Converting Sun JavaSoft RMI to BEA WebLogic Enterprise RMI Classes

 

It is easier to use BEA WebLogic Enterprise RMI if you have already written classes in the Sun Microsystems JavaSoft reference implementation of RMI. This section explains how to convert Sun JavaSoft RMI classes to WebLogic RMI using the WebLogic RMI Hello World application as an example.

Suppose you have an RMI Hello World example written similar to those found in the Sun JavaSoft documentation distribution. To convert these files for use with BEA WebLogic Enterprise, you must do the following:

• Step 1: Modify the Java source code files

• Step 2: Compile the Java source files

• Step 3: Run the WebLogic RMI compiler on the implementation class

• Step 4: Build and package the application for BEA WebLogic Enterprise

 

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Step 1: Modify the Java source code files

To convert the RMI Hello World example from Sun JavaSoft RMI to BEA WebLogic Enterprise RMI, you must first modify the Java source code files to adjust for the following major differences:

• For lookup and connection bootstrapping, BEA WebLogic Enterprise RMI uses the Java Naming and Directory Interface (JNDI) javax.naming instead of java.rmi.naming

• BEA WebLogic Enterprise RMI uses JNDI javax.naming instead of an RMI registry

• BEA WebLogic Enterprise RMI does not require or recommend use of an RMI security manager

• BEA WebLogic Enterprise RMI classes do not extend UnicastRemoteObject

You need to modify the following Java source code files:

• HelloImpl.java-a Remote Object Implementation

• HelloClient.java-a Client That Invokes Methods on the Remote Object

Note that the file Hello.java, which contains the remote interface, is exactly the same in both the Sun JavaSoft Hello World RMI example and in BEA WebLogic Enterprise RMI. Therefore, you do not need to make any changes to this Java source file-you can use it as is. You will need to recompile it, though, along with the other Java files.

HelloImpl.java-A Remote Object Implementation

To modify this file, compete the following steps:

1. Remove the package imports statements for the following packages, which are not used in BEA WebLogic Enterprise RMI:

   • java.rmi.Naming

   • java.rmi.RMISecurityManager

   • java.rmi.server.UnicastRemoteObject

2. Add package import statements for the following Java Naming and Directory Interface (JNDI) packages, which are needed by BEA WebLogic Enterprise RMI:

   • java.util.Hashtable

   • javax.naming.Context

   • javax.naming.InitialContext

   • javax.naming.NamingException

3. Edit the rest of the code in this file based on the BEA WebLogic Enterprise RMI Hello World example to use the appropriate packages and J2EE features.

   For details, see Step 3: Write the source code for a remote object that implements the remote interface in Developing RMI Applications in BEA WebLogic Enterprise.

HelloClient.java-A Client That Invokes Methods on the Remote Object

The RMI client can be either an applet or a Java client similar to that shown in our BEA WebLogic Enterprise RMI Hello World example. To convert either type of client from Sun JavaSoft RMI to BEA WebLogic Enterprise RMI, you must modify the client file similar to the following to account for some basic differences:

1. Remove the following package import statement, which is not used in BEA WebLogic Enterprise:

   • java.rmi.Naming

2. Add package import statements for the following Java Naming and Directory Interface (JNDI) packages, which are needed by BEA WebLogic Enterprise RMI:

   • java.util.Hashtable

   • javax.naming.Context

   • javax.naming.InitialContext

   • javax.naming.NamingException

3. Edit the rest of the code in this file to use the appropriate packages and J2EE features. In particular, this means using JNDI for the lookup and connection bootstrapping. Once you get the object reference, be sure to use javax.rmi.PortableRemoteObject.narrow to narrow it to the appropriate type.

   For details, see the explanation of the code for the BEA WebLogic Enterprise Hello World RMI client in Step 4: Write the source code for a client that invokes methods on the remote object in Developing RMI Applications in BEA WebLogic Enterprise.

 

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Step 2: Compile the Java source files

Compile the Java source files including the remote object implementation source file (HelloImpl.java), the remote interface that it extends (Hello.java), the RMI client (HelloClient.java or an applet file), along with any other associated Java files needed for the application.

For example, the following command compiles the Java source files in examples/hello and puts the resulting class files under a directory called classes.

javac -d classes examples/hello/*.java

For more information on using the javac compiler to generate BEA WebLogic Enterprise RMI classes, see Step 5: Compile the source code files to create the executable RMI classes in Developing RMI Applications in BEA WebLogic Enterprise.

 

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Step 3: Run the WebLogic RMI compiler on the implementation class

To create a proxy stub file for the client and skeleton file for the server, run the weblogic.rmic compiler on the fully-qualified package names of compiled class files that contain remote object implementations.

For the BEA WebLogic Enterprise RMI Hello World Example, you would run the weblogic.rmic compiler on the class file HelloImpl as follows:

java weblogic.rmic -d . examples.hello.HelloImpl

For more information about stubs and skeletons and about using the WebLogic RMI compiler to generate them, see Step 6: Run the WebLogic RMI compiler on the implementation class to generate stubs and skeletons in Developing RMI Applications in BEA WebLogic Enterprise.

 

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Step 4: Build and package the application for BEA WebLogic Enterprise

Once you have the BEA WebLogic Enterprise RMI class files, all that is left to do is create a bootstrapping mechanism for your application and package the application into a JAR file. For information on how to do this, see the section Building Your RMI Application in the BEA WebLogic Enterprise Environment.