Package org.exolab.adaptx.xpath.expressions

Interface PathComponent

All Superinterfaces:

MatchExpression, XPathExpression

All Known Subinterfaces:

FilterExpr, LocationStep

All Known Implementing Classes:

AbstractPathComponent

public interface PathComponent
extends XPathExpression, MatchExpression

A basic interface for LocationStep or FilterExpr

Version:

$Revision: 4050 $ $Date: 2004-01-13 07:04:15 +0100 (Tue, 13 Jan 2004) $

Author:

Keith Visco

Field Summary

Fields inherited from interface org.exolab.adaptx.xpath.XPathExpression

BOOLEAN, ERROR, FILTER_EXPR, LOCATION_PATH, NODE_TEST, NUMBER, PATH_EXPR, PRIMARY, STEP, STRING, UNION_EXPR

Method Summary

Modifier and Type	Method	Description
void	evaluatePredicates(NodeSet nodes, XPathContext context)	Evaluates the PredicateExpr of this PathComponent against the given NodeSet and XPathContext.
double	getDefaultPriority()	Determines the priority of a PatternExpr as follows:
PredicateExpr	getPredicate()	Returns the PredicateExpr of this PathComponent
XPathExpression	getSubExpression()	Returns the sub-expression encapsulated by this PathComponent.
boolean	hasPredicates()	Returns true if this PathComponent has predicates expressions.
boolean	isFilterExpr()	Returns true if this PathComponent is a FilterExpr.
boolean	isLocationStep()	Returns true if this PathComponent is a LocationStep.

Methods inherited from interface org.exolab.adaptx.xpath.expressions.MatchExpression

matches

Methods inherited from interface org.exolab.adaptx.xpath.XPathExpression

evaluate, getExprType, toString

Method Detail

isFilterExpr

boolean isFilterExpr()

Returns true if this PathComponent is a FilterExpr. Note that if this method returns true, then a call to #isLocationStep must return false.

Returns:

true if this PathComponent is a FilterExpr

See Also:

isLocationStep()

isLocationStep

boolean isLocationStep()

Returns true if this PathComponent is a LocationStep. Note that if this method returns true, then a call to #isFilterExpr must return false.

Returns:

true if this PathComponent is a LocationStep

See Also:

isFilterExpr()

getDefaultPriority

double getDefaultPriority()

Determines the priority of a PatternExpr as follows:

  From the 19991116 XSLT 1.0 Recommendation:
  + If the pattern has the form of a QName preceded by a
    ChildOrAttributeAxisSpecifier or has the form 
    processing-instruction(Literal) then the priority is 0.
  + If the pattern has the form NCName:* preceded by a 
    ChildOrAttributeAxisSpecifier, then the priority is -0.25
  + Otherwise if the pattern consists of just a NodeTest 
    preceded by a ChildOrAttributeAxisSpecifier then the
    priority is -0.5
  + Otherwise the priority is 0.5
 

Returns:

the priority for this PatternExpr

getSubExpression

XPathExpression getSubExpression()

Returns the sub-expression encapsulated by this PathComponent. the sub-expression will either be a PrimaryExpr if this PathComponent is a FilterExpr, or a NodeExpression if this Pathcomponent is a LocationStep. This method may return null if no such sub-expression exists for the PathComponent.

Returns:

the sub-expression encapsulated by this PathComponent.

evaluatePredicates

void evaluatePredicates(NodeSet nodes,
                        XPathContext context)
                 throws XPathException

Evaluates the PredicateExpr of this PathComponent against the given NodeSet and XPathContext.

Parameters:

nodes - the current NodeSet

context - the XPathContext for use during evaluation.

Throws:

XPathException

getPredicate

PredicateExpr getPredicate()

Returns the PredicateExpr of this PathComponent

Returns:

the PredicateExpr of this PathComponent

hasPredicates

boolean hasPredicates()

Returns true if this PathComponent has predicates expressions.

Returns:

true if this PathComponent has predicates expressions.