client.java

EJB_原代码多例-好好东西啊

package com.wiley.compBooks.roman.session.fazuul;

import javax.ejb.*;
import javax.naming.*;
import java.rmi.*;
import java.util.*;
import java.io.*;

/**
 * Client for Fazuul Game.
 */
public class Client {

	public static void main(String[] args) {

		new Client().start();
	}

	// Current list of Component EJB Objects I own
	private Vector components = new Vector();

	// A Machine which dispenses Component EJB Objects
	private Machine machine;

	/**
	 * Starts the game.  The main game loop is here.
	 */
	public void start() {

		try {
			/*
			 * Get System properties for JNDI initialization
			 */
			Properties props = System.getProperties();

			/*
			 * Get a reference to the MachineHome Object - the
			 * factory for Machine EJB Objects
			 */
			Context ctx = new InitialContext(props);
			MachineHome home = (MachineHome) ctx.lookup("MachineHome");

			/*
			 * Use the factory to create the Machine EJB Object 
			 */
			machine = home.create();
		}
		catch (Exception e) {
			e.printStackTrace();
			System.exit(-1);
		}

		/*
		 * Start reading input from standard input
		 */	
		String line = null, command = null, args = null;
		StringTokenizer tokens = null;
                BufferedReader reader = new BufferedReader(new InputStreamReader (System.in));

                while (true) {

			/*
			 * Print prompt, read next input line, and get command
			 */
			try {
				System.out.println();
				System.out.print("> ");
                        	line = reader.readLine();
				System.out.println();
                        	tokens = new StringTokenizer(line, " ", false);
                       		// Get command.  e.g. "attach" or "inv" 
				command = tokens.nextToken();

				// Get arguments to command.
				args = null;
				if (tokens.hasMoreElements()) {
					args = line.substring(command.length()+1, line.length());
				}
			}
			catch (Exception e) {
				continue;
			}
		
			/*
			 * Do case analysis based upon command.
			 */
			try {
				/*
				 * If the user wants to examine a component
				 */
				if (command.equals("examine")) {
					examine(args);
				}

				/*
				 * If user wants to attach 2 components,
				 * then extract the 2 component names from
				 * the argument string, and call attach()
				 */
				else if (command.equals("attach")) {
					String item1 = null, item2 = null;
					try {
						StringTokenizer argtokens = new StringTokenizer(args, " ");
						item1 = argtokens.nextToken();
						argtokens.nextToken();
						item2 = argtokens.nextToken();
					}
					catch (Exception e) {
						throw new Exception("Syntax: attach <item1> to <item2>");
					}

					attach(item1, item2);
				}
				/*
				 * If the user wants to discard an object
				 */
				else if (command.equals("drop")) {
					drop(args);
				}
				/*
				 * If the user needs more components
				 */
				else if (command.equals("gimme")) {
					gimme();
				}
				/*
				 * If the user wants to list the components
				 * he has.
				 */
				else if (command.equals("inv")) {
					inv();
				}
				/*
				 * If the user wants to end the game
				 */
				else if (command.equals("quit")) {
					quit();
				}
				/*
				 * If the user wants to suspend the game
				 */
				else if (command.equals("suspend")) {
					if (args == null) {
						System.out.println("Please specify a filename.");
					}
					else {
						suspend(args);
					}
				}
				/*
				 * If the user wants to resume a suspended
				 * game.
				 */
				else if (command.equals("resume")) {
					if (args == null) {
						System.out.println("Please specify a filename.");
					}
					else {
						resume(args);
					}
				}


				else {
					System.out.println("Syntax: [attach <item1> to <item2> | examine <item> | inv | gimme | drop <item> | suspend <filename> | resume <filename> | quit]");
				}
			}
			catch (Exception e) {
				e.printStackTrace();
			}
		}
	}

	/**
	 * Suspends the game.  Writes the current game state to disk
	 * via EJB object handles.
	 */
	private void suspend(String filename) {

		ObjectOutputStream stream = null;

		try {
			stream = new ObjectOutputStream(
				new FileOutputStream(filename));

			for (int i=0; i < components.size(); i++) {
				Component comp = (Component) components.elementAt(i);
				Handle handle = comp.getHandle();
				stream.writeObject(handle);
			}

			stream.flush();
		
			System.out.println("Game saved.");
		}
		catch (Exception e) {
			e.printStackTrace();
		}
		finally {
			if (stream != null) {
				try { stream.close(); } catch (Exception e) {}
			}
		}

		System.exit(0);
	}


	/**
	 * Resumes a suspended game via EJB object handles. 
	 */
	private void resume(String filename) {
	
		clearComps();

		ObjectInputStream stream = null;

		try {
			stream = new ObjectInputStream(
				new FileInputStream(filename));

			while (true) {
				Handle handle = (Handle) stream.readObject();
				
				components.addElement(
					(Component) handle.getEJBObject());
			}
		}
		catch (EOFException e) {
			System.out.println("Game loaded.");
		}
		catch (Exception e) {
			e.printStackTrace();
		}
		finally {
			if (stream != null) {
				try { stream.close(); } catch (Exception e) {}
			}
		}
	}

	/*
	 * Removes all components the user has.
	 */
	private void clearComps() {

		System.out.println("Clearing game state...");

		for (int i=0; i < components.size(); i++) {
			try {
				Component comp =
					(Component) components.elementAt(i);

				comp.remove();
			}
			catch (Exception e) {
				e.printStackTrace();
			}
		}

		components = new Vector();
	}

	/**
	 * Quits the game, cleaning up all EJB Objects.
	 */
	private void quit() {

		/*
		 * 1: Remove all components
		 */
		clearComps();

		/*
		 * 2: Remove machine
		 */
		try {
			machine.remove();
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		System.exit(0);
	}

	/**
	 * Gets more components from the machine
	 */
	private void gimme() throws Exception {
		for (int i=0; i < 3; i++) {
			Component comp = machine.makeComponent();
			components.addElement(comp);
			System.out.println("The machine pops out a " + comp.getName());
		}
	}

	/**
	 * Drops a component.
	 */
	private void drop(String componentName) throws Exception {
		for (int i=0; i < components.size(); i++) {
			Component comp = (Component) components.elementAt(i);
			if (comp.getName().equals(componentName)) {
				// Call remove() on EJB Object
				comp.remove();

				components.removeElement(comp);
				System.out.println("You dropped your " + componentName);
				return;
			}
		}
	}

	/**
	 * Lists the inventory of components I currently have.
	 */
	private void inv() throws Exception {
		for (int i=0; i < components.size(); i++) {
			Component comp = (Component) components.elementAt(i);
			System.out.println(comp.getName());
		}
	}

	/**
	 * Prints out the description of component with name componentName.
	 */
	private void examine(String componentName) throws Exception {
		/*
		 * Loop through all the components.  Get the names of each
		 * component.  If the name matches, then print out that
		 * component's description.
		 */
		for (int i=0; i < components.size(); i++) {
			Component comp = (Component) components.elementAt(i);
			if (comp.getName().equals(componentName)) {
				System.out.println(comp.getDescription());
				return;
			}
		}	
	}

	/**
	 * Attempts to attach components with names A and B together.
	 */
	private void attach(String componentNameA, String componentNameB) throws Exception {
		Component componentA = null, componentB = null;

		/*
		 * Loop through all the components.  Get the Names of each
		 * component.  If the name matches, then that's our Component A.
		 */
		for (int i=0; i < components.size(); i++) {
			Component comp = (Component) components.elementAt(i);
			if (comp.getName().equals(componentNameA)) {
				componentA = comp;
			}
		}
	
		/*
		 * Print out some error codes if we didn't find any matches
		 */
		if (componentA == null) {
			System.out.println("You don't have a " + componentNameA);
			return;
		}
	
		/*
		 * Loop through all the components.  Get the Names of each
		 * component.  If the name matches, AND it's not the same
		 * as the Component A above, then that's our Component B.
		 */
		for (int i=0; i < components.size(); i++) {
			Component comp = (Component) components.elementAt(i);
			if (comp.getName().equals(componentNameB)
				&& (!comp.equals(componentA))) {
				componentB = comp;
			}
		}

		/*
		 * Print out some error codes if we didn't find any matches
		 */
		if (componentB == null) {
			System.out.println("You don't have a " + componentNameB);
			return;
		}

		/*
		 * Try to attach the two components.  If they attach,
		 * 1) Remove the old Component EJB Objects
		 * 2) Remove the old Components from our list of components
		 * 3) Add the new, combined component to our list
		 */
		try {
			Component newComp = componentA.attachTo(componentB);

			// Remove the two old Components' EJB Object
			componentA.remove();
			componentB.remove();

			components.removeElement(componentA);
			components.removeElement(componentB);
			components.addElement(newComp);

			System.out.println("Fitting the " + componentNameA + " into the " + componentNameB + ", out pops a " + newComp.getName() + "!");
		}
		/*
		 * If an application-level exception occurs (i.e. if
		 * the two components won't attach) then handle it.
		 * Let the main loop handle system-level exceptions.
		 */
		catch (ComponentException e) {
			System.out.println(e.toString());
		}
	}
}