// EventTester
//
// Signal when various events occur
// (From "Java in a Nutshell", pp. 90-2)

import java.applet.*;
import java.awt.*;

public class EventTester extends Applet {

  // display the instructions
  public void paint(Graphics g) {
    g.drawString("Click, drag, and type in this window.", 10, 20);
  }

  // handle mouse events
  public boolean mouseDown(Event e, int x, int y) {
    showStatus(modifier_key_names(e.modifiers) +
	       "Mouse Down:  [" + x + "," + y + "]");
    return true;
  }

  public boolean mouseUp(Event e, int x, int y) {
    showStatus(modifier_key_names(e.modifiers) +
	       "Mouse Up:    [" + x + "," + y + "]");
    return true;
  }

  public boolean mouseDrag(Event e, int x, int y) {
    showStatus(modifier_key_names(e.modifiers) +
	       "Mouse Drag:  [" + x + "," + y + "]");
    return true;
  }

  public boolean mouseEnter(Event e, int x, int y) {
    showStatus(modifier_key_names(e.modifiers) +
	       "Mouse Enter: [" + x + "," + y + "]");
    return true;
  }

  public boolean mouseExit(Event e, int x, int y) {
    showStatus(modifier_key_names(e.modifiers) +
	       "Mouse Exit:  [" + x + "," + y + "]");
    return true;
  }


  // handle focus events
  public boolean gotFocus(Event e, Object what) {
    showStatus("Got Focus");
    return true;
  }
  public boolean lostFocus(Event e, Object what) {
    showStatus("Lost Focus");
    return true;
  }

  // handle key down and key up events
  public boolean keyDown(Event e, int key) {
    int flags = e.modifiers;
    if (e.id == Event.KEY_PRESS)           // a regular key
      showStatus("Key Down: "
		 + modifier_key_names(flags)
		 +key_name(e));
    else if (e.id == Event.KEY_ACTION)     // a function key
      showStatus("Function Key Down: "
		 + modifier_key_names(flags)
		 +function_key_name(key));
    return true;
  }

  public boolean keyUp(Event e, int key) {
    int flags = e.modifiers;
    if (e.id == Event.KEY_RELEASE)         // Book is WRONG here!
      showStatus("Key Up:   "
		 + modifier_key_names(flags)
		 +key_name(e));
    else if (e.id == Event.KEY_ACTION)     // a function key
      showStatus("Function Key Up:   "
		 + modifier_key_names(flags)
		 +function_key_name(key));
    return true;
  }


  // The remaining methods help us sort out the various key events
  private String modifier_key_names(int flags) {
    String s = "[";
    if (flags == 0) return "";
    if ((flags & Event.SHIFT_MASK) != 0)   s += "Shift ";
    if ((flags & Event.CTRL_MASK) != 0)    s += "Control ";
    if ((flags & Event.META_MASK) != 0)    s += "Meta ";
    if ((flags & Event.ALT_MASK) != 0)     s += "Alt ";
    s += "]";
    return s;
  }

  // return the name of a regular (ASCII) key
  private String key_name(Event e) {
    char c = (char) e.key;

    // If CTRL flag is set, handle ASCII control characters
    if (e.controlDown()) {
      if (c < ' ') {
	c += '@';
	return "^" + c;
      }
    }
    else {
      // If CTRL flag is not set, then certain ASCII
      // control characters have special meaning.
      switch(c) {
        case '\n':   return "Return";
	case '\t':   return "Tab";
        case '\033': return "Escape";
	case '\010': return "Backspace";
      }
    }

    // handle the remaining possibilities
    if (c == '\177') return "Delete";
    else if (c == ' ') return "Space";
    else return String.valueOf(c);
  }

  // return the name of a function key
  private String function_key_name(int key) {
    switch(key) {
    case Event.UP: return "Up Arrow";
    case Event.DOWN: return "Down Arrow";
    case Event.LEFT: return "Left Arrow";
    case Event.RIGHT: return "Right Arrow";
		 }
    return "Unknown Function Key";
  }

}