/*
 * The contents of this file are subject to the terms 
 * of the Common Development and Distribution License 
 * (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/CDDLv1.0.html or
 * glassfish/bootstrap/legal/CDDLv1.0.txt.
 * See the License for the specific language governing 
 * permissions and limitations under the License.
 * 
 * When distributing Covered Code, include this CDDL 
 * Header Notice in each file and include the License file 
 * at glassfish/bootstrap/legal/CDDLv1.0.txt.  
 * If applicable, add the following below the CDDL Header, 
 * with the fields enclosed by brackets [] replaced by
 * you own identifying information: 
 * "Portions Copyrighted [year] [name of copyright owner]"
 * 
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 */
package com.sun.ejb.containers;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Proxy;
import java.lang.reflect.Method;

import java.util.Iterator;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Logger;
import java.util.logging.Level;

import java.rmi.RemoteException;

import javax.ejb.EJBException;
import javax.ejb.EJBObject;
import com.sun.ejb.Invocation;
import com.sun.ejb.InvocationInfo;
import com.sun.ejb.Container;
import com.sun.ejb.containers.util.MethodMap;
import com.sun.enterprise.EJBObjectToTie;
import com.sun.enterprise.util.LocalStringManagerImpl;
import com.sun.enterprise.util.Utility;
import com.sun.logging.LogDomains;

/** 
 * Handler for EJBObject invocations through EJBObject proxy.
 * 
 *
 * @author Kenneth Saks
 */    

public final class EJBObjectInvocationHandler 
    extends EJBObjectImpl implements InvocationHandler {

    private static Logger logger = LogDomains.getLogger(LogDomains.EJB_LOGGER);

    private static LocalStringManagerImpl localStrings =
        new LocalStringManagerImpl(EJBObjectInvocationHandler.class);

    // Cache reference to invocation info populated during container
    // initialization. This avoids the overhead of building the method 
    // info each time a proxy is created.  
    private MethodMap invocationInfoMap_;

    private Class remoteIntf_;

    /**
     * Constructor used for Remote Home view.
     */
    public EJBObjectInvocationHandler(MethodMap invocationInfoMap,
                                      Class remoteIntf)
        throws Exception {

        invocationInfoMap_ = invocationInfoMap;

        remoteIntf_ = remoteIntf;
        setIsRemoteHomeView(true);

        // NOTE : Container is not set on super-class until after 
        // constructor is called.
    }

    /**
     * Constructor used for Remote Business view.
     */
    public EJBObjectInvocationHandler(MethodMap invocationInfoMap)
        throws Exception {

        invocationInfoMap_ = invocationInfoMap;

        setIsRemoteHomeView(false);

        // NOTE : Container is not set on super-class until after 
        // constructor is called.
    }

    /**
     * This entry point is only used for the Remote Home view.
     */
    public Object invoke(Object proxy, Method method, Object[] args) 
        throws Throwable {

        return invoke(remoteIntf_, method, args);
    }

    Object invoke(Class clientInterface, Method method, Object[] args) 
        throws Throwable {

        ClassLoader originalClassLoader = null;

        // NOTE : be careful with "args" parameter.  It is null
        //        if method signature has 0 arguments.
        try {
            container.onEnteringContainer();

            // In some cases(e.g. if the Home/Remote interfaces appear in
            // a parent of the application's classloader), 
            // ServantLocator.preinvoke() will not be called by the
            // ORB, and therefore BaseContainer.externalPreInvoke will not have
            // been called for this invocation.  In those cases we need to set 
            // the context classloader to the application's classloader before 
            // proceeding. Otherwise, the context classloader could still 
            // reflect the caller's class loader.  
            
            if( Thread.currentThread().getContextClassLoader() != 
                getContainer().getClassLoader() ) {
                originalClassLoader = Utility.setContextClassLoader
                    (getContainer().getClassLoader());
            }
            
            Class methodClass = method.getDeclaringClass();
            if( methodClass == java.lang.Object.class ) {
                return InvocationHandlerUtil.invokeJavaObjectMethod
                    (this, method, args);    
            } 
            
            // Use optimized version of get that takes param count as an 
            // argument.
            InvocationInfo invInfo = (InvocationInfo)
                invocationInfoMap_.get(method, 
                                       ((args != null) ? args.length : 0) );
            
            if( invInfo == null ) {
                throw new RemoteException("Unknown Remote interface method :" 
                                          + method);
            }
            
            if( (methodClass == javax.ejb.EJBObject.class) ||
                invInfo.ejbIntfOverride ) {
                return invokeEJBObjectMethod(method.getName(), args);
            } else if( invInfo.targetMethod1 == null ) {
                Object [] params = new Object[] 
                    { invInfo.ejbName, "Remote", invInfo.method.toString() };
                String errorMsg = localStrings.getLocalString
                    ("ejb.bean_class_method_not_found", "", params);
              
                logger.log(Level.SEVERE, "ejb.bean_class_method_not_found",
                       params);                                   
                throw new RemoteException(errorMsg);           
            }
            
            // Process application-specific method.
            
            Object returnValue = null;
            
            Invocation inv = new Invocation();
            
            inv.isLocal   = false;
            inv.isHome    = false;
            inv.isBusinessInterface = !isRemoteHomeView();
            inv.ejbObject = this;
            inv.method    = method;

            inv.clientInterface = clientInterface;

            // Set cached invocation params.  This will save additional lookups
            // in BaseContainer.
            inv.transactionAttribute = invInfo.txAttr;
            inv.securityPermissions = invInfo.securityPermissions;
            inv.invocationInfo = invInfo;
            inv.beanMethod = invInfo.targetMethod1;
            inv.methodParams = args;
            
            try {
                container.preInvoke(inv);
                returnValue = container.intercept(inv);
            } catch(InvocationTargetException ite) {
                inv.exception = ite.getCause();
                inv.exceptionFromBeanMethod = inv.exception;
            } catch(Throwable t) {
                inv.exception = t;
            } finally {
                container.postInvoke(inv);
            }
            
            if (inv.exception != null) {
                InvocationHandlerUtil.throwRemoteException
                    (inv.exception, method.getExceptionTypes());
            }
            
            return returnValue;
        } finally {
            
            if( originalClassLoader != null ) {
                Utility.setContextClassLoader(originalClassLoader);
            }

            container.onLeavingContainer();
        }
    }


    private Object invokeEJBObjectMethod(String methodName, Object[] args)
        throws Exception
    {
        // Return value is null if target method returns void.
        Object returnValue = null;


        // NOTE : Might be worth optimizing this method check if it
        // turns out to be a bottleneck.  I don't think these methods
        // are called with the frequency that this would be an issue,
        // but it's worth considering.

        if( methodName.equals("getEJBHome") ) {

            returnValue = super.getEJBHome();

        } else if( methodName.equals("getHandle") ) {

            returnValue = super.getHandle();

        } else if( methodName.equals("getPrimaryKey") ) {

            returnValue = super.getPrimaryKey();

        } else if( methodName.equals("isIdentical") ) {

            // boolean isIdentical(EJBObject)
            // Convert the param into an EJBObject.           
            EJBObject other = (EJBObject) args[0];

            returnValue = new Boolean(super.isIdentical(other));

        } else if( methodName.equals("remove") ) {

            super.remove();

        } else {

            throw new RemoteException("unknown EJBObject method = " 
                                      + methodName);
        }

        return returnValue;
    }

}
