com.saxonica.ee.trans

Class Precondition.StringHashPrecondition

java.lang.Object

com.saxonica.ee.trans.Precondition

com.saxonica.ee.trans.Precondition.StringHashPrecondition

Enclosing class:

Precondition

public static class Precondition.StringHashPrecondition
extends Precondition

A StringHashPrecondition compares a characteristic in the form of a set of integer hash codes against a constant hash code; the precondition is satisfied if the constant hash code is present in the set.

It is used in two situations:

(a) for a predicate pattern in the form *[EXP = 'constant'] where the constant hash code is the hash code of the collation key of the constant string, and the characteristic is the set of hash codes corresponding to the collation keys of the strings selected by evaluating EXP.

(b) for a predicate pattern in the form *[contains(EXP, ' constant ')], typically encountered in DITA stylesheets, where the constant hash code is the hash code of the collation key of the token being matched (the constant with whitespace trimmed), and the characteristic is the set of hash codes corresponding to the collation keys of the tokens found by evaluating EXP and splitting on whitespace boundaries.

Nested Class Summary

Nested classes/interfaces inherited from class com.saxonica.ee.trans.Precondition

Precondition.BooleanPrecondition, Precondition.NumericComparisonPrecondition, Precondition.StringHashPrecondition

Constructor Summary

Constructors

Constructor and Description
StringHashPrecondition(Characteristic<IntSet> characteristic, AtomicMatchKey required, StringCollator collator) Create a StringHashPrecondition

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object obj)
int	hashCode()
boolean	testPrecondition(PreconditionMatcher matcher) Compute the value of the precondition for a given item.
java.lang.String	toString()

Methods inherited from class com.saxonica.ee.trans.Precondition

isSatisfied, setSlotNumber

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

StringHashPrecondition

public StringHashPrecondition(Characteristic<IntSet> characteristic,
                              AtomicMatchKey required,
                              StringCollator collator)

Create a StringHashPrecondition

Parameters:

characteristic - the characteristic that is tested by this precondition. This must evaluate to a set of hashcodes for permitted string values. The precondition is satisfied if the set of hash codes obtained as the value of the characteristic includes the hash code of the required key value. For example, given match=*[author='Kay'], the characteristic will be the set of hash codes of the values of 'author' children of the context item; the precondition is satisfied if this includes the hash code of the string 'Kay' under the specified collation.

required - the required key value, whose hash code must match one of the values in the IntSet value of the characteristic

collator - the collation to be used for comparison

Method Detail

testPrecondition

public boolean testPrecondition(PreconditionMatcher matcher)
                         throws XPathException

Description copied from class: Precondition

Compute the value of the precondition for a given item. The item in question is the context item in the dynamic context held in the PreconditionMatcher

Specified by:

testPrecondition in class Precondition

Parameters:

matcher - the PreconditionMatcher: holds the dynamic context for evaluation.

Returns:

true if the precondition is satisfied

Throws:

XPathException - if evaluation of the precondition fails with a dynamic error

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object