Complete Part 1 And Part 2 Part 1. ======= The first part of this lab takes you through the steps of deploying a simple Java RMI application. It is recommended that you complete this introductory exercise before attempting part 2. Note that the use of rmic is now optional. In other words, in the most recent versions of Java, you do not need to generate the stub file and copy it to the client. The stub or proxy is available via the client side lookup on the registry. This is a very simple Java RMI application that illustrates the use of interfaces and the RMIC tool. Note that it is designed to work from the command prompt. If working on a PC, you will need to have the java bin directory in your path variable. 1. Create two directories from a DOS or Unix prompt. Name one directory 'RMILabServer' and the other directory 'RMILabClient'. 2. Within the server directory, save the following three classes. //************************************************************ // Calculator.java Interface for a Calculator import java.rmi.*; public interface Calculator extends Remote { // this method will be called from remote clients int add (int x, int y) throws RemoteException; } //************************************************************* // CalculatorServant.java // A Remote object class that implements Calculator. import java.rmi.*; import java.rmi.server.UnicastRemoteObject; public class CalculatorServant extends UnicastRemoteObject implements Calculator { public CalculatorServant() throws RemoteException { } public int add(int x, int y) throws RemoteException { System.out.println("Got request to add " + x + " and " + y); return x + y; } } //************************************************************** // CalculatorServer.java Serve remote Calculator // Creates a calculator object and gives // it a name in the registry. import java.rmi.*; public class CalculatorServer { public static void main(String args[]){ System.out.println("Calculator Server Running"); try{ // create the servant Calculator c = new CalculatorServant(); System.out.println("Created Calculator object"); System.out.println("Placing in registry"); // publish to registry Naming.rebind("CoolCalculator", c); System.out.println("CalculatorServant object ready"); }catch(Exception e) { System.out.println("CalculatorServer error main " + e.getMessage()); } } } Compile all the code with the command "javac *.*". Run RMIC on the servant class with the command "rmic -v1.2 CalculatorServant". Copy the interface Calculator.java and the stub class to the client. The stub will be called CalculatorServant_Stub.class. Within the server directory, start the rmiregistry with the command "rmiregistry &" (Unix) or "start rmiregistry (DOS)". Run the server with the command "java CalculatorServer". 3. In the client directory, enter the following program: //******************************************************* // CalculatorClient.java // This client gets a remote reference from the rmiregistry // that is listening on the default port of 1099. // It allows the client to quit with a "!". // Otherwise, it computes the sum of two integers // using the remote calculator. import java.rmi.*; import java.rmi.server.*; import java.io.*; import java.util.StringTokenizer; public class CalculatorClient { public static void main(String args[]) throws Exception { BufferedReader in = new BufferedReader( new InputStreamReader(System.in)); // connect to the rmiregistry and get a remote reference to the Calculator // object. Calculator c = (Calculator) Naming.lookup("//localhost/CoolCalculator"); System.out.println("Found calculator. Enter ! to quit"); while(true) { try { // prompt the user System.out.print("client>"); // get a line String line = in.readLine(); // if a "!" is entered just exit if(line.equals("!")) System.exit(0); // if it's not a return get the two integers and call add // on the remote calculator. if(!line.equals("")) { StringTokenizer st = new StringTokenizer(line); String v1 = st.nextToken(); String v2 = st.nextToken(); int i = Integer.parseInt(v1); int j = Integer.parseInt(v2); int sum = c.add(i,j); System.out.println(sum); } } catch(RemoteException e) { System.out.println("allComments: " + e.getMessage()); } } } } Compile the code on the client and run with the command "java CalculatorClient". Study what you have and then begin the main exersise of this lab. =============================================================================== Part 2. ======= In this part, you will compare the performance of web services with Java RMI. Write a web service according to the following specification: @WebMethod(operationName = "bump") public boolean bump() { // A call on bump() adds 1 to a BigInteger held by the service. // It then returns true on completion. // The BigInteger is changed by the call on bump(). That is, // 1 is added to the BigInteger and that value persists until // another call on bump occurs. } @WebMethod(operationName = "get") public BigInteger get() { // a call on get returns the BigInteger held by the service } Write a web service client according to the following specification: The main routine creates a BigInteger (called ctr) initialized to 0. The main routine creates another BigInteger (called n) initialized to 10000. The main routine loops until the ctr equals n. Each time through the loop, ctr is incremented by 1. Each time through the loop, the web service method bump is called. Before the loop in the main routine begins, set a timer like this: long start = System.currentTimeMillis(); When the loop is finished, find the ending time like this: long stop = System.currentTimeMillis(); At the end of the main routine, display the value of the BigInteger held on the server by calling the get() method. In addition, display the number of seconds that it took to call this service 10,000 times. Write a Java RMI service according to the following specification: // The class extends UnicastRemoteObject and implements Bumper // The server calls rebind on the rmiregistry giving the remote // object the name "bumper". public boolean bump() throws RemoteException { // A call on bump() adds 1 to a BigInteger held by the service. // It then returns true on completion. // The BigInteger is changed by the call on bump(). That is, // 1 is added to the BigInteger and that value persists until // another call on bump occurs. } public BigInteger get() throws RemoteException { // a call on get returns the BigInteger held by the service } Write a Java RMI client according to the following specification: The main routine performs a lookup on the rmi registry for a remote object that implements the Bumber interface. The object is called "bumper". The main routine creates a BigInteger (called ctr) initialized to 0. The main routine creates another BigInteger (called n) initialized to 10000. The main routine loops until the ctr equals n. Each time through the loop, ctr is incremented by 1. Each time through the loop, the remote method bump is called. Before the loop in the main routine begins, set a timer like this: long start = System.currentTimeMillis(); When the loop is finished, find the ending time like this: long stop = System.currentTimeMillis(); At the end of the main routine, display the value of the BigInteger held on the server by calling the remote method get(). In addition, display the number of seconds that it took to call this service 10,000 times. What do you conclude? Which is faster, RMI or web service? And, by how much?