corejava第10版

corejava第10版/v2ch10/tableModel/InvestmentTable.java

@@ -0,0 +1,89 @@
+package tableModel;
+
+import java.awt.*;
+
+import javax.swing.*;
+import javax.swing.table.*;
+
+/**
+ * This program shows how to build a table from a table model.
+ * @version 1.03 2006-05-10
+ * @author Cay Horstmann
+ */
+public class InvestmentTable
+{
+   public static void main(String[] args)
+   {
+      EventQueue.invokeLater(() ->
+         {
+            JFrame frame = new InvestmentTableFrame();
+            frame.setTitle("InvestmentTable");               
+            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+            frame.setVisible(true);
+         });
+   }
+}
+
+/**
+ * This frame contains the investment table.
+ */
+class InvestmentTableFrame extends JFrame
+{
+   public InvestmentTableFrame()
+   {
+      TableModel model = new InvestmentTableModel(30, 5, 10);
+      JTable table = new JTable(model);
+      add(new JScrollPane(table));
+      pack();
+   }
+
+}
+
+/**
+ * This table model computes the cell entries each time they are requested. The table contents shows
+ * the growth of an investment for a number of years under different interest rates.
+ */
+class InvestmentTableModel extends AbstractTableModel
+{
+   private static double INITIAL_BALANCE = 100000.0;
+   
+   private int years;
+   private int minRate;
+   private int maxRate;
+
+   /**
+    * Constructs an investment table model.
+    * @param y the number of years
+    * @param r1 the lowest interest rate to tabulate
+    * @param r2 the highest interest rate to tabulate
+    */
+   public InvestmentTableModel(int y, int r1, int r2)
+   {
+      years = y;
+      minRate = r1;
+      maxRate = r2;
+   }
+
+   public int getRowCount()
+   {
+      return years;
+   }
+
+   public int getColumnCount()
+   {
+      return maxRate - minRate + 1;
+   }
+
+   public Object getValueAt(int r, int c)
+   {
+      double rate = (c + minRate) / 100.0;
+      int nperiods = r;
+      double futureBalance = INITIAL_BALANCE * Math.pow(1 + rate, nperiods);
+      return String.format("%.2f", futureBalance);
+   }
+
+   public String getColumnName(int c)
+   {
+      return (c + minRate) + "%";
+   }
+}