Package net.sf.saxon.xpath
Class XPathFunctionCall
- java.lang.Object
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- net.sf.saxon.expr.ComputedExpression
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- net.sf.saxon.expr.FunctionCall
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- net.sf.saxon.xpath.XPathFunctionCall
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,Container
,Expression
,InstructionInfoProvider
public class XPathFunctionCall extends FunctionCall
This class is an expression that calls an external function supplied using the JAXP XPathFunction interface- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class net.sf.saxon.expr.FunctionCall
argument
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Fields inherited from class net.sf.saxon.expr.ComputedExpression
locationId, staticProperties
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Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
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Constructor Summary
Constructors Constructor Description XPathFunctionCall(javax.xml.xpath.XPathFunction function)
Default constructor
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description SequenceIterator
call(ValueRepresentation[] argValues, XPathContext context)
Call an extension function previously identified using the bind() method.void
checkArguments(StaticContext env)
Method called by the expression parser when all arguments have been suppliedint
computeCardinality()
Determine the cardinality of the resultint
getIntrinsicDependencies()
Determine which aspects of the context the expression depends on.ItemType
getItemType(TypeHierarchy th)
Determine the data type of the expression, if possible.SequenceIterator
iterate(XPathContext context)
Evaluate the function.Expression
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
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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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Method Detail
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preEvaluate
public Expression 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)- Overrides:
preEvaluate
in classFunctionCall
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checkArguments
public void checkArguments(StaticContext env) throws XPathException
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
public SequenceIterator iterate(XPathContext context) throws XPathException
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
public ItemType getItemType(TypeHierarchy th)
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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