yoko-rmi-impl/src/main/java/org/apache/yoko/rmi/impl/RMIPersistentStub.java

/**
*
* 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.
*/ 

package org.apache.yoko.rmi.impl;

import java.util.logging.Logger;
import java.util.logging.Level;

/**
 * RMIStub's (org.apache.yoko.rmi.impl) implement writeReplace by returning an
 * instance of this class; and this class then implements readResolve to narrow
 * itself to the correct type. This way, object references to RMI exported
 * objects are transferred without loss of the runtime type.
 * 
 * @author Kresten Krab Thorup (krab@eos.dk)
 */
public class RMIPersistentStub extends javax.rmi.CORBA.Stub {
    static final Logger logger = Logger.getLogger(RMIPersistentStub.class
            .getName());
    
    /** the class-type to which this object should be narrow'ed */
    private Class type;

    /** constructor for use by serialization */
    RMIPersistentStub() {
        // System.out.println ("Creating instance of RMIPersistentStub");
    }

    /** constructor used in org.apache.yoko.rmi.impl.RMIStubHandler */
    public RMIPersistentStub(javax.rmi.CORBA.Stub stub, Class type) {
        _set_delegate(stub._get_delegate());
        this.type = type;
    }

    /** narrows this object (once deserialized) to the relevant type */
    public Object readResolve() throws java.lang.ClassNotFoundException {
        // System.out.println ("RMIPersistentStub::readResolve");
        Object result = null;
        try {
            result = javax.rmi.PortableRemoteObject.narrow(this, type);
        } catch (RuntimeException ex) {
            logger.log(Level.WARNING, "Error narrowing object", ex); 
            throw ex;
        }

        // System.out.println ("result is of type "+result.getClass());

        return result;
    }

    /** standard method */
    public String[] _ids() {
        return new String[] { javax.rmi.CORBA.Util.createValueHandler()
                .getRMIRepositoryID(type) };
    }

}