tablechart.java

java swing 开发代码

// TableChart.java
// A chart-generating class that uses the TableModel interface to get
// its data.
//
package	jswing.ch16;

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

public class TableChart extends JComponent implements TableModelListener {

  protected TableModel model;
  protected ChartPainter cp;
  protected double[] percentages;  // pie slices
  protected String[] labels;       // labels for slices
  protected String[] tips;         // tooltips for slices

  protected java.text.NumberFormat formatter = 
                java.text.NumberFormat.getPercentInstance();

  public TableChart(TableModel tm) {
    setUI(cp = new PieChartPainter());
    setModel(tm);
  }

  public void setTextFont(Font f) { cp.setTextFont(f); }
  public Font getTextFont() { return cp.getTextFont(); }

  public void setTextColor(Color c) { cp.setTextColor(c); }
  public Color getTextColor() { return cp.getTextColor(); }

  public void setColor(Color[] clist) { cp.setColor(clist); }
  public Color[] getColor() { return cp.getColor(); }

  public void setColor(int index, Color c) { cp.setColor(index, c); }
  public Color getColor(int index) { return cp.getColor(index); }

  public String getToolTipText(MouseEvent me) {
    if (tips != null) {
      int whichTip = cp.indexOfEntryAt(me);
      if (whichTip != -1) {
        return tips[whichTip];
      }
    }
    return null;
  }

  public void tableChanged(TableModelEvent tme) {
    // Rebuild the arrays only if the structure changed.
    updateLocalValues(tme.getType() != TableModelEvent.UPDATE);
  }

  public void setModel(TableModel tm) {
    // get listener code correct.
    if (tm != model) {
      if (model != null) {
        model.removeTableModelListener(this);
      }
      model = tm;
      model.addTableModelListener(this);
      updateLocalValues(true);
    }
  }

  public TableModel getModel() { return model; }

  // Run through the model and count every cell (except the very first column,
  // which we assume is the slice label column).
  protected void calculatePercentages() {
    double runningTotal = 0.0;
    for (int i = model.getRowCount() - 1; i >= 0; i--) {
      percentages[i] = 0.0;
      for (int j = model.getColumnCount() - 1; j >=0; j--) {
        
        // First try the cell as a Number object.
        Object val = model.getValueAt(i,j);
        if (val instanceof Number) {
          percentages[i] += ((Number)val).doubleValue();
        }
        else if (val instanceof String) { 
          // oops, it wasn't numeric...
          // Ok, so try it as a string
          try {
            percentages[i]+=Double.valueOf(val.toString()).doubleValue();
          } 
          catch(Exception e) {
            // not a numeric string...give up.
          } 
        }
      }
      runningTotal += percentages[i];
    }

    // Make each entry a percentage of the total.
    for (int i = model.getRowCount() - 1; i >= 0; i--) {
      percentages[i] /= runningTotal;
    }
  }

  // This method just takes the percentages and formats them for use as
  // tooltips.
  protected void createLabelsAndTips() {
    for (int i = model.getRowCount() - 1; i >= 0; i--) {
      labels[i] = (String)model.getValueAt(i, 0);
      tips[i] = formatter.format(percentages[i]);
    }
  }

  // Call this method to update the chart.  We try to be a bit efficient here
  // in that we allocate new storage arrays only if the new table has a
  // different number of rows.
  protected void updateLocalValues(boolean freshStart) {
    if (freshStart) {
      int count = model.getRowCount();
      if ((tips == null) || (count != tips.length)) {
        percentages = new double[count];
        labels = new String[count];
        tips = new String[count];
      }
    }
    calculatePercentages();
    createLabelsAndTips();

    // Now that everything's up-to-date, reset the chart painter with the new
    // values.
    cp.setValues(percentages);
    cp.setLabels(labels);

    // Finally, repaint the chart.
    repaint();
  }
}