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

/**
 * ChooseStringDialog
 * <br>
 * This class models a modal dialog box that allows a user to choose
 * one or more items (all strings) from a list displayed to him/her
 *
 * @version 0.1 alpha
 *
 * @author
 * This software was produced by NIST, an agency of the U.S. government, 
 * and by statute is not subject to copyright in the United States.  
 * Recipients of this software assume all responsibilities associated with 
 * its operation, modification and maintenance.
 */
public class ChooseStringDialog extends JDialog {
  private static ChooseStringDialog dialog;
  private static String[] values = null;
  private JList list;


  /**
   * Does intialization for a new dialog box
   *
   * @param com the parent component
   * @param choices array of strings user will choose from
   * @param title title of dialog box
   * @param labelText subtitle over the list of choices
   * @param selectionalModel - only one choice or multiple allowed
   */
  public static void initialize(Component comp,
				String[] choices,
				String title,
				String labelText,
				int selectionModel) {
    Frame frame = JOptionPane.getFrameForComponent(comp);
    dialog = new ChooseStringDialog(frame, choices,
			    title, labelText, selectionModel);
  }


  /**
   * Shows the dialog box and returns user's choice(s)
   *
   * @param comp component over which the dialog will appear
   * @param initialValue a choice to highlight when dialog first appears
   * @return an array with the choice(s) the user made
   */
  public static String[] showDialog(Component comp, String initialValue) {
    if (dialog != null) 
      {
      dialog.setValue(initialValue);
      dialog.setLocationRelativeTo(comp);
      dialog.setVisible(true);
      } 
    else 
      {
      System.err.println("ChooseStringDialog requires you to call initialize "
                               + "before calling showDialog.");
      }
    return values;
  }



  private void setValue(String newValue) {
    if (values == null)
      values = new String[1];
    values[0] = newValue;
    list.setSelectedValue(values[0], true);
  }



  private ChooseStringDialog(Frame frame, Object[] data, String title,
		     String labelText, int selectionModel) {
    super(frame, title, true);

    //buttons
    JButton cancelButton = new JButton("Cancel");
    final JButton setButton = new JButton("Set");
    cancelButton.addActionListener(new ActionListener() {
	public void actionPerformed(ActionEvent e) {
	  ChooseStringDialog.dialog.setVisible(false);
	}
    });

    setButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
	int selectModel = list.getSelectionMode();  
	if (selectModel == ListSelectionModel.SINGLE_SELECTION)
	  {
	  values = new String[1];
	  ChooseStringDialog.values[0] = (String)list.getSelectedValue();
	  }
	else
	  {
	  Object[] listArr = list.getSelectedValues();
	  if (listArr != null)
	    {
	    int numSelections = listArr.length;
	    values = new String[numSelections];
	    for (int i=0; i<numSelections; i++)
	      values[i] = (String)listArr[i];
	    }
	  }
	ChooseStringDialog.dialog.setVisible(false);
      }
    });
    getRootPane().setDefaultButton(setButton);

    //main part of the dialog
    list = new JList(data);
    list.setSelectionMode(selectionModel);
    list.addMouseListener(new MouseAdapter() {
      public void mouseClicked(MouseEvent e) {
	if (e.getClickCount() == 2) 
	  {
	  setButton.doClick();
	  }
      }
    });
    JScrollPane scrollPane = new JScrollPane(list);
    scrollPane.setAlignmentX(LEFT_ALIGNMENT);
    scrollPane.setPreferredSize(new Dimension(250, 80));
    scrollPane.setMinimumSize(new Dimension(250, 80));


    // Create container to hold scroll pane title
    JPanel listPanel = new JPanel();
    listPanel.setLayout(new BoxLayout(listPanel, BoxLayout.Y_AXIS));
    JLabel label = new JLabel(labelText);
    label.setLabelFor(list);
    listPanel.add(label);
    listPanel.add(Box.createRigidArea(new Dimension(0,5)));
    listPanel.add(scrollPane);
    listPanel.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));

    //Lay out the buttons from left to right.
    JPanel buttonPane = new JPanel();
    buttonPane.setLayout(new BoxLayout(buttonPane, BoxLayout.X_AXIS));
    buttonPane.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
    buttonPane.add(Box.createHorizontalGlue());
    buttonPane.add(cancelButton);
    buttonPane.add(Box.createRigidArea(new Dimension(10, 0)));
    buttonPane.add(setButton);

    //Put everything together, using the content pane's BorderLayout.
    Container contentPane = getContentPane();
    contentPane.add(listPanel, BorderLayout.CENTER);
    contentPane.add(buttonPane, BorderLayout.SOUTH);

    pack();
  }
 
}