net.sf.saxon.functions
Class CurrentGroup

java.lang.Object
  extended by net.sf.saxon.expr.Expression
      extended by net.sf.saxon.expr.FunctionCall
          extended by net.sf.saxon.functions.SystemFunction
              extended by net.sf.saxon.functions.CurrentGroup
All Implemented Interfaces:
Serializable, SourceLocator, EvaluableItem, SequenceIterable, XSLTFunction, InstructionInfoProvider

public class CurrentGroup
extends SystemFunction
implements XSLTFunction

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.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
 
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
addDocToPathMap, checkArguments, computeCardinality, computeSpecialProperties, copy, getDetails, getErrorCodeForTypeErrors, getItemType, makeSystemFunction, optimize, setDetails
 
Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionName, simplify, toString, typeCheck
 
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, effectiveBooleanValue, evaluateAsString, explain, findParentOf, getCardinality, getColumnNumber, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterateEvents, markTailFunctionCalls, process, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation
 
Methods inherited from class java.lang.Object
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


Copyright (C) Michael H. Kay. All rights reserved.