net.sf.saxon.functions

Class CurrentGroup

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.FunctionCall

net.sf.saxon.functions.SystemFunctionCall

net.sf.saxon.functions.CurrentGroup

All Implemented Interfaces:

SourceLocator, Callable, IdentityComparable, InstructionInfo

public class CurrentGroup
extends SystemFunctionCall
implements Callable

Implements the XSLT function current-group()

Field Summary

Fields inherited from class net.sf.saxon.functions.SystemFunctionCall

operation

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

argument

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

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

Constructor Summary

Constructors

Constructor and Description
CurrentGroup()

Method Summary

Methods

Modifier and Type	Method and Description
Sequence	call(XPathContext context, Sequence[] arguments) Evaluate the expression
void	checkArguments(ExpressionVisitor visitor) Method called during static type checking
int	computeSpecialProperties() Determine the special properties of this expression.
Expression	copy() Copy an expression.
ForEachGroup	getControllingInstruction() Get the innermost containing xsl:for-each-group instruction, if there is one
int	getIntrinsicDependencies() Determine the dependencies
ItemType	getItemType() Determine the item type of the value returned by the function
CurrentGroupAdjunct	getStreamingAdjunct() Get a class that supports streamed evaluation of this expression
boolean	isInLoop() Determine whether the current-group() function is executed repeatedly within a single iteration of the containing xsl:for-each-group
SequenceIterator	iterate(XPathContext c) Return an iteration over the result sequence
void	setControllingInstruction(ForEachGroup instruction, ItemType itemType, boolean isInLoop) Set the containing xsl:for-each-group instruction, if there is one

Methods inherited from class net.sf.saxon.functions.SystemFunctionCall

addContextDocumentArgument, addDocToPathMap, bindStaticContext, computeCardinality, equalOrNull, equals, getContextNode, getConvertingCallable, getDefaultArgumentNode, getDetails, getErrorCodeForTypeErrors, getFunctionItemType, getImplementationMethod, getOperation, getRequiredType, makeSystemFunction, operands, optimize, setDetails, toShortString, useContextItemAsDefault

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

addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, preEvaluate, promote, replaceOperand, setArguments, setFunctionName, simplifyArguments, toString, typeCheck

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

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, clearStreamabilityData, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getConfiguration, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExpressionCompiler, getHostLanguage, getIntegerBounds, getLineNumber, getLocationId, getObjectName, getPosture, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamability, getSweep, getSystemId, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isIdentical, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, makeStreamingAdjunct, markTailFunctionCalls, operandList, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, setPostureAndSweep, simplify, staticTypeCheck, suppressValidation, toPattern, toStreamingPattern, typeError, unordered

Methods inherited from class java.lang.Object

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

Constructor Detail

CurrentGroup

public CurrentGroup()

Method Detail

checkArguments

public void checkArguments(ExpressionVisitor visitor)
                    throws XPathException

Description copied from class: SystemFunctionCall

Method called during static type checking

Overrides:

checkArguments in class SystemFunctionCall

Parameters:

visitor - the expression visitor

Throws:

XPathException - if the arguments are incorrect

setControllingInstruction

public void setControllingInstruction(ForEachGroup instruction,
                             ItemType itemType,
                             boolean isInLoop)

Set the containing xsl:for-each-group instruction, if there is one

Parameters:

instruction - the (innermost) containing xsl:for-each-group instruction

itemType - the statically inferred item type of the grouping population

isInLoop - true if the current-group() expression is evaluated more than once during evaluation of the body of the for-each-group instruction

getControllingInstruction

public ForEachGroup getControllingInstruction()

Get the innermost containing xsl:for-each-group instruction, if there is one

Returns:

the innermost containing xsl:for-each-group instruction

isInLoop

public boolean isInLoop()

Determine whether the current-group() function is executed repeatedly within a single iteration of the containing xsl:for-each-group

Returns:

true if it is evaluated repeatedly

getItemType

public ItemType getItemType()

Determine the item type of the value returned by the function

Overrides:

getItemType in class SystemFunctionCall

Returns:

a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)

getIntrinsicDependencies

public int getIntrinsicDependencies()

Determine the dependencies

Overrides:

getIntrinsicDependencies in class Expression

Returns:

a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

computeSpecialProperties

public int computeSpecialProperties()

Determine the special properties of this expression. The properties such as document-ordering are the same as the properties of the grouping population as a whole.

Overrides:

computeSpecialProperties in class SystemFunctionCall

Returns:

StaticProperty.NON_CREATIVE (unless the variable is assignable using saxon:assign)

copy

public Expression copy()

Description copied from class: SystemFunctionCall

Copy an expression. This makes a deep copy.

Overrides:

copy in class SystemFunctionCall

Returns:

the copy of the original expression

iterate

public SequenceIterator iterate(XPathContext c)
                         throws XPathException

Return an iteration over the result sequence

Overrides:

iterate in class Expression

Parameters:

c - supplies the context for evaluation

Returns:

a SequenceIterator that can be used to iterate over the result of the expression

Throws:

XPathException - if any dynamic error occurs evaluating the expression

call

public Sequence call(XPathContext context,
            Sequence[] arguments)
              throws XPathException

Evaluate the expression

Specified by:

call in interface Callable

Parameters:

context - the dynamic evaluation context

arguments - the values of the arguments, supplied as SequenceIterators

Returns:

the result of the evaluation, in the form of a SequenceIterator

Throws:

XPathException - if a dynamic error occurs during the evaluation of the expression

getStreamingAdjunct

public CurrentGroupAdjunct getStreamingAdjunct()

Get a class that supports streamed evaluation of this expression

Overrides:

getStreamingAdjunct in class Expression

Returns:

the relevant StreamingAdjunct, or null if none is available