import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.imageio.*;
import java.io.*;

/**
 * This program illustrates the display of an image stored in
 * a database as a Blob.
**/

public class Blobber implements ActionListener {
    private JFrame frame;
    private JPanel inputPanel;
    private Canvas imageCanvas;
    private JComboBox nameBox;
    private Image image;
    private DatabaseAccess dlink;

    public Blobber(DatabaseAccess dlink) {
      this.dlink = dlink;

	// Set up the frame
	frame = new JFrame("Blob Test");
	frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

	// Set up the input panel
	inputPanel = new JPanel(new FlowLayout());
	inputPanel.setBackground(Color.LIGHT_GRAY);

      // Add the combo box to the input panel
      nameBox = new JComboBox(dlink.getCarList().toArray());
      nameBox.setSelectedIndex(0);
      nameBox.addActionListener(this);
      inputPanel.add(nameBox);

      // Put the input panel in the frame
      frame.getContentPane().add(inputPanel, BorderLayout.SOUTH);

      // Create the image canvas and put it in the frame
      imageCanvas = new Canvas(){
	      public void paint(Graphics g){
		  g.drawImage(image,0,0,null);
	      }
	  };
      imageCanvas.setSize(500,500);

      frame.getContentPane().add(imageCanvas, BorderLayout.CENTER);

      frame.pack();

      // Display the frame
      frame.setVisible(true);
    }

    /* Listener method to handle events */
    public void actionPerformed(ActionEvent e) {
	if (e.getSource() == nameBox) { // event came from the combo box
	    String name = (String) nameBox.getSelectedItem();
	    getImage(name);
          imageCanvas.repaint();
      }
    }

    /* retrieve the car's picture and display it */
    private void getImage(String name) {
       InputStream imageStream = dlink.getImageStream(name);
       try {
          image = ImageIO.read(imageStream);
	  int w = image.getWidth(frame);
	  int h = image.getHeight(frame);
	  imageCanvas.setSize(w,h);
	  frame.pack();
       }
       catch (IOException e){
         warnUser(e.getMessage());
       }
    }

    /**
     * Display a pop-up window to the user
     */
    private void warnUser(String message) {
	JOptionPane.showMessageDialog(frame, message, "Error",
		JOptionPane.WARNING_MESSAGE);
    }

    public static void main(String [] args) {
	Blobber x = new Blobber(new DatabaseAccess());
    }
}