gnu.prolog.term
Class TermComparator

java.lang.Object
  gnu.prolog.term.TermComparator

All Implemented Interfaces:

Comparator<Term>

public class TermComparator
extends Object
implements Comparator<Term>

comparator for two term

Field Summary

protected int	currentIdx
protected Map<Term,Integer>	orderMap

Constructor Summary

TermComparator()

Method Summary

int	compare(Term o1, Term o2) Compares its two arguments for order.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

equals

Field Detail

currentIdx

protected int currentIdx

orderMap

protected Map<Term,Integer> orderMap

Constructor Detail

TermComparator

public TermComparator()

Method Detail

compare

public int compare(Term o1,
                   Term o2)

Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

The implementor must ensure that sgn(compare(x, y)) == -sgn(compare(y, x)) for all x and y. (This implies that compare(x, y) must throw an exception if and only if compare(y, x) throws an exception.)

The implementor must also ensure that the relation is transitive: ((compare(x, y)>0) && (compare(y, z)>0)) implies compare(x, z)>0.

The implementer must also ensure that x.equals(y) implies that compare(x, y) == 0. Note that the converse is not necessarily true.

Finally, the implementer must ensure that compare(x, y) == 0 implies that sgn(compare(x, z)) == sgn(compare(y, z)), for all z.

Specified by:

compare in interface Comparator<Term>

Returns:

a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

Throws:

ClassCastException - the arguments' types prevent them from being compared by this Comparator.

Since:

JDK1.2