filemodel.java

实现网格环境下资源调度和分配的仿真

/*
 * Title:        Visual Modeler for GridSim Toolkit
 * Description:  This Visual Modeler enables the user to quickly create
 *               experiments on different Grid testbeds and generate the
 *               default Grid Broker source codes (in Java).
 *
 * $Id: FileModel.java,v 1.6 2003/06/19 07:31:00 anthony Exp $
 */

package visualmodeler;

import java.awt.Toolkit;
import java.util.*;
import java.io.*;
import javax.swing.*;

// to handle loading XML. These packages exist since java 1.4
import org.w3c.dom.*;
import javax.xml.parsers.*;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;


/**
 * FileModel deals with the back-end operation of the VisualModeler system.
 * The operations handle by this class are:
 * <ul>
 * <li> saving new file in XML format
 * <li> opening new file in XML format
 * <li> generating Java code to be used in GridSim simulation
 * </ul>
 *
 * @author       Anthony Sulistio and Chee Shin Yeo
 * @version      1.1
 * @invariant $none
 */
public class FileModel extends Observable
{
    private DefaultFileFilter fileFilter_;
    private JFrame frame_;
    private UserModel user_;
    private ResourceModel res_;
    private final JFileChooser fc_;

    private boolean hasSaved_;
    private JOptionPane optionPane_;
    private String fileName_;
    private Toolkit toolkit_;


    /**
     * Allocates a new FileModel object
     * @param frame  a JFrame object
     * @param user   a UserModel object
     * @param res    a ResourceModel object
     * @pre frame != null
     * @pre user != null
     * @pre res != null
     * @post $none
     */
    public FileModel(JFrame frame, UserModel user, ResourceModel res)
    {
        frame_ = frame;
        user_ = user;
        res_ = res;

        fileName_ = null;
        hasSaved_ = false;

        toolkit_ = Toolkit.getDefaultToolkit();
        fc_ = new JFileChooser();
        fileFilter_ = new DefaultFileFilter("xml", "XML Files");

        optionPane_ = new JOptionPane("Empty message",
                                JOptionPane.QUESTION_MESSAGE,
                                JOptionPane.YES_NO_OPTION);
    }

    /**
     * Saves the Visual Modeler project file 
     * @pre $none
     * @post $none
     */
    public void saveFile()
    {
        // if no changes to both user and resource model, then exit
        if (user_.hasChanged() == false && res_.hasChanged() == false) {
            return;
        }

        if (fileName_ != null)
        {
            save();
            return;
        }

        fc_.setDialogTitle("Save");
        fc_.setFileFilter(fileFilter_);

        int returnVal = fc_.showSaveDialog(frame_);
        if (returnVal == JFileChooser.APPROVE_OPTION) {
            displaySaveDialog();
        }
    }

    /**
     * A method that asks the user to save the changes before exiting the
     * program 
     * @pre $none
     * @post $none
     */
    public void newFile()
    {
        // if the file has been saved before then open a new file and
        // reset the flag
        if (hasSaved_ == true)
        {
            hasSaved_ = false;
            user_.newValue();
            res_.newValue();
            fileName_ = null;
            return;
        }

        // if no changes to both user and resource model, then exit
        if (user_.hasChanged() == false && res_.hasChanged() == false) {
            return;
        }

        String msg="This file has not been saved yet.\nOpen a new file anyway?";
        if (confirmAction(msg, "New File") == true)
        {
            user_.newValue();
            res_.newValue();
            hasSaved_ = false;
            fileName_ = null;
        }
    }

    /**
     * A method that handles the dialog to open a new file 
     * @pre $none
     * @post $none
     */
    public void openFile()
    {
        // if no changes to both user and resource model, then open
        if (user_.hasChanged() == false && res_.hasChanged() == false)
        {
            displayOpenDialog();
            return;
        }

        String msg="This file has not been saved yet.\nOpen a new file anyway?";
        if (confirmAction(msg, "Open File") == true) {
            displayOpenDialog();
        }
    }

    /**
     * A method that shows a close file dialog 
     * @pre $none
     * @post $none
     */
    public void closeFile()
    {
        // if no changes to both user and resource model, then exit
        if (user_.hasChanged() == false && res_.hasChanged() == false) {
            return;
        }

        String msg = "The file has not been saved yet.\nClose anyway?";
        if (confirmAction(msg, "Close File") == true)
        {
            user_.newValue();
            res_.newValue();
            fileName_ = null;
        }
    }

    /**
     * A method that shows a Save As dialog 
     * @pre $none
     * @post $none
     */
    public void saveAsFile()
    {
        fc_.setDialogTitle("Save As");
        fc_.setFileFilter(fileFilter_);

        int returnVal = fc_.showSaveDialog(frame_);
        if (returnVal == JFileChooser.APPROVE_OPTION) {
            displaySaveDialog();
        }
    }

    /**
     * A method that asks the user whether to quit the program or not
     * @return <tt>true</tt> if the user wants to quit, <tt>false</tt> otherwise
     * @pre $none
     * @post $none
     */
    public boolean quitProgram()
    {
        // if no changes to both user and resource model, then exit
        if (user_.hasChanged() == false && res_.hasChanged() == false) {
            return true;
        }

        String msg = "The file has not been saved yet.\nQuit anyway?";
        if (confirmAction(msg, "Exit Program") == true)
        {
            user_.newValue();
            res_.newValue();

            return true;
        }

        return false;
    }

    /**
     * Generates a Java source code 
     * @pre $none
     * @post $none
     */
    public void generateCode()
    {
        // if no changes to both user and resource model, then exit
        /******
        if (user_.hasChanged() == false && res_.hasChanged() == false)
        {
            toolkit_.beep();
            JOptionPane.showMessageDialog(frame_,
                "Cannot generate GridSim code.\n" +
                "No user or resource has been created.",
                "Generate GridSim code",
                JOptionPane.ERROR_MESSAGE);

            return;
        }
        *************/

        DefaultFileFilter filter = new DefaultFileFilter("java", "Java Files");

        fc_.setDialogTitle("Generate GridSim code");
        fc_.setFileFilter(filter);

        int returnVal = fc_.showSaveDialog(frame_);
        if (returnVal != JFileChooser.APPROVE_OPTION) {
            return;
        }

        // get the name of the file and use it as a java class name
        File file = fc_.getSelectedFile();
        String className = file.getName();
        className = fileFilter_.getFileNameOnly(className);

        // Creates a string buffer with long chars to increase performance
        StringBuffer buffer = new StringBuffer(1000); 
        
        // this will get the absolute directory path + file name
        buffer.append( file.getAbsolutePath() );

        // if the filename has no extension, then attach
        if (fileFilter_.getExtension(file) == null) {
            buffer.append(".java");
        }

        // Copy the file name
        String name = buffer.toString();

        // if a file already exists, then double check with user
        File newFile = new File(name);
        if (newFile.exists() == true)
        {
            // reset the buffer
            buffer.delete( 0, buffer.length() );
            buffer.append(name);
            buffer.append(" already exists.\nDo you want to replace it?");
            
            if ( confirmAction(buffer.toString(), "Generate GridSim code") 
                    == false ) 
            {
                return;
            }
        }

        String indent = "    ";     // 4 spaces
        
        // reset the buffer
        buffer.delete( 0, buffer.length() );

        // Writes the Java file header
        buffer.append("// This file is auto-generated by VisualModeler.\n");
        buffer.append("// Created on ");

        Date date = Calendar.getInstance().getTime();
        buffer.append( date.toString() );
        buffer.append("\n\n");
        buffer.append("import java.util.*;\n");
        buffer.append("import gridsim.*;\n");
        buffer.append("import gridbroker.*;\n");

        // writes the class name and static method
        buffer.append("\npublic class ");
        buffer.append(className);
        buffer.append(" \n{\n\n");
        buffer.append(indent);
        buffer.append("public static void main(String[] args)\n");
        buffer.append(indent);
        buffer.append("{\n\n");

        // writes statements inside the main method