FifteenEvent.java

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

/**
 * @author SilverKitsune
 */
public class FifteenEvent implements ActionListener

    {
    /**
     * Moves the button clicked, where possible.
     */
    public void actionPerformed(ActionEvent ae)
        {
        JButton b = (JButton)ae.getSource();
        int x = b.getX();
        int y = b.getY();
        int dx = (int)b.getMaximumSize().getWidth();
        int dy = (int)b.getMaximumSize().getHeight();
        if(x + dx <= 4 * dx && checkFree(b, x + dx, y))
            b.setLocation(x + dx, y);
        else if(x - dx >= 0 && checkFree(b, x - dx, y))
            b.setLocation(x - dx, y);
        else if(y + dy <= 4 * dy && checkFree(b, x, y + dy))
            b.setLocation(x, y + dy);
        else if(y - dy >= 0 && checkFree(b, x, y - dy))
            b.setLocation(x, y - dy);
        else;
        }

    /**
     * Checks if the button can be moved.
     * @param b The button to move.
     * @param x The new X coordinate of the button.
     * @param y The new Y coordinate of the button.
     * @return True if the button can be moved, false otherwise.
     */
    private boolean checkFree(JButton b, int x, int y)
        {
        return b.getParent().getComponentAt(x, y) != FifteenFrame.one &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.two &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.three &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.four &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.five &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.six &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.seven &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.eight &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.nine &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.ten &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.eleven &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.twelve &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.thirteen &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.fourteen &&
                b.getParent().getComponentAt(x, y) != FifteenFrame.fifteen;
        }
    }