Class CurrentGroupingKeyCall
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.functions.CurrentGroupingKeyCall
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- All Implemented Interfaces:
Callable
,ExportAgent
,Locatable
,IdentityComparable
,Traceable
public class CurrentGroupingKeyCall extends Expression implements Callable
Implements the XSLT function current-grouping-key()
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Field Summary
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Fields inherited from class net.sf.saxon.expr.Expression
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_COST, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD
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Constructor Summary
Constructors Constructor Description CurrentGroupingKeyCall()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Sequence
call(XPathContext context, Sequence[] arguments)
Call the Callable.protected int
computeCardinality()
Compute the static cardinality of this expressionExpression
copy(RebindingMap rebindings)
Copy an expression.void
export(ExpressionPresenter out)
Diagnostic print of expression structure.int
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().int
getIntrinsicDependencies()
Determine the dependenciesItemType
getItemType()
Determine the data type of the expression, if possible.Expression
getScopingExpression()
Get the innermost scoping expression of this expression, for expressions that directly depend on something in the dynamic context.SequenceIterator
iterate(XPathContext c)
Evaluate the expression-
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeHashCode, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, equals, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getCost, getDependencies, getEvaluationMethod, getExpressionName, getExtraProperty, getIntegerBounds, getInterpretedExpression, getLocalRetainedStaticContext, getLocation, getNetCost, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, getStreamerName, getTracingTag, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isInstruction, isLiftable, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, markTailFunctionCalls, operandList, operands, operandSparseList, optimize, optimizeChildren, prepareForStreaming, process, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, toShortString, toString, typeCheck, typeCheckChildren, typeError, unordered, verifyParentPointers
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface net.sf.saxon.trace.Traceable
gatherProperties
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Method Detail
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getScopingExpression
public Expression getScopingExpression()
Get the innermost scoping expression of this expression, for expressions that directly depend on something in the dynamic context. For example, in the case of a local variable reference this is the expression that causes the relevant variable to be bound; for a context item expression it is the innermost focus-setting container. For expressions that have no intrinsic dependency on the dynamic context, the value returned is null; the scoping container for such an expression is the innermost scoping container of its operands.- Overrides:
getScopingExpression
in classExpression
- Returns:
- the innermost scoping container of this expression
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computeCardinality
protected int computeCardinality()
Compute the static cardinality of this expression- Specified by:
computeCardinality
in classExpression
- Returns:
- the computed cardinality, as one of the values
StaticProperty.ALLOWS_ZERO_OR_ONE
,StaticProperty.EXACTLY_ONE
,StaticProperty.ALLOWS_ONE_OR_MORE
,StaticProperty.ALLOWS_ZERO_OR_MORE
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getImplementationMethod
public int getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided directly. The other methods will always be available indirectly, using an implementation that relies on one of the other methods.- Specified by:
getImplementationMethod
in classExpression
- Returns:
- the implementation method, for example
Expression.ITERATE_METHOD
orExpression.EVALUATE_METHOD
orExpression.PROCESS_METHOD
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getItemType
public ItemType getItemType()
Determine the data type of the expression, if possible. All expression return sequences, in general; this method determines the type of the items within the sequence, assuming that (a) this is known in advance, and (b) it is the same for all items in the sequence.This method should always return a result, though it may be the best approximation that is available at the time.
- Specified by:
getItemType
in classExpression
- Returns:
- a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)
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export
public void export(ExpressionPresenter out) throws XPathException
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Specified by:
export
in interfaceExportAgent
- Specified by:
export
in classExpression
- Parameters:
out
- the expression presenter used to display the structure- Throws:
XPathException
- if the export fails, for example if an expression is found that won't work in the target environment.
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copy
public Expression copy(RebindingMap rebindings)
Copy an expression. This makes a deep copy.- Specified by:
copy
in classExpression
- Parameters:
rebindings
-- Returns:
- the copy of the original expression
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getIntrinsicDependencies
public int getIntrinsicDependencies()
Determine the dependencies- Overrides:
getIntrinsicDependencies
in classExpression
- Returns:
- a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
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iterate
public SequenceIterator iterate(XPathContext c) throws XPathException
Evaluate the expression- Overrides:
iterate
in classExpression
- 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
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call
public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException
Call the Callable.- Specified by:
call
in interfaceCallable
- Parameters:
context
- the dynamic evaluation contextarguments
- the values of the arguments, supplied as Sequences.Generally it is advisable, if calling iterate() to process a supplied sequence, to call it only once; if the value is required more than once, it should first be converted to a
GroundedValue
by calling the utility method SequenceTool.toGroundedValue().If the expected value is a single item, the item should be obtained by calling Sequence.head(): it cannot be assumed that the item will be passed as an instance of
Item
orAtomicValue
.It is the caller's responsibility to perform any type conversions required to convert arguments to the type expected by the callee. An exception is where this Callable is explicitly an argument-converting wrapper around the original Callable.
- Returns:
- the result of the evaluation, in the form of a Sequence. It is the responsibility of the callee to ensure that the type of result conforms to the expected result type.
- Throws:
XPathException
- if a dynamic error occurs during the evaluation of the expression
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