Class XPathFunctionCall
- java.lang.Object
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- net.sf.saxon.expr.Expression
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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
,LocationProvider
,SaxonLocator
,EvaluableItem
,SequenceIterable
,InstructionInfo
,org.xml.sax.Locator
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.Expression
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
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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 PathMap.PathMapNodeSet
addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap.protected SequenceIterator
call(ValueRepresentation[] argValues, XPathContext context)
Call an extension function previously identified using the bind() method.void
checkArguments(ExpressionVisitor visitor)
Method called by the expression parser when all arguments have been suppliedint
computeCardinality()
Determine the cardinality of the resultExpression
copy()
Copy an expression.int
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(ExpressionVisitor visitor)
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
addExternalFunctionCallToPathMap, checkArgumentCount, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, optimize, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck
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Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
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Method Detail
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preEvaluate
public Expression preEvaluate(ExpressionVisitor visitor)
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
- Parameters:
visitor
- an expression visitor- Returns:
- the result of the early evaluation, or the original expression, or potentially a simplified expression
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checkArguments
public void checkArguments(ExpressionVisitor visitor) throws XPathException
Method called by the expression parser when all arguments have been supplied- Specified by:
checkArguments
in classFunctionCall
- Parameters:
visitor
- the expression visitor- 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 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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copy
public Expression copy()
Copy an expression. This makes a deep copy.- Specified by:
copy
in classExpression
- Returns:
- the copy of the original expression
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addToPathMap
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.
- Overrides:
addToPathMap
in classExpression
- Parameters:
pathMap
- the PathMap to which the expression should be addedpathMapNodeSet
-- Returns:
- the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.
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iterate
public SequenceIterator iterate(XPathContext context) throws XPathException
Evaluate the function.- Specified by:
iterate
in interfaceSequenceIterable
- Overrides:
iterate
in classExpression
- 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
protected 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 argumentscontext
- The XPath dynamic context- 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.
- Specified by:
getItemType
in classExpression
- Parameters:
th
- the type hierarchy cache- Returns:
- the item type
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computeCardinality
public int computeCardinality()
Determine the cardinality of the result- Specified by:
computeCardinality
in classExpression
- Returns:
- ZERO_OR_MORE (we don't know)
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