Javaサンプル(棒グラフをドラッグして値変更)

//Sample16
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class Sample16 extends JFrame implements MouseListener,
    MouseMotionListener {
  private static final long serialVersionUID = -5235421690704702101L;
  private static final int origin_X = 300;
  private static final int origin_Y = 300;
  private static final int rect_pitch = 40;
  private static final int rect_width = 10;
  private static final String tf_init_value = "100";
  private static final int tf_size = 3;
  private static final int eps = 3;
  private static final String window_title = "棒グラフをドラッグして値変更";
  private static final int window_width = 640;
  private static final int window_height = 400;
  JTextField[] tf = new JTextField[2];
  static double x1 = 303;
  static double y1 = 198;
  static double x2 = 343;
  static double y2 = 198;
  static int sw = 0;
  // 主処理
  public static void main(final String ar[]) {
    final JFrame f = new Sample16();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setSize(Sample16.window_width, Sample16.window_height);
    f.setVisible(true);
  }
  // 部品セット
  Sample16() {
    super(Sample16.window_title);
    final Container c = this.getContentPane();
    final JPanel p1 = new JPanel();
    for (int i = 0; i < this.tf.length; i++) {
      this.tf[i] = new JTextField(Sample16.tf_init_value,
          Sample16.tf_size);
      p1.add(this.tf[i]);
    }
    c.add(p1, BorderLayout.NORTH);
    this.addMouseListener(this);
    this.addMouseMotionListener(this);
  }
  // 描画
  @Override
  public void paint(final Graphics g) {
    final double r = 2;
    final Graphics2D g2 = (Graphics2D) g;
    g
        .clearRect(0, 0, Sample16.window_width - 1,
            Sample16.window_height - 1);
    for (int i = 0; i < this.tf.length; i++) {
      this.tf[i].repaint();
      final String rs = this.tf[i].getText();
      if (rs != null) {
        try {
          final double rect_height = Double.parseDouble(rs);
          g2.setPaint(Color.blue);
          g2.fill(new Rectangle2D.Double(Sample16.origin_X + i
              * Sample16.rect_pitch, Sample16.origin_Y
              - rect_height, Sample16.rect_width, rect_height));
          g2.setPaint(Color.red);
          g2.fill(new Ellipse2D.Double(Sample16.origin_X + 5 + i
              * Sample16.rect_pitch - r, Sample16.origin_Y
              - rect_height - r, 2 * r, 2 * r));
          if (i == 0) {
            Sample16.y1 = Sample16.origin_Y - rect_height - r;
          }
          if (i == 1) {
            Sample16.y2 = Sample16.origin_Y - rect_height - r;
          }
        } catch (final NumberFormatException e) {
        }
      }
    }
  }
  // マウスイベント
  public void mousePressed(final MouseEvent me) {
    Sample16.sw = 0;
    final double x = me.getX();
    final double y = me.getY();
    if ((Math.abs(Sample16.x1 - x) < Sample16.eps)
        && (Math.abs(Sample16.y1 - y) < Sample16.eps)) {
      Sample16.sw = 1;
    }
    if ((Math.abs(Sample16.x2 - x) < Sample16.eps)
        && (Math.abs(Sample16.y2 - y) < Sample16.eps)) {
      Sample16.sw = 2;
    }
  }
  // マウスドラッグイベント
  public void mouseDragged(final MouseEvent me) {
    if (Sample16.sw > 0) {
      final int y = me.getY();
      this.tf[Sample16.sw - 1].setText("" + (Sample16.origin_Y - 2 - y));
      this.repaint();
    }
  }
  public void mouseReleased(final MouseEvent me) {
  }
  public void mouseMoved(final MouseEvent me) {
  }
  public void mouseEntered(final MouseEvent me) {
  }
  public void mouseExited(final MouseEvent me) {
  }
  public void mouseClicked(final MouseEvent me) {
  }
}