/*
* JBoss, Home of Professional Open Source.
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.mx.interceptor;
import javax.management.MBeanServer;
import javax.management.ObjectName;
import org.jboss.logging.Logger;
import org.jboss.mx.server.Invocation;
/**
* Base class for all interceptors. This class provides some default method
* implementations for interceptors.
*
* @see org.jboss.mx.interceptor.Interceptor
* @see org.jboss.mx.server.MBeanInvoker
*
* @author <a href="mailto:juha@jboss.org">Juha Lindfors</a>.
* @version $Revision: 81026 $
*/
public abstract class AbstractInterceptor
implements Interceptor
{
// Attributes ----------------------------------------------------
/**
* Name for this interceptor.
*/
protected String name = "<no name>";
/**
* Indicates whether this interceptor instance is shared or not.
*/
protected boolean isShared = false;
/**
* Logger reference for interceptor implementations. This reference is
* set by the invoker for non-shared interceptors after construction.
* Shared interceptors will should create their own logger instance.
*/
protected Logger log;
// Constructors --------------------------------------------------
/**
* Constructs a new intereceptor instance. This interceptor is not shared
* in the MBean server.
*/
public AbstractInterceptor()
{
log = Logger.getLogger(getClass());
}
/**
* Constructs a new interceptor instance with a given name. This interceptor
* is not shared in the MBean server.
*
* @param name name of this interceptor
*
* @throws IllegalArgumentException if name contains <tt>null</tt> reference
*/
public AbstractInterceptor(String name)
{
if (name == null || name.equals(""))
throw new IllegalArgumentException("null name");
this.name = name;
log = Logger.getLogger(getClass());
}
// Public --------------------------------------------------------
/**
* Sets a name for this interceptor.
*
* @param name
*/
public void setName(String name)
{
this.name = name;
}
// Interceptor implementation ------------------------------------
/**
* The default invoke implementation queries the invocation object for the
* next interceptor in the chain. If one exists, it is invoked. Otherwise
* the invocation is dispatched to the target object. <p>
*
* Concrete implementations should override this method to implement
* their specific application logic.
*
* @see org.jboss.mx.server.Invocation
* @see org.jboss.mx.server.MBeanInvoker
*
* @param invocation the invocation object send towards the target
* resource by the invoker
*
* @return return value from the target resource
*
* @throws InvocationException This exception wraps any exceptions thrown
* by either the target method of the resource object, or invocation
* interceptors in this interceptor chain. The target exception is
* unwrapped at the {@link org.jboss.mx.server.MBeanInvoker} instance.
*/
public Object invoke(Invocation invocation) throws Throwable
{
Interceptor ic = invocation.nextInterceptor();
// if the invocation object does not provide us with more interceptors,
// invoke the dispatcher that lands the invocation to its final target
// in the resource object
if (ic == null)
return invocation.dispatch();
// see if the next interceptor in the chain is shared
if (ic.isShared())
{
// we require a common interface for all shared interceptors
SharedInterceptor shared = (SharedInterceptor)ic;
// we invoke shared interceptor it via the MBean server bus, get the
// interceptors view to its MBean server
MBeanServer server = shared.getMBeanServer();
// And the object name the interceptor is registered under
ObjectName name = shared.getObjectName();
return server.invoke(
name, "invoke",
new Object[] { invocation }, // args
new String[] { Invocation.class.getName() } // signature
);
}
// invoke non-shared interceptor directly via Java reference
else
{
return ic.invoke(invocation);
}
}
public String getName()
{
return name;
}
public boolean isShared()
{
return isShared;
}
public void setLogger(Logger log)
{
this.log = log;
}
public void init() throws Exception {}
public void start() {}
public void stop() throws Exception {}
public void destroy() {}
// Object overrides ----------------------------------------------
/**
* Returns a string representation of this interceptor instance.
*
* @return string representation
*/
public String toString()
{
String className = getClass().getName();
int index = className.lastIndexOf('.');
return className.substring((index < 0) ? 0 : index) + "[name=" + name + "]";
}
}