edu.kzoo.util
Class Debug

java.lang.Object
  |
  +--edu.kzoo.util.Debug

public class Debug

extends java.lang.Object

AP® Computer Science Marine Biology Simulation:
The Debug class supports conditional printing of debugging messages.

The turnOn and turnOff methods cause the previous debugging state to be saved on a stack so that it can be restored later using the restoreState method.

For example, consider the following scenario. Method 1 turns on debugging and calls Method 2. Method 2, not knowing that debugging is already on, turns debugging on and calls Method 3. Method 3 turns debugging off. Before returning, Method 3 restores the previous state, which turns debugging back on (as set by Method 2). Before Method 2 returns, it also restores the state, which will leave debugging on (as set by Method 1). This is illustrated in the pseudo-code below.

      in Method 1:
          (A: in Method 1; we don't know debugging state)
          turn on debugging
          (debugging state is now on; Debug.println will print)
          call Method 2
              (B: now in Method 2; debugging state is unchanged (on))
              turn on debugging
              (debugging state is on (still))
              call Method 3
                  (C: now in Method 3; debugging state is unchanged (on))
                  turn off debugging
                  (debugging state is now off; Debug.println will not print)
                  restore state
                  (debugging state is restored to what it was at point C (on))
                  return to Method 2
               (D: now in Method 2; debugging state is unchanged (still on))
               restore state
               (debugging state is still on because it was on at point B)
               return to Method 1
           (E: now in Method 1; debugging state unchanged (still on))
           restore state
           (debugging state is whatever it was at point A (unknown))
  

Note that when Method 2 restores the debugging state, it does not go back to its most recent state, which would be off (as set by Method 3). State restoration is controlled by a stack, not by a toggle.

The Debug class is copyright© 2002 College Entrance Examination Board (www.collegeboard.com).

Version:

1 July 2002

Author:

Alyce Brady

Constructor Summary

Debug()

Method Summary

static boolean	isOff() Checks whether debugging is off.
static boolean	isOn() Checks whether debugging is on.
static void	print(java.lang.String message) Prints debugging message without appending a newline character at the end.
static void	println(java.lang.String message) Prints debugging message, appending a newline character at the end.
static void	restoreState() Restores the previous debugging state.
static void	turnOff() Turns debugging off.
static void	turnOn() Turns debugging on.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Debug

public Debug()

Method Detail

isOn

public static boolean isOn()

Checks whether debugging is on. The Debug.print and Debug.println) methods use isOn to decide whether or not to print.

isOff

public static boolean isOff()

Checks whether debugging is off.

turnOn

public static void turnOn()

Turns debugging on.

turnOff

public static void turnOff()

Turns debugging off.

restoreState

public static void restoreState()

Restores the previous debugging state. If there is no previous state to restore, restoreState turns debugging off.

print

public static void print(java.lang.String message)

Prints debugging message without appending a newline character at the end. If debugging is turned on, message is printed to System.out without a newline.

Parameters:

message - debugging message to print

println

public static void println(java.lang.String message)

Prints debugging message, appending a newline character at the end. If debugging is turned on, message is printed to System.out followed by a newline.

Parameters:

message - debugging message to print