org.exolab.adaptx.xpath.engine
Class FilterBase

java.lang.Object
  |
  +--org.exolab.adaptx.xpath.engine.FilterBase

All Implemented Interfaces:

MatchExpression, PathComponent, XPathExpression

public abstract class FilterBase

extends java.lang.Object

implements PathComponent

The base class for filters (now basically called paths)

Version:

$Revision: 1.2 $ $Date: 2003/05/13 07:59:08 $

Author:

Keith Visco

Field Summary

static int	NO_OP
static int	PARENT_OP

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

Constructor Summary

FilterBase(int ancestryOp)
Creates a new FilterBase

Method Summary

void	addPredicate(org.exolab.adaptx.xpath.engine.PredicateExprImpl predicate) Adds the given Expression to this FilterBase's predicate List.
void	addPredicate(XPathExpression expr) Adds the given Expression to this FilterBase's predicate List.
abstract XPathResult	evaluate(XPathContext context) Evaluates the expression and returns the XPath result.
void	evaluatePredicates(NodeSet nodes, XPathContext context) Evaluates the PredicateExpr of this FilterBase against the given Node.
int	getAncestryOp()
abstract double	getDefaultPriority() Determines the priority of a PatternExpr as follows:
abstract short	getExprType() Returns the type of this expression.
PredicateExpr	getPredicate() Returns the PredicateExpr of this Filter
boolean	hasPredicates() Returns true if this FilterBase has predicates expressions.
abstract boolean	matches(XPathNode node, XPathContext context) Determines if the given node is matched by this MatchExpr with respect to the given context.
java.lang.String	toString() Returns the String representation of this FilterBase

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

NO_OP

public static final int NO_OP

See Also:

Constant Field Values

PARENT_OP

public static final int PARENT_OP

See Also:

Constant Field Values

Constructor Detail

FilterBase

public FilterBase(int ancestryOp)

Creates a new FilterBase

Method Detail

addPredicate

public void addPredicate(XPathExpression expr)
                  throws XPathException

Adds the given Expression to this FilterBase's predicate List.

Parameters:

expr - the Expr to add to the predicate list

XPathException

addPredicate

public void addPredicate(org.exolab.adaptx.xpath.engine.PredicateExprImpl predicate)
                  throws XPathException

Adds the given Expression to this FilterBase's predicate List.

XPathException

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
 

Specified by:

getDefaultPriority in interface PathComponent

Returns:

the priority for this PatternExpr

getExprType

public abstract short getExprType()

Description copied from interface: XPathExpression

Returns the type of this expression.

Specified by:

getExprType in interface XPathExpression

Returns:

The type of this expression

evaluate

public abstract XPathResult evaluate(XPathContext context)
                              throws XPathException

Evaluates the expression and returns the XPath result.

Specified by:

evaluate in interface XPathExpression

Parameters:

context - The XPathContext to use during evaluation.

Returns:

The XPathResult (not null).

Throws:

XPathException - if an error occured while evaluating this expression.

getPredicate

public PredicateExpr getPredicate()

Returns the PredicateExpr of this Filter

Specified by:

getPredicate in interface PathComponent

Returns:

the PredicateExpr of this Filter

hasPredicates

public boolean hasPredicates()

Returns true if this FilterBase has predicates expressions.

Specified by:

hasPredicates in interface PathComponent

Returns:

true if this FilterBase has predicates expressions.

evaluatePredicates

public void evaluatePredicates(NodeSet nodes,
                               XPathContext context)
                        throws XPathException

Evaluates the PredicateExpr of this FilterBase against the given Node.

Specified by:

evaluatePredicates in interface PathComponent

Parameters:

nodes - the current NodeSet

context - the XPathContext for use during evaluation.

XPathException

getAncestryOp

public int getAncestryOp()

matches

public abstract boolean matches(XPathNode node,
                                XPathContext context)
                         throws XPathException

Determines if the given node is matched by this MatchExpr with respect to the given context.

Specified by:

matches in interface MatchExpression

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

toString

public java.lang.String toString()

Returns the String representation of this FilterBase

Specified by:

toString in interface XPathExpression

Overrides:

toString in class java.lang.Object

Returns:

the String representation of this FilterBase