net.sf.saxon.sort

Class NumericComparer

java.lang.Object

net.sf.saxon.sort.NumericComparer

All Implemented Interfaces:

Serializable, Comparator

public class NumericComparer
extends Object
implements Comparator, Serializable

A Comparer used for comparing sort keys when data-type="number". The items to be compared are converted to numbers, and the numbers are then compared directly.

This class is used in XSLT only, so there is no need to handle XQuery's "empty least" vs "empty greatest" options.

Author:

Michael H. Kay

See Also:

Serialized Form

Method Summary

Modifier and Type	Method and Description
int	compare(Object a, Object b) Compare two Items by converting them to numbers and comparing the numeric values.
static NumericComparer	getInstance()

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

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Method Detail

getInstance

public static NumericComparer getInstance()

compare

public int compare(Object a,
                   Object b)

Compare two Items by converting them to numbers and comparing the numeric values. If either value cannot be converted to a number, it is treated as NaN, and compares less that the other (two NaN values compare equal).

Specified by:

compare in interface Comparator

Parameters:

a - the first Item to be compared.

b - the second Item to be compared.

Returns:

<0 if a0 if a>b

Throws:

ClassCastException - if the objects are not Items