stocktable.java

一个关于SWING学习的源代码. 大家过来看一看

package com.pepsan.framework;

/*
 *  A table of stocks and quotes. The stocks in the table are fixed.
 *  The quotes are retreived dynamically over the Internet from Yahoo's site.
 *
 *	The length of the table is not fixed.
 *
 *	Copyright (c) 1999 Pepsan & Associates, Inc.
 */

import javax.swing.*;
import javax.swing.table.*;
import javax.swing.border.*;

import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Color;
import java.net.*;
import java.awt.event.*;
import java.io.*;

public class StockTable extends JFrame {
	final TableModel dataModel;
	// These two strings are Yahoo magic. They could change, by Yahoo, at any
	// time and break this little bit of code.
	final String quotePrefix = "http://quote.yahoo.com/d/quotes.csv?s=";
	final String quoteSuffix = "&f=sl1d1t1c1ohgv&e=.csv";
    final JFrame	frame = this;
    
    public StockTable() {
    	super("Stock Quotes"); 	
	
        // Headings for table
        final String[] names = {"Company", "Symbol", "Current Price",
                                "Own?"};
        // List of stocks
        final Object[][] data = {
	    {"Apple", "AAPL", new Float(0.0), new Boolean(true)},
	    {"Cisco", "CSCO", new Float(0.0), new Boolean(false)},
	    {"CNET", "CNET", new Float(0.0), new Boolean(true)},
	    {"MCI Worldcom", "WCOM", new Float(0.0), new Boolean(true)},
	    {"Adaptec", "ADPT", new Float(0.0), new Boolean(false)},
        };
        
        // Handle window closing
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
            	frame.setVisible(false);
            }
        });
            
        // A simple table model
        dataModel = new AbstractTableModel() {
            // These methods always need to be implemented.
            public int getColumnCount() { return names.length; }
            public int getRowCount() { return data.length;}
            public Object getValueAt(int row, int col) {return data[row][col];}
            public String getColumnName(int column) {return names[column];}
            public Class getColumnClass(int col) {
            	return getValueAt(0,col).getClass();
            }
            public boolean isCellEditable(int row, int col) {return false;}
            public void setValueAt(Object aValue, int row, int column) {
                data[row][column] = aValue;
                fireTableCellUpdated(row, column);
            }
         };

        // Whoppee. The table sorts!
        TableSorter  sorter = new TableSorter(dataModel);
        JTable    tableView = new JTable(sorter);
        sorter.addMouseListenerToHeaderInTable(tableView);

		// Of course we want a scrolling table
        JScrollPane scrollpane = new JScrollPane(tableView);
		scrollpane.setPreferredSize(new Dimension(400, 150));
	
		// Clicking this button causes a background update in a Swing worker object
    	JButton	updateButton = new JButton("Update Prices");
    	updateButton.setBackground(Color.green);
    	
    	// The update button kicks of a Swing worker object to run the update
    	// This allows the rest of the application to keep running while we fetch the data
    	// It is here to remind people that Swing is not thread safe...
    	// See <http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html> for more info.
    	//
    	// We show a progress bar to prove we're doing something
    	updateButton.addActionListener(new ActionListener() {
    		public void actionPerformed(ActionEvent e) {
    			final SwingWorker worker = new SwingWorker() {
			        public Object construct() {
				        JProgressBar pBar = new JProgressBar(0, data.length);
				        pBar.setStringPainted(true);
				        JLabel quoteLabel = new JLabel((String) dataModel.getValueAt(0,0), SwingConstants.CENTER);

						// This dialog is not modal
				        JDialog pDialog = new JDialog(frame, "Getting Initial Quotes", false);
				        pDialog.getContentPane().add(pBar, BorderLayout.CENTER);
						pDialog.getContentPane().add(quoteLabel, BorderLayout.SOUTH);
						pDialog.pack();
				        pDialog.show();
				        // For each stock in the table, fetch a quote
				        // The quote should be the second field, comma separated. Of course Yahoo could change
				        // this at any time
				        for (int i=0; i<data.length; i++) {
				        	dataModel.setValueAt(getQuote(quotePrefix + dataModel.getValueAt(i,1) + quoteSuffix), i, 2);
				        	quoteLabel.setText((String) dataModel.getValueAt(i,0));
				        	pBar.setValue(i+1);
				        }
			        	pDialog.dispose();
				        return "";	// We have to return an Object, doesn't matter what
			        }
			        public void finished() {
			        	// Actually nothing to do here, but we could do something!!! :-)
			        }
				};
	   		}
	   	});
        
        frame.getContentPane().add(scrollpane, BorderLayout.CENTER);
        frame.getContentPane().add(updateButton, BorderLayout.SOUTH);
        frame.pack();
        frame.setVisible(true);

        // Get stock quotes now (this is blocking, unlike the update button)
        // This is a funky way to show a bunch of text in a dialog
        Object[] diabolical = new Object[] {
        	"This fetches quotes in the main thread and so blocks all other activity.",
        	"Hit OK to continue.",
        	"Cancel not allowed :-)",
        	"Yes it's diabolical! Muhahahaha!!!",
        	"But it illustrates threading...",
        	"The Update button updates in a SwingWorker thread.",
        	"It's available to update quotes once this finishes.",
        	"Try it and see!",
        	"For now, just hit OK and wait for the completion dialog to appear"};
        JOptionPane startPane = new JOptionPane(diabolical, JOptionPane.INFORMATION_MESSAGE);
        JDialog startDialog = startPane.createDialog(frame, "Gettings Quotes");
        // This will block until the user hits OK
        startDialog.show();
        
        // For each stock in the table, fetch a quote
        // The quote should be the second field, comma separated. Of course Yahoo could change
        // this at any time
        for (int i=0; i<data.length; i++) {
        	dataModel.setValueAt(getQuote(quotePrefix + dataModel.getValueAt(i,1) + quoteSuffix), i, 2);
        }
        JOptionPane donePane = new JOptionPane("Initial quotes received! Hit Update to stay current.", JOptionPane.INFORMATION_MESSAGE);
        JDialog doneDialog = donePane.createDialog(frame, "Got Quotes");
        doneDialog.show();
    }
    
    // Use the URL class to grab the quote from Yahoo
    // The quote should be comma separated with the price the second field
    // This is a *really* ugly way to parse the return string :( Don't do it this way!
    private Float getQuote(String quoteString) {
        int			curByte;
        char		curChar;
        String		curQuote;
        boolean		priceFlag;
        
        try {
	        URL quoteURL = new URL(quoteString);
	        try {
	        	DataInputStream quoteStream = new DataInputStream(quoteURL.openStream());
	        	priceFlag = false;
	        	curQuote = "";
	        	while( (curByte = quoteStream.read()) != -1) {
	        		curChar = (char) curByte;
	        		if (!priceFlag && (curChar == ',')) {
	        			priceFlag = true;
	        			continue;
	        		}
	        		if (priceFlag) {
	        			if (curChar == ',') {
	        				break;
	        			} else {
	        				curQuote += curChar;
	        			}
	        		}
	        	}
	        	return new Float(curQuote);
			} catch (IOException e) {
				System.err.println("getContent on quote failed: " + e);
			}
		} catch (MalformedURLException e) {
			System.err.println("Yikes. URL exception");
		}    
	// Return a -1.0 if the fetch failed
	return new Float(-1.0);
    }
}