Package net.sf.saxon.xpath
Class XPathFunctionCall
java.lang.Object
net.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.xpath.XPathFunctionCall
- All Implemented Interfaces:
Serializable
,SourceLocator
,Container
,Expression
,InstructionInfoProvider
This class is an expression that calls an external function supplied using the
JAXP XPathFunction interface
- See Also:
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Field Summary
Fields inherited from class net.sf.saxon.expr.FunctionCall
argument
Fields inherited from class net.sf.saxon.expr.ComputedExpression
locationId, staticProperties
Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptioncall
(ValueRepresentation[] argValues, XPathContext context) Call an extension function previously identified using the bind() method.void
Method called by the expression parser when all arguments have been suppliedint
Determine the cardinality of the resultint
Determine which aspects of the context the expression depends on.Determine the data type of the expression, if possible.iterate
(XPathContext context) Evaluate the function.preEvaluate
(StaticContext env) preEvaluate: this method suppresses compile-time evaluation by doing nothing (because the external function might have side-effects and might use the context)Methods inherited from class net.sf.saxon.expr.FunctionCall
checkArgumentCount, display, getArguments, getDisplayName, getFunctionNameCode, getNumberOfArguments, iterateSubExpressions, optimize, promote, replaceSubExpression, setArguments, setFunctionNameCode, simplify, simplifyArguments, typeCheck
Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation, typeError
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Constructor Details
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XPathFunctionCall
Default constructor
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Method Details
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preEvaluate
preEvaluate: this method suppresses compile-time evaluation by doing nothing (because the external function might have side-effects and might use the context)- Overrides:
preEvaluate
in classFunctionCall
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checkArguments
Method called by the expression parser when all arguments have been supplied- Specified by:
checkArguments
in classFunctionCall
- Throws:
XPathException
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getIntrinsicDependencies
public int getIntrinsicDependencies()Determine which aspects of the context the expression depends on. XPath external functions are given no access to context information so they cannot have any dependencies on it.- Overrides:
getIntrinsicDependencies
in classComputedExpression
- 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
Evaluate the function.- Specified by:
iterate
in interfaceExpression
- Overrides:
iterate
in classComputedExpression
- Parameters:
context
- The context in which the function is to be evaluated- Returns:
- a Value representing the result of the function.
- Throws:
XPathException
- if the function cannot be evaluated.
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call
public SequenceIterator call(ValueRepresentation[] argValues, XPathContext context) throws XPathException Call an extension function previously identified using the bind() method. A subclass can override this method.- Parameters:
argValues
- The values of the arguments- Returns:
- The value returned by the extension function
- Throws:
XPathException
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getItemType
Determine the data type of the expression, if possible. All expressions 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 will always return a result, though it may be the best approximation that is available at the time.
- Parameters:
th
-- Returns:
- the item type
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computeCardinality
public int computeCardinality()Determine the cardinality of the result- Specified by:
computeCardinality
in classComputedExpression
- Returns:
- ZERO_OR_MORE (we don't know)
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