gzz.util
Class LoopDetector

java.lang.Object
  |
  +--gzz.util.LoopDetector

public final class LoopDetector

extends java.lang.Object

A loop detector. Uses a simple constant-space algorithm that will detect any loop before it's cycled through 3 times, except very small loops. Example use:

 	LoopDetector l = new LoopDetector();
	while((x = iter(x)) != null) {
		l.detect(x);
		// ... do something with x.
	}
 

Note: this only works for deterministic loops that always have the same elements and length. Nothing is guaranteed if the content of the loop varies even slightly. However, it is guaranteed that the loop is detected once the loop has settled into a constant loop.

The Object.equals method is used for the comparisons.

Field Summary

static java.lang.String

rcsid

Constructor Summary

LoopDetector()

Method Summary

void	detect(java.lang.Object o) Throws an exception if the parameter is a part of a looping sequence.
void	detectError(java.lang.Object o) Throws an error if bla bla bla.
boolean	isLooping(java.lang.Object o) Returns true if the parameter is a part of a looping sequence.
void	reset()

Methods inherited from class java.lang.Object

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

Field Detail

rcsid

public static final java.lang.String rcsid

See Also:

Constant Field Values

Constructor Detail

LoopDetector

public LoopDetector()

Method Detail

reset

public void reset()

detect

public void detect(java.lang.Object o)
            throws gzz.errors.InfiniteLoopException

Throws an exception if the parameter is a part of a looping sequence.

gzz.errors.InfiniteLoopException

detectError

public void detectError(java.lang.Object o)

Throws an error if bla bla bla.

isLooping

public boolean isLooping(java.lang.Object o)

Returns true if the parameter is a part of a looping sequence.