net.sf.saxon.sort

Class TextComparer

Implemented Interfaces:
AtomicComparer, Serializable

public class TextComparer
extends java.lang.Object
implements AtomicComparer, java.io.Serializable

A Comparer used for comparing sort keys when data-type="text". The items to be compared are converted to strings, and the strings are then compared using an underlying collator
Author:
Michael H. Kay
See Also:
Serialized Form

Constructor Summary

TextComparer(AtomicComparer baseComparer)

Method Summary

int
compareAtomicValues(AtomicValue a, AtomicValue b)
Compare two Items by converting them to strings and comparing the string values.
boolean
comparesEqual(AtomicValue a, AtomicValue b)
Compare two AtomicValue objects for equality according to the rules for their data type.
AtomicComparer
getBaseComparer()
Get the underlying comparer (which doesn't do conversion to string)
ComparisonKey
getComparisonKey(AtomicValue a)
Get a comparison key for an object.
AtomicComparer
provideContext(XPathContext context)
Supply the dynamic context in case this is needed for the comparison

Constructor Details

TextComparer

public TextComparer(AtomicComparer baseComparer)

Method Details

compareAtomicValues

public int compareAtomicValues(AtomicValue a,
                               AtomicValue b)
            throws ClassCastException,
                   NoDynamicContextException
Compare two Items by converting them to strings and comparing the string values.
Specified by:
compareAtomicValues in interface AtomicComparer
Parameters:
a - the first Item to be compared.
b - the second Item to be compared.
Returns:
<0 if a0 if a>b

comparesEqual

public boolean comparesEqual(AtomicValue a,
                             AtomicValue b)
            throws NoDynamicContextException
Compare two AtomicValue objects for equality according to the rules for their data type. UntypedAtomic values are compared by converting to the type of the other operand.
Specified by:
comparesEqual in interface AtomicComparer
Parameters:
a - the first object to be compared.
b - the second object to be compared.
Returns:
true if the values are equal, false if not

getBaseComparer

public AtomicComparer getBaseComparer()
Get the underlying comparer (which doesn't do conversion to string)

getComparisonKey

public ComparisonKey getComparisonKey(AtomicValue a)
            throws NoDynamicContextException
Get a comparison key for an object. This must satisfy the rule that if two objects are equal according to the XPath eq operator, then their comparison keys are equal according to the Java equals() method, and vice versa. There is no requirement that the comparison keys should reflect the ordering of the underlying objects.
Specified by:
getComparisonKey in interface AtomicComparer

provideContext

public AtomicComparer provideContext(XPathContext context)
Supply the dynamic context in case this is needed for the comparison
Specified by:
provideContext in interface AtomicComparer
Parameters:
context - the dynamic evaluation context
Returns:
either the original AtomicComparer, or a new AtomicComparer in which the context is known. The original AtomicComparer is not modified