package org.apache.fulcrum.yaafi.framework.interceptor;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import org.apache.fulcrum.yaafi.framework.util.Validate;
import org.apache.fulcrum.yaafi.framework.util.ToStringBuilder;
/**
* The InvocationHandler invoked when a service call is routed through
* the dynamic proxy.
*
* @author <a href="mailto:siegfried.goeschl@it20one.at">Siegfried Goeschl </a>
*/
public class AvalonInterceptorInvocationHandler implements InvocationHandler
{
/** the name of the service */
private String serviceName;
/** the shorthand of the service */
private String serviceShorthand;
/** the real service implementation */
private Object serviceDelegate;
/** the list of interceptors to be invoked */
private AvalonInterceptorService [] serviceInterceptorList;
/** counts the current transactions */
private static volatile long transactionCounter = 0L;
/** the current transaction id */
private Long transactionId;
/**
* Constructor.
*
* @param serviceName the name of the service
* @param serviceShorthand the shorthand of the service being intercepted
* @param serviceDelegate the real service implementation
* @param serviceInterceptorList the list of interceptors to be invoked
*/
public AvalonInterceptorInvocationHandler(
String serviceName,
String serviceShorthand,
Object serviceDelegate,
AvalonInterceptorService [] serviceInterceptorList )
{
Validate.notEmpty(serviceName,"serviceName");
Validate.notEmpty(serviceShorthand,"serviceShorthand");
Validate.notNull(serviceDelegate,"serviceDelegate");
Validate.notNull(serviceInterceptorList,"serviceInterceptorList");
this.serviceName = serviceName;
this.serviceShorthand = serviceShorthand;
this.serviceDelegate = serviceDelegate;
this.serviceInterceptorList = serviceInterceptorList;
}
/**
* @return Returns the delegate.
*/
public Object getServiceDelegate()
{
return this.serviceDelegate;
}
/**
* @return Returns the serviceInterceptorList.
*/
public AvalonInterceptorService [] getServiceInterceptorList()
{
return serviceInterceptorList;
}
/**
* @return Returns the serviceName.
*/
public String getServiceName()
{
return serviceName;
}
/**
* @return Returns the serviceShorthand.
*/
public String getServiceShorthand()
{
return serviceShorthand;
}
/**
* @return Returns the transaction id
*/
public Long getTransactionId()
{
return transactionId;
}
/**
* @see java.lang.Object#toString()
*/
public String toString()
{
ToStringBuilder toStringBuilder = new ToStringBuilder(this);
toStringBuilder.append("serviceShorthand",this.serviceShorthand);
toStringBuilder.append("serviceName",this.serviceName);
toStringBuilder.append("serviceDelegate",this.serviceDelegate);
toStringBuilder.append("transactionId",this.transactionId);
return toStringBuilder.toString();
}
/**
* @see java.lang.reflect.InvocationHandler#invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
*/
public Object invoke(Object proxy, Method method, Object [] args)
throws Throwable
{
Object result = null;
// create the interceptor context for current method call
AvalonInterceptorContext context = new AvalonInterceptorContextImpl(
this.getServiceName(),
this.getServiceShorthand(),
this.getServiceDelegate(),
method,
args
);
// if no transaction id is currently define we create a new one
boolean hasCreatedTransaction = this.createTransactionId(context);
try
{
context.incrementInvocationDepth();
this.onEntry(context);
result = method.invoke( this.getServiceDelegate(), args );
this.onExit(context,result);
return result;
}
catch (InvocationTargetException e)
{
this.onError(context,e.getTargetException());
throw e.getTargetException();
}
finally
{
// decrement the service invocation depth
context.decrementInvocationDepth();
// reset the transaction id if we have created it before
if( hasCreatedTransaction )
{
context.clearTransactionId();
}
}
}
/**
* Invoke the onEntry method on all service interceptors.
*
* @param context the current interceptor context
*/
private void onEntry( AvalonInterceptorContext context )
{
for( int i=0; i<this.getServiceInterceptorList().length; i++ )
{
this.getServiceInterceptorList()[i].onEntry(context);
}
}
/**
* Invoke the onExit method on all service interceptors.
*
* @param context the current interceptor context
* @param result the result
*/
private void onExit( AvalonInterceptorContext context, Object result )
{
for( int i=this.getServiceInterceptorList().length-1; i>=0; i-- )
{
this.getServiceInterceptorList()[i].onExit(context,result);
}
}
/**
* Invoke the onError method on all service interceptors.
*
* @param context the current interceptor context
* @param t the resulting exception
*/
private void onError( AvalonInterceptorContext context, Throwable t )
{
for( int i=this.getServiceInterceptorList().length-1; i>=0; i-- )
{
this.getServiceInterceptorList()[i].onError(context,t);
}
}
/**
* Creates a transaction id using the thread local storage
* @param context current interceptor context
* @return was a new transaction started
*/
private boolean createTransactionId(AvalonInterceptorContext context)
{
Long currentTransactionId = null;
if( context.hasTransactionId() == false )
{
// create a new transaction id
currentTransactionId = new Long(
++AvalonInterceptorInvocationHandler.transactionCounter
);
// store it in the TLS
context.setTransactionId(currentTransactionId);
return true;
}
return false;
}
}