jndistatefactoryimpl.java

JAVA的一些源码 JAVA2 STANDARD EDITION DEVELOPMENT KIT 5.0

/*
 * @(#)JNDIStateFactoryImpl.java	1.6 04/07/27
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.corba.se.impl.presentation.rmi ;

import java.lang.reflect.Field ;

import java.util.Hashtable;

import javax.naming.*;
import javax.naming.spi.StateFactory;

import java.security.AccessController ;
import java.security.PrivilegedAction ;

import javax.rmi.PortableRemoteObject ;

import com.sun.corba.se.spi.orb.ORB;

import java.rmi.Remote;
import java.rmi.server.ExportException;

// XXX This creates a dependendcy on the implementation
// of the CosNaming service provider.
import com.sun.jndi.cosnaming.CNCtx ;

import com.sun.corba.se.spi.presentation.rmi.StubAdapter ;

/**
  * StateFactory that turns java.rmi.Remote objects to org.omg.CORBA.Object.
  * This version works either with standard RMI-IIOP or Dynamic RMI-IIOP.
  * Based on the original com.sun.jndi.cosnaming.RemoteToCorba and
  * com.sun.jndi.toolkit.corba.CorbaUtils.
  *
  * @author Ken Cavanaugh 
  */

public class JNDIStateFactoryImpl implements StateFactory 
{
    private static final Field orbField ;

    static {
	orbField = (Field) AccessController.doPrivileged( 
	    new PrivilegedAction() {
		public Object run() {
		    Field fld = null ;
		    try {
			Class cls = CNCtx.class ;
			fld = cls.getDeclaredField( "_orb" ) ;
			fld.setAccessible( true ) ;
		    } catch (Exception exc) {
			// XXX log exception at FINE
		    }
		    return fld ;
		}
	    } 
	) ;
    }

    public JNDIStateFactoryImpl() 
    {
    }

    /**
     * Returns the CORBA object for a Remote object.
     * If input is not a Remote object, or if Remote object uses JRMP, return null.
     * If the RMI-IIOP library is not available, throw ConfigurationException.
     *
     * @param orig The object to turn into a CORBA object. If not Remote, 
     * 		   or if is a JRMP stub or impl, return null.
     * @param name Ignored
     * @param ctx The non-null CNCtx whose ORB to use.
     * @param env Ignored
     * @return The CORBA object for <tt>orig</tt> or null.
     * @exception ConfigurationException If the CORBA object cannot be obtained
     * 	  due to configuration problems
     * @exception NamingException If some other problem prevented a CORBA
     *    object from being obtained from the Remote object.
     */
    public Object getStateToBind(Object orig, Name name, Context ctx,
	Hashtable<?,?> env) throws NamingException 
    {
	if (orig instanceof org.omg.CORBA.Object)
	    return orig ;

        if (!(orig instanceof Remote)) 
	    // Not for this StateFactory
	    return null ;

	ORB orb = getORB( ctx ) ; 
	if (orb == null)
	    // Wrong kind of context, so just give up and let another StateFactory
	    // try to satisfy getStateToBind.
	    return null ;

	Remote stub = null;

	try {
	    stub = PortableRemoteObject.toStub( (Remote)orig ) ;
	} catch (Exception exc) {
	    // XXX log at FINE level?
	    // Wrong sort of object: just return null to allow another StateFactory
	    // to handle this.  This can happen easily because this StateFactory
	    // is specified for the application, not the service context provider.
	    return null ;
	}

	if (StubAdapter.isStub( stub )) {
	    try {
		StubAdapter.connect( stub, orb ) ; 
	    } catch (Exception exc) {
		if (!(exc instanceof java.rmi.RemoteException)) {
		    // XXX log at FINE level?
		    // Wrong sort of object: just return null to allow another StateFactory
		    // to handle this call.
		    return null ;
		}

		// ignore RemoteException because stub might have already
		// been connected
	    }
	}

	return stub ;
    }

    // This is necessary because the _orb field is package private in 
    // com.sun.jndi.cosnaming.CNCtx.  This is not an ideal solution.
    // The best solution for our ORB is to change the CosNaming provider
    // to use the StubAdapter.  But this has problems as well, because
    // other vendors may use the CosNaming provider with a different ORB
    // entirely.
    private ORB getORB( Context ctx ) 
    {
	ORB orb = null ;

	try {
	    orb = (ORB)orbField.get( ctx ) ;
	} catch (Exception exc) {
	    // XXX log this exception at FINE level
	    // ignore the exception and return null.
	    // Note that the exception may be because ctx
	    // is not a CosNaming context.
	}

	return orb ;
    }
}