Package net.sf.saxon.expr
Class UserFunctionCall
java.lang.Object
net.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.expr.UserFunctionCall
- All Implemented Interfaces:
Serializable
,SourceLocator
,Container
,Expression
,InstructionInfoProvider
This class represents a call to a function defined in the stylesheet or query.
It is used for all user-defined functions in XQuery, and for a limited class of
user-defined functions in XSLT: those that can be reduced to the evaluation
of a single expression.
- 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 TypeMethodDescriptionvoid
Method called during the type checking phasevoid
checkFunctionCall
(UserFunction compiledFunction, StaticContext env) Check the function call against the declared function signaturevoid
int
Determine the cardinality of the resultvoid
display
(int level, PrintStream out, Configuration config) Diagnostic print of expression structure.dynamicCall
(ValueRepresentation[] suppliedArguments, XPathContext context) Call the function dynamically.Call the function, returning the value as an item.Get the arguments (the expressions supplied in the function call)Get the function that is being called by this function callint
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().Get diagnostic information about this expressionint
Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.Determine the data type of the expression, if possibleboolean
Determine whether this function call is confirmedCall the function, returning an iterator over the results.boolean
markTailFunctionCalls
(int nameCode, int arity) Mark tail-recursive calls on stylesheet functions.optimize
(Optimizer opt, StaticContext env, ItemType contextItemType) Perform optimisation of an expression and its subexpressions.preEvaluate
(StaticContext env) Pre-evaluate a function at compile time.void
process
(XPathContext context) Process the function call in push modevoid
setConfirmed
(boolean conf) Set this function as confirmed (the function being called is known to exist) or notvoid
setFunction
(UserFunction compiledFunction, StaticContext env) Create the reference to the function to be called, and validate for consistencyvoid
setStaticType
(SequenceType type) Set the static typesimplify
(StaticContext env) Simplify the function calltypeCheck
(StaticContext env, ItemType contextItemType) Type-check the expression.Methods inherited from class net.sf.saxon.expr.FunctionCall
checkArgumentCount, getDisplayName, getFunctionNameCode, getNumberOfArguments, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionNameCode, simplifyArguments
Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation, typeError
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Constructor Details
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UserFunctionCall
public UserFunctionCall()
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Method Details
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setStaticType
Set the static type -
setFunction
Create the reference to the function to be called, and validate for consistency- Throws:
XPathException
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checkFunctionCall
public void checkFunctionCall(UserFunction compiledFunction, StaticContext env) throws XPathException Check the function call against the declared function signature- Throws:
XPathException
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getFunction
Get the function that is being called by this function call -
setConfirmed
public void setConfirmed(boolean conf) Set this function as confirmed (the function being called is known to exist) or not -
isConfirmed
public boolean isConfirmed()Determine whether this function call is confirmed -
getArguments
Get the arguments (the expressions supplied in the function call)- Overrides:
getArguments
in classFunctionCall
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checkArguments
Method called during the type checking phase- Specified by:
checkArguments
in classFunctionCall
- Throws:
XPathException
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preEvaluate
Pre-evaluate a function at compile time. This version of the method suppresses early evaluation by doing nothing.- Overrides:
preEvaluate
in classFunctionCall
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getItemType
Determine the data type of the expression, if possible- Specified by:
getItemType
in interfaceExpression
- Parameters:
th
-- Returns:
- Type.ITEM (meaning not known in advance)
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getIntrinsicDependencies
public int getIntrinsicDependencies()Description copied from class:ComputedExpression
Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".- 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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computeCardinality
public int computeCardinality()Determine the cardinality of the result- Specified by:
computeCardinality
in classComputedExpression
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simplify
Simplify the function call- Specified by:
simplify
in interfaceExpression
- Overrides:
simplify
in classFunctionCall
- Parameters:
env
- the static context- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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typeCheck
Description copied from class:FunctionCall
Type-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.- Specified by:
typeCheck
in interfaceExpression
- Overrides:
typeCheck
in classFunctionCall
- Parameters:
env
- the static context of the expressioncontextItemType
- the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set toType.ITEM_TYPE
- Returns:
- the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
- Throws:
XPathException
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optimize
public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException Description copied from class:FunctionCall
Perform optimisation of an expression and its subexpressions.This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.
- Specified by:
optimize
in interfaceExpression
- Overrides:
optimize
in classFunctionCall
- Parameters:
opt
- the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.env
- the static context of the expressioncontextItemType
- the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set toType.ITEM_TYPE
- Returns:
- the original expression, rewritten if appropriate to optimize execution
- Throws:
XPathException
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computeArgumentEvaluationModes
public void computeArgumentEvaluationModes() -
markTailFunctionCalls
public boolean markTailFunctionCalls(int nameCode, int arity) Mark tail-recursive calls on stylesheet functions. This marks the function call as tailRecursive if if is a call to the containing function, and in this case it also returns "true" to the caller to indicate that a tail call was found.- Overrides:
markTailFunctionCalls
in classComputedExpression
- Returns:
- true if a tail recursive call was found and if this call accounts for the whole of the value.
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getImplementationMethod
public int getImplementationMethod()Description copied from class:ComputedExpression
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 interfaceExpression
- Overrides:
getImplementationMethod
in classComputedExpression
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evaluateItem
Call the function, returning the value as an item. This method will be used only when the cardinality is zero or one. If the function is tail recursive, it returns an Object representing the arguments to the next (recursive) call- Specified by:
evaluateItem
in interfaceExpression
- Overrides:
evaluateItem
in classComputedExpression
- 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
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iterate
Call the function, returning an iterator over the results. (But if the function is tail recursive, it returns an iterator over the arguments of the recursive call)- Specified by:
iterate
in interfaceExpression
- Overrides:
iterate
in classComputedExpression
- 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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process
Process the function call in push mode- Specified by:
process
in interfaceExpression
- Overrides:
process
in classComputedExpression
- Parameters:
context
-- Throws:
XPathException
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dynamicCall
public ValueRepresentation dynamicCall(ValueRepresentation[] suppliedArguments, XPathContext context) throws XPathException Call the function dynamically. For this to be possible, the static arguments of the function call must have been set up as SuppliedParameterReference objects. The actual arguments are placed on the callee's stack, and the type conversion takes place "in situ".- Throws:
XPathException
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display
Description copied from interface:Expression
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Specified by:
display
in interfaceExpression
- Overrides:
display
in classFunctionCall
- Parameters:
level
- indentation level for this expressionout
- Output destinationconfig
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getInstructionInfo
Get diagnostic information about this expression- Specified by:
getInstructionInfo
in interfaceInstructionInfoProvider
- Overrides:
getInstructionInfo
in classComputedExpression
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