ex) {
						if (txAttr.rollbackOn(ex)) {
							// A RuntimeException: will lead to a rollback.
							if (ex instanceof RuntimeException) {
								throw (RuntimeException) ex;
							}
							else {
								throw new ThrowableHolderException(ex);
							}
						}
						else {
							// A normal return value: will lead to a commit.
							throwableHolder.throwable = ex;
							return null;
						}
					}
					finally {
						cleanupTransactionInfo(txInfo);
					}
				});

				// Check result state: It might indicate a Throwable to rethrow.
				if (throwableHolder.throwable != null) {
					throw throwableHolder.throwable;
				}
				return result;
			}
			catch (ThrowableHolderException ex) {
				throw ex.getCause();
			}
			catch (TransactionSystemException ex2) {
				if (throwableHolder.throwable != null) {
					logger.error("Application exception overridden by commit exception", throwableHolder.throwable);
					ex2.initApplicationException(throwableHolder.throwable);
				}
				throw ex2;
			}
			catch (Throwable ex2) {
				if (throwableHolder.throwable != null) {
					logger.error("Application exception overridden by commit exception", throwableHolder.throwable);
				}
				throw ex2;
			}
		}
	}

	/**
	 * Clear the cache.
	 */
	protected void clearTransactionManagerCache() {
		this.transactionManagerCache.clear();
		this.beanFactory = null;
	}

	/**
	 * Determine the specific transaction manager to use for the given transaction.
	 */
	@Nullable
	protected PlatformTransactionManager determineTransactionManager(@Nullable TransactionAttribute txAttr) {
		// Do not attempt to lookup tx manager if no tx attributes are set
		if (txAttr == null || this.beanFactory == null) {
			return getTransactionManager();
		}

		String qualifier = txAttr.getQualifier();
		if (StringUtils.hasText(qualifier)) {
			return determineQualifiedTransactionManager(this.beanFactory, qualifier);
		}
		else if (StringUtils.hasText(this.transactionManagerBeanName)) {
			return determineQualifiedTransactionManager(this.beanFactory, this.transactionManagerBeanName);
		}
		else {
			PlatformTransactionManager defaultTransactionManager = getTransactionManager();
			if (defaultTransactionManager == null) {
				defaultTransactionManager = this.transactionManagerCache.get(DEFAULT_TRANSACTION_MANAGER_KEY);
				if (defaultTransactionManager == null) {
					defaultTransactionManager = this.beanFactory.getBean(PlatformTransactionManager.class);
					this.transactionManagerCache.putIfAbsent(
							DEFAULT_TRANSACTION_MANAGER_KEY, defaultTransactionManager);
				}
			}
			return defaultTransactionManager;
		}
	}

	private PlatformTransactionManager determineQualifiedTransactionManager(BeanFactory beanFactory, String qualifier) {
		PlatformTransactionManager txManager = this.transactionManagerCache.get(qualifier);
		if (txManager == null) {
			txManager = BeanFactoryAnnotationUtils.qualifiedBeanOfType(
					beanFactory, PlatformTransactionManager.class, qualifier);
			this.transactionManagerCache.putIfAbsent(qualifier, txManager);
		}
		return txManager;
	}

	private String methodIdentification(Method method, @Nullable Class<?> targetClass,
			@Nullable TransactionAttribute txAttr) {

		String methodIdentification = methodIdentification(method, targetClass);
		if (methodIdentification == null) {
			if (txAttr instanceof DefaultTransactionAttribute) {
				methodIdentification = ((DefaultTransactionAttribute) txAttr).getDescriptor();
			}
			if (methodIdentification == null) {
				methodIdentification = ClassUtils.getQualifiedMethodName(method, targetClass);
			}
		}
		return methodIdentification;
	}

	/**
	 * Convenience method to return a String representation of this Method
	 * for use in logging. Can be overridden in subclasses to provide a
	 * different identifier for the given method.
	 * <p>The default implementation returns {@code null}, indicating the
	 * use of {@link DefaultTransactionAttribute#getDescriptor()} instead,
	 * ending up as {@link ClassUtils#getQualifiedMethodName(Method, Class)}.
	 * @param method the method we're interested in
	 * @param targetClass the class that the method is being invoked on
	 * @return a String representation identifying this method
	 * @see org.springframework.util.ClassUtils#getQualifiedMethodName
	 */
	@Nullable
	protected String methodIdentification(Method method, @Nullable Class<?> targetClass) {
		return null;
	}

	/**
	 * Create a transaction if necessary based on the given TransactionAttribute.
	 * <p>Allows callers to perform custom TransactionAttribute lookups through
	 * the TransactionAttributeSource.
	 * @param txAttr the TransactionAttribute (may be {@code null})
	 * @param joinpointIdentification the fully qualified method name
	 * (used for monitoring and logging purposes)
	 * @return a TransactionInfo object, whether or not a transaction was created.
	 * The {@code hasTransaction()} method on TransactionInfo can be used to
	 * tell if there was a transaction created.
	 * @see #getTransactionAttributeSource()
	 */
	@SuppressWarnings("serial")
	protected TransactionInfo createTransactionIfNecessary(@Nullable PlatformTransactionManager tm,
			@Nullable TransactionAttribute txAttr, final String joinpointIdentification) {

		// If no name specified, apply method identification as transaction name.
		if (txAttr != null && txAttr.getName() == null) {
			txAttr = new DelegatingTransactionAttribute(txAttr) {
				@Override
				public String getName() {
					return joinpointIdentification;
				}
			};
		}

		TransactionStatus status = null;
		if (txAttr != null) {
			if (tm != null) {
				status = tm.getTransaction(txAttr);
			}
			else {
				if (logger.isDebugEnabled()) {
					logger.debug("Skipping transactional joinpoint [" + joinpointIdentification +
							"] because no transaction manager has been configured");
				}
			}
		}
		return prepareTransactionInfo(tm, txAttr, joinpointIdentification, status);
	}

	/**
	 * Prepare a TransactionInfo for the given attribute and status object.
	 * @param txAttr the TransactionAttribute (may be {@code null})
	 * @param joinpointIdentification the fully qualified method name
	 * (used for monitoring and logging purposes)
	 * @param status the TransactionStatus for the current transaction
	 * @return the prepared TransactionInfo object
	 */
	protected TransactionInfo prepareTransactionInfo(@Nullable PlatformTransactionManager tm,
			@Nullable TransactionAttribute txAttr, String joinpointIdentification,
			@Nullable TransactionStatus status) {

		TransactionInfo txInfo = new TransactionInfo(tm, txAttr, joinpointIdentification);
		if (txAttr != null) {
			// We need a transaction for this method...
			if (logger.isTraceEnabled()) {
				logger.trace("Getting transaction for [" + txInfo.getJoinpointIdentification() + "]");
			}
			// The transaction manager will flag an error if an incompatible tx already exists.
			txInfo.newTransactionStatus(status);
		}
		else {
			// The TransactionInfo.hasTransaction() method will return false. We created it only
			// to preserve the integrity of the ThreadLocal stack maintained in this class.
			if (logger.isTraceEnabled())
				logger.trace("Don't need to create transaction for [" + joinpointIdentification +
						"]: This method isn't transactional.");
		}

		// We always bind the TransactionInfo to the thread, even if we didn't create
		// a new transaction here. This guarantees that the TransactionInfo stack
		// will be managed correctly even if no transaction was created by this aspect.
		txInfo.bindToThread();
		return txInfo;
	}

	/**
	 * Execute after successful completion of call, but not after an exception was handled.
	 * Do nothing if we didn't create a transaction.
	 * @param txInfo information about the current transaction
	 */
	protected void commitTransactionAfterReturning(@Nullable TransactionInfo txInfo) {
		if (txInfo != null && txInfo.getTransactionStatus() != null) {
			if (logger.isTraceEnabled()) {
				logger.trace("Completing transaction for [" + txInfo.getJoinpointIdentification() + "]");
			}
			txInfo.getTransactionManager().commit(txInfo.getTransactionStatus());
		}
	}

	/**
	 * Handle a throwable, completing the transaction.
	 * We may commit or roll back, depending on the configuration.
	 * @param txInfo information about the current transaction
	 * @param ex throwable encountered
	 */
	protected void completeTransactionAfterThrowing(@Nullable TransactionInfo txInfo, Throwable ex) {
		if (txInfo != null && txInfo.getTransactionStatus() != null) {
			if (logger.isTraceEnabled()) {
				logger.trace("Completing transaction for [" + txInfo.getJoinpointIdentification() +
						"] after exception: " + ex);
			}
			if (txInfo.transactionAttribute != null && txInfo.transactionAttribute.rollbackOn(ex)) {
				try {
					txInfo.getTransactionManager().rollback(txInfo.getTransactionStatus());
				}
				catch (TransactionSystemException ex2) {
					logger.error("Application exception overridden by rollback exception", ex);
					ex2.initApplicationException(ex);
					throw ex2;
				}
				catch (RuntimeException | Error ex2) {
					logger.error("Application exception overridden by rollback exception", ex);
					throw ex2;
				}
			}
			else {
				// We don't roll back on this exception.
				// Will still roll back if TransactionStatus.isRollbackOnly() is true.
				try {
					txInfo.getTransactionManager().commit(txInfo.getTransactionStatus());
				}
				catch (TransactionSystemException ex2) {
					logger.error("Application exception overridden by commit exception", ex);
					ex2.initApplicationException(ex);
					throw ex2;
				}
				catch (RuntimeException | Error ex2) {
					logger.error("Application exception overridden by commit exception", ex);
					throw ex2;
				}
			}
		}
	}

	/**
	 * Reset the TransactionInfo ThreadLocal.
	 * <p>Call this in all cases: exception or normal return!
	 * @param txInfo information about the current transaction (may be {@code null})
	 */
	protected void cleanupTransactionInfo(@Nullable TransactionInfo txInfo) {
		if (txInfo != null) {
			txInfo.restoreThreadLocalStatus();
		}
	}


	/**
	 * Opaque object used to hold Transaction information. Subclasses
	 * must pass it back to methods on this class, but not see its internals.
	 */
	protected final class TransactionInfo {

		@Nullable
		private final PlatformTransactionManager transactionManager;

		@Nullable
		private final TransactionAttribute transactionAttribute;

		private final String joinpointIdentification;

		@Nullable
		private TransactionStatus transactionStatus;

		@Nullable
		private TransactionInfo oldTransactionInfo;

		public TransactionInfo(@Nullable PlatformTransactionManager transactionManager,
				@Nullable TransactionAttribute transactionAttribute, String joinpointIdentification) {

			this.transactionManager = transactionManager;
			this.transactionAttribute = transactionAttribute;
			this.joinpointIdentification = joinpointIdentification;
		}

		public PlatformTransactionManager getTransactionManager() {
			Assert.state(this.transactionManager != null, "No PlatformTransactionManager set");
			return this.transactionManager;
		}

		@Nullable
		public TransactionAttribute getTransactionAttribute() {
			return this.transactionAttribute;
		}

		/**
		 * Return a String representation of this joinpoint (usually a Method call)
		 * for use in logging.
		 */
		public String getJoinpointIdentification() {
			return this.joinpointIdentification;
		}

		public void newTransactionStatus(@Nullable TransactionStatus status) {
			this.transactionStatus = status;
		}

		@Nullable
		public TransactionStatus getTransactionStatus() {
			return this.transactionStatus;
		}

		/**
		 * Return whether a transaction was created by this aspect,
		 * or whether we just have a placeholder to keep ThreadLocal stack integrity.
		 */
		public boolean hasTransaction() {
			return (this.transactionStatus != null);
		}

		private void bindToThread() {
			// Expose current TransactionStatus, preserving any existing TransactionStatus
			// for restoration after this transaction is complete.
			this.oldTransactionInfo = transactionInfoHolder.get();
			transactionInfoHolder.set(this);
		}

		private void restoreThreadLocalStatus() {
			// Use stack to restore old transaction TransactionInfo.
			// Will be null if none was set.
			transactionInfoHolder.set(this.oldTransactionInfo);
		}

		@Override
		public String toString() {
			return (this.transactionAttribute != null ? this.transactionAttribute.toString() : "No transaction");
		}
	}


	/**
	 * Simple callback interface for proceeding with the target invocation.
	 * Concrete interceptors/aspects adapt this to their invocation mechanism.
	 */
	@FunctionalInterface
	protected interface InvocationCallback {

		Object proceedWithInvocation() throws Throwable;
	}


	/**
	 * Internal holder class for a Throwable in a callback transaction model.
	 */
	private static class ThrowableHolder {

		@Nullable
		public Throwable throwable;
	}


	/**
	 * Internal holder class for a Throwable, used as a RuntimeException to be
	 * thrown from a TransactionCallback (and subsequently unwrapped again).
	 */
	@SuppressWarnings("serial")
	private static class ThrowableHolderException extends RuntimeException {

		public ThrowableHolderException(Throwable throwable) {
			super(throwable);
		}

		@Override
		public String toString() {
			return getCause().toString();
		}
	}

}
