net.sf.saxon.pattern

Class BooleanExpressionPattern

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.PseudoExpression

net.sf.saxon.pattern.Pattern

net.sf.saxon.pattern.BooleanExpressionPattern

All Implemented Interfaces:

IdentityComparable

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

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression

EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD

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	copy() Copy a pattern.
boolean	equals(Object other) Determine whether this pattern is the same as another pattern
void	export(ExpressionPresenter presenter) Diagnostic print of expression structure.
Expression	getExpression()
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
UType	getUType() Get a UType indicating which kinds of items this Pattern can match.
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.
Iterable<Operand>	operands() Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression.
String	toString() Display the pattern for diagnostics
Pattern	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) Type-check the pattern.

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

bindCurrent, convertToTypedPattern, effectiveBooleanValue, getDefaultPriority, getDependencies, getHostLanguage, isMotionless, make, matchesBeneathAnchor, optimize, promote, replaceCurrent, selectNodes, setOriginalText, setPriority, simplify

Methods inherited from class net.sf.saxon.expr.PseudoExpression

computeCardinality, evaluateAsString, evaluateItem, getImplementationMethod, iterate, iterateEvents, process

Methods inherited from class net.sf.saxon.expr.Expression

addToPathMap, adoptChildExpression, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, clearStreamabilityData, computeDependencies, computeSpecialProperties, computeStaticProperties, doPromotion, dynamicError, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getConstructType, getCost, getEvaluationMethod, getExpressionCompiler, getExpressionName, getIntegerBounds, getIntrinsicDependencies, getLocation, getNetCost, getObjectName, getPackageData, getParentExpression, getPosture, getPostureAndSweepIfKnown, getProperties, getProperty, getRetainedStaticContext, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStreamability, getStreamingAdjunct, getSweep, getSystemId, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isCallOnSystemFunction, isIdentical, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, makeStreamingAdjunct, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, optimizeForType, promote, promoteChildren, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setFiltered, setFlattened, setLocation, setParentExpression, setPostureAndSweep, setRetainedStaticContext, setRetainedStaticContextLocally, setStaticProperty, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, toShortString, toStreamingPattern, typeCheckChildren, typeError, unordered

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 (the expression in the predicate)

Method Detail

operands

public Iterable<Operand> operands()

Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression. Default implementation works off the results of iterateSubExpressions()

If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.

Overrides:

operands in class Expression

Returns:

an iterator containing the sub-expressions of this expression

getUType

public UType getUType()

Get a UType indicating which kinds of items this Pattern can match.

Specified by:

getUType in class Pattern

Returns:

a UType indicating all the primitive types of item that the pattern can match.

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

typeCheck

public Pattern typeCheck(ExpressionVisitor visitor,
                ContextItemStaticInfo contextItemType)
                  throws XPathException

Type-check the pattern.

Overrides:

typeCheck 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 - if an error is discovered during this phase (typically a type error)

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

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

Returns:

a representation of the expression as a string

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

copy

public Pattern copy()

Copy a pattern. This makes a deep copy.

Specified by:

copy in class Pattern

Returns:

the copy of the original pattern

export

public void export(ExpressionPresenter presenter)

Description copied from class: Expression

Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

Specified by:

export in class Pattern

Parameters:

presenter - the expression presenter used to display the structure

getExpression

public Expression getExpression()