net.sf.saxon.functions
Class CurrentGroup

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.FunctionCall
          net.sf.saxon.functions.SystemFunction
              net.sf.saxon.functions.CurrentGroup

All Implemented Interfaces:

Serializable, SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, InstructionInfo, Locator

public class CurrentGroup
extends SystemFunction

Implements the XSLT functions current-group() and current-grouping-key()

See Also:

Serialized Form

Field Summary

static int	CURRENT_GROUP
static int	CURRENT_GROUPING_KEY

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

operation

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

argument

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

EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties

Constructor Summary

CurrentGroup()

Method Summary

Item	evaluateItem(XPathContext c) Evaluate the expression
int	getIntrinsicDependencies() Determine the dependencies
SequenceIterator	iterate(XPathContext c) Return an iteration over the result sequence
Expression	preEvaluate(ExpressionVisitor visitor) preEvaluate: this method suppresses compile-time evaluation by doing nothing (because the value of the expression depends on the runtime context)

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

addContextDocumentArgument, addDocToPathMap, checkArguments, computeCardinality, computeSpecialProperties, copy, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault

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

addExternalFunctionCallToPathMap, checkArgumentCount, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck

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

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError

Methods inherited from class java.lang.Object

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

Field Detail

CURRENT_GROUP

public static final int CURRENT_GROUP

See Also:

Constant Field Values

CURRENT_GROUPING_KEY

public static final int CURRENT_GROUPING_KEY

See Also:

Constant Field Values

Constructor Detail

CurrentGroup

public CurrentGroup()

Method Detail

preEvaluate

public Expression preEvaluate(ExpressionVisitor visitor)

preEvaluate: this method suppresses compile-time evaluation by doing nothing (because the value of the expression depends on the runtime context)

Overrides:

preEvaluate in class FunctionCall

Parameters:

visitor - an expression visitor

Returns:

the result of the early evaluation, or the original expression, or potentially a simplified expression

evaluateItem

public Item evaluateItem(XPathContext c)
                  throws XPathException

Evaluate the expression

Specified by:

evaluateItem in interface EvaluableItem

Overrides:

evaluateItem in class Expression

Parameters:

c - The context in which the expression is to be evaluated

Returns:

the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence

Throws:

XPathException - if any dynamic error occurs evaluating the expression

iterate

public SequenceIterator iterate(XPathContext c)
                         throws XPathException

Return an iteration over the result sequence

Specified by:

iterate in interface SequenceIterable

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

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