invoicer.java

Java程序设计技巧与开发实例附书源代码。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;

public class Invoicer
    extends JFrame {
  public NoEditTableModel data = new NoEditTableModel();
  public JTable table = new JTable(data);
  public JLabel price = new JLabel("￥0.0", SwingConstants.RIGHT);

  private class WindowCloser
      extends WindowAdapter {
    public void windowClosing(WindowEvent we) {
      System.exit(0);
    }
  }

  public Invoicer() {
    super("Simple Table");
    createDataColumns();
    createSampleData();
    JScrollPane scrollTable = new JScrollPane(table);
    price.setText("Total Price: ￥" + total());
    scrollTable.setPreferredSize(new Dimension(400, 100));

    getContentPane().add("Center", new JPanelBox(scrollTable, "Data"));
    getContentPane().add("South", new JPanelBox(price, "Total Cost"));
    addWindowListener(new WindowCloser());
    table.addMouseListener(new InvoicePopup(this));
    table.setToolTipText("Right-Click for menu");

    validate();
    pack();
    setVisible(true);
  }

  private void createDataColumns() {
    /* create columns with appropriate headers */
    data.addColumn("ID");
    data.addColumn("Description");
    data.addColumn("Unit Price");
    data.addColumn("Quantity");
    data.addColumn("Price");
  }

  private void createSampleData() {
    /* create some sample data */
    data.addRow(dataRow(19, "IBM 770 Laptop", 26800, 1));
    data.addRow(dataRow(207, "External ZIP drive", 580, 1));
    data.addRow(dataRow(1008, "SDRAM Memory Chips, 128MB", 150, 4));
    data.addRow(dataRow(44, "IBM 21' Triniton Monitor", 3880, 1));
    data.addRow(dataRow(105, "External Keyboard, black", 480, 1));
    data.addRow(dataRow(207, "External Mouse, black", 160, 1));
    data.addRow(dataRow(45, "IBM Port Replicator", 1200, 1));
  }

  private Object[] dataRow(int id, String desc, double price, int num) {
    /* utility method to convert basic types into array of Objects */
    Object row[] = new Object[5];
    row[0] = new Integer(id);
    row[1] = desc;
    row[2] = new Double(price);
    row[3] = new Integer(num);
    row[4] = new Double(price * num);
    return row;
  }

  protected double total() {
    /* computes the total in the last column of the table */
    double sum = 0.0;
    for (int row = 0; row < data.getRowCount(); row++) {
      sum += ( (Double) data.getValueAt(row, 4)).doubleValue();
    }
    return sum;
  }

  public static void main(String args[]) {
    Invoicer st = new Invoicer();
  }
}