lux.xpath

Class PathStep

java.lang.Object

lux.xpath.AbstractExpression

lux.xpath.PathStep

All Implemented Interfaces:

Visitable

public class PathStep
extends AbstractExpression

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PathStep.Axis

Nested classes/interfaces inherited from class lux.xpath.AbstractExpression

AbstractExpression.Type

Field Summary

Fields

Modifier and Type	Field and Description
static int	MANCESTOR
static int	MATTRIBUTE
static int	MCHILD
static int	MDESCENDANT
static int	MFOLLOWING
static int	MFOLLOWING_SIB
static int	MPARENT
static int	MPRECEDING
static int	MPRECEDING_SIB
static int	MSELF

Fields inherited from class lux.xpath.AbstractExpression

subs, sup

Constructor Summary

Constructors

Constructor and Description
PathStep(PathStep.Axis axis, NodeTest nodeTest)

Method Summary

Methods

Modifier and Type	Method and Description
AbstractExpression	accept(ExpressionVisitor visitor)
int	equivHash()
PathStep.Axis	getAxis()
AbstractExpression	getLastContextStep() This method is called by the optimizer in order to determine an element or attribute QName (or wildcard) against which some expression is being compared, in order to generate an appropriate text query.
NodeTest	getNodeTest()
int	getPrecedence()
boolean	isDocumentOrdered()
boolean	isRestrictive() An expression is restrictive when any empty sub implies the expression is empty.
boolean	propEquals(AbstractExpression other)
boolean	propGreaterEqual(AbstractExpression other)
void	toString(StringBuilder buf) Each subclass must implement the toString(StringBuilder) method by appending itself as a syntatically valid XPath/XQuery expression in the given buffer.

Methods inherited from class lux.xpath.AbstractExpression

acceptSubs, appendSub, deepEquals, equivalent, geq, getBindingContext, getHead, getRoot, getSubs, getSuper, getTail, getType, isAbsolute, matchDown, replaceRoot, setSubs, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

MSELF

public static final int MSELF

See Also:

Constant Field Values

MCHILD

public static final int MCHILD

See Also:

Constant Field Values

MPARENT

public static final int MPARENT

See Also:

Constant Field Values

MDESCENDANT

public static final int MDESCENDANT

See Also:

Constant Field Values

MANCESTOR

public static final int MANCESTOR

See Also:

Constant Field Values

MPRECEDING

public static final int MPRECEDING

See Also:

Constant Field Values

MFOLLOWING

public static final int MFOLLOWING

See Also:

Constant Field Values

MPRECEDING_SIB

public static final int MPRECEDING_SIB

See Also:

Constant Field Values

MFOLLOWING_SIB

public static final int MFOLLOWING_SIB

See Also:

Constant Field Values

MATTRIBUTE

public static final int MATTRIBUTE

See Also:

Constant Field Values

Constructor Detail

PathStep

public PathStep(PathStep.Axis axis,
        NodeTest nodeTest)

Method Detail

getAxis

public PathStep.Axis getAxis()

getNodeTest

public NodeTest getNodeTest()

toString

public void toString(StringBuilder buf)

Description copied from class: AbstractExpression

Each subclass must implement the toString(StringBuilder) method by appending itself as a syntatically valid XPath/XQuery expression in the given buffer.

Specified by:

toString in class AbstractExpression

Parameters:

buf - the buffer to append to

accept

public AbstractExpression accept(ExpressionVisitor visitor)

getPrecedence

public int getPrecedence()

Specified by:

getPrecedence in class AbstractExpression

Returns:

0

isDocumentOrdered

public boolean isDocumentOrdered()

Overrides:

isDocumentOrdered in class AbstractExpression

Returns:

whether this expression is proven to return results in document order. This method returns true iff all its subs return true, or it has none. Warning: incorrect results may occur if document-ordering is falsely asserted.

getLastContextStep

public AbstractExpression getLastContextStep()

Description copied from class: AbstractExpression

This method is called by the optimizer in order to determine an element or attribute QName (or wildcard) against which some expression is being compared, in order to generate an appropriate text query.

Overrides:

getLastContextStep in class AbstractExpression

Returns:

the rightmost path step in the context of this expression.

propEquals

public boolean propEquals(AbstractExpression other)

Overrides:

propEquals in class AbstractExpression

Parameters:

other - another expression

Returns:

whether the other expression and this one have all the same local properties

propGreaterEqual

public boolean propGreaterEqual(AbstractExpression other)

Overrides:

propGreaterEqual in class AbstractExpression

Parameters:

other - another expression of the same type as this

Returns:

whether the expressions' properties imply: this ge oex

equivHash

public int equivHash()

Returns:

a hashcode that is consistent with AbstractExpression.equivalent(AbstractExpression)

isRestrictive

public boolean isRestrictive()

Description copied from class: AbstractExpression

An expression is restrictive when any empty sub implies the expression is empty. In other words, restrictive expressions only return results when all of their subs are non-empty. Eg: and, intersect, predicate, path step.

Overrides:

isRestrictive in class AbstractExpression

Returns:

whether this expression is restrictive