org.exolab.adaptx.xpath.expressions

Class PathExpr

public abstract class PathExpr extends Object implements XPathExpression, MatchExpression

An abstract class representing an XPath Location Path expression.

Version: $Revision: 3734 $ $Date: 2003-05-13 03:55:04 -0400 (Tue, 13 May 2003) $

Author: Keith Visco

Method Summary
abstract XPathResultevaluate(XPathContext context)
Evaluates the expression and returns the XPath result.
abstract doublegetDefaultPriority()
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.
  
shortgetExprType()
Returns the XPathExpression type
abstract PathComponentgetPathComponent()
Returns the PathComponent for the this PathExpr, either a FilterExpr or LocationStep.
abstract PathExprgetSubPath()
abstract booleanisAbsolute()
Returns true if this PathExpr is an absolute expression, otherwise false (ie. it's a relative expression).
abstract booleanmatches(XPathNode node, XPathContext context)
Determines if the given node is matched by this MatchExpr with respect to the given context.

Method Detail

evaluate

public abstract XPathResult evaluate(XPathContext context)
Evaluates the expression and returns the XPath result.

Parameters: context The XPathContext to use during evaluation.

Returns: The XPathResult (not null).

Throws: XPathException if an error occured while evaluating this expression.

getDefaultPriority

public abstract 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

getExprType

public final short getExprType()
Returns the XPathExpression type

Returns: the XPathExpression type

See Also: XPathExpression

getPathComponent

public abstract PathComponent getPathComponent()
Returns the PathComponent for the this PathExpr, either a FilterExpr or LocationStep.

Returns: the PathComponent for this PathExpr

getSubPath

public abstract PathExpr getSubPath()

isAbsolute

public abstract boolean isAbsolute()
Returns true if this PathExpr is an absolute expression, otherwise false (ie. it's a relative expression).

Returns: true if this PathExpr is an absolute expression.

matches

public abstract boolean matches(XPathNode node, XPathContext context)
Determines if the given node is matched by this MatchExpr with respect to the given context.

Parameters: node the node to determine a match for context the XPathContext

Returns: true if the given node is matched by this MatchExpr

Throws: XPathException when an error occurs during evaluation