net.sf.saxon.pattern

Class BooleanExpressionPattern

java.lang.Object

net.sf.saxon.pattern.Pattern

net.sf.saxon.pattern.BooleanExpressionPattern

All Implemented Interfaces:

Serializable, SourceLocator, Container, PatternFinder

public class BooleanExpressionPattern
extends Pattern

A BooleanExpressionPattern is a pattern of the form ?{ Expr } introduced in XSLT 3.0. It matches an item if the expression has an effective boolean value of true() when evaluated with that item as the singleton focus.

Author:

Michael H. Kay

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
BooleanExpressionPattern(Expression expression) Create a BooleanExpressionPattern

Method Summary

Methods

Modifier and Type	Method and Description
int	allocateSlots(SlotManager slotManager, int nextFree) Allocate slots to any variables used within the pattern
Pattern	analyze(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) Type-check the pattern.
boolean	equals(Object other) Determine whether this pattern is the same as another pattern
double	getDefaultPriority() Determine the default priority of this item type test when used on its own as a Pattern
int	getFingerprint() Determine the name fingerprint of nodes to which this pattern applies.
ItemType	getItemType() Get an Itemtype that all the items matching this pattern must satisfy
int	getNodeKind() Determine the types of nodes to which this pattern applies.
int	hashCode() Hashcode supporting equals()
Iterator<Expression>	iterateSubExpressions() Iterate over the subexpressions within this pattern
boolean	matches(Item item, XPathContext context) Determine whether this Pattern matches the given item.
String	toString() Display the pattern for diagnostics

Methods inherited from class net.sf.saxon.pattern.Pattern

bindCurrent, getColumnNumber, getContainerGranularity, getDependencies, getExecutable, getHostLanguage, getLineNumber, getLocationProvider, getPublicId, getSystemId, isMotionless, make, matchesBeneathAnchor, promote, replaceCurrent, replaceSubExpression, selectNodes, setExecutable, setLineNumber, setOriginalText, setSystemId, simplify

Methods inherited from class java.lang.Object

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

Constructor Detail

BooleanExpressionPattern

public BooleanExpressionPattern(Expression expression)

Create a BooleanExpressionPattern

Parameters:

expression - the expression to be evaluated

Method Detail

allocateSlots

public int allocateSlots(SlotManager slotManager,
                int nextFree)

Allocate slots to any variables used within the pattern

Overrides:

allocateSlots in class Pattern

Parameters:

slotManager - holds details of the allocated slots

nextFree - the next slot that is free to be allocated @return the next slot that is free to be allocated

Returns:

the next slot that is free to be allocated

iterateSubExpressions

public Iterator<Expression> iterateSubExpressions()

Iterate over the subexpressions within this pattern

Overrides:

iterateSubExpressions in class Pattern

Returns:

an iterator over the subexpressions. Default implementation returns an empty sequence

analyze

public Pattern analyze(ExpressionVisitor visitor,
              ExpressionVisitor.ContextItemType contextItemType)
                throws XPathException

Type-check the pattern.

Overrides:

analyze in class Pattern

Parameters:

visitor - the expression visitor

contextItemType - the type of the context item at the point where the pattern is defined. Set to null if it is known that the context item is undefined.

Returns:

the optimised Pattern

Throws:

XPathException

matches

public boolean matches(Item item,
              XPathContext context)

Determine whether this Pattern matches the given item. This is the main external interface for matching patterns: it sets current() to the node being tested

Specified by:

matches in class Pattern

Parameters:

item - The item to be tested against the Pattern

context - The context in which the match is to take place. Only relevant if the pattern uses variables, or contains calls on functions such as document() or key().

Returns:

true if the item matches the Pattern, false otherwise

getItemType

public ItemType getItemType()

Get an Itemtype that all the items matching this pattern must satisfy

Specified by:

getItemType in class Pattern

Returns:

an ItemType, as specific as possible, which all the matching items satisfy

getDefaultPriority

public final double getDefaultPriority()

Determine the default priority of this item type test when used on its own as a Pattern

Overrides:

getDefaultPriority in class Pattern

Returns:

the default priority for the pattern

getNodeKind

public int getNodeKind()

Determine the types of nodes to which this pattern applies. Used for optimisation. For patterns that match nodes of several types, return Type.NODE. For patterns that do not match nodes, return -1.

Overrides:

getNodeKind in class Pattern

Returns:

the type of node matched by this pattern. e.g. Type.ELEMENT or Type.TEXT

getFingerprint

public int getFingerprint()

Determine the name fingerprint of nodes to which this pattern applies. Used for optimisation.

Overrides:

getFingerprint in class Pattern

Returns:

A fingerprint that the nodes must match, or -1 if it can match multiple fingerprints

toString

public String toString()

Display the pattern for diagnostics

Overrides:

toString in class Pattern

equals

public boolean equals(Object other)

Determine whether this pattern is the same as another pattern

Overrides:

equals in class Object

Parameters:

other - the other object

hashCode

public int hashCode()

Hashcode supporting equals()

Overrides:

hashCode in class Object