Package net.sf.saxon.expr
Class FunctionCall
- 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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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,Container
,Expression
,InstructionInfoProvider
- Direct Known Subclasses:
ExtensionFunctionCall
,SystemFunction
,UserFunctionCall
,XPathFunctionCall
public abstract class FunctionCall extends ComputedExpression
Abstract superclass for calls to system-defined and user-defined functions- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description protected Expression[]
argument
The array of expressions representing the actual parameters to the function call-
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 FunctionCall()
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected int
checkArgumentCount(int min, int max, StaticContext env)
Check number of arguments.protected abstract void
checkArguments(StaticContext env)
Method supplied by each class of function to check arguments during parsing, when all the argument expressions have been readvoid
display(int level, java.io.PrintStream out, Configuration config)
Diagnostic print of expression structure.Expression[]
getArguments()
Get the expressions supplied as actual arguments to the functionjava.lang.String
getDisplayName(NamePool pool)
Diagnostic print of expression structureint
getFunctionNameCode()
Get the name code of the function being calledint
getNumberOfArguments()
Determine the number of actual arguments supplied in the function calljava.util.Iterator
iterateSubExpressions()
Get the immediate subexpressions of this expressionExpression
optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.Expression
preEvaluate(StaticContext env)
Pre-evaluate a function at compile time.Expression
promote(PromotionOffer offer)
Promote this expression if possibleboolean
replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpressionvoid
setArguments(Expression[] args)
Method called by the expression parser when all arguments have been suppliedvoid
setFunctionNameCode(int nc)
Set the name code of the function being calledExpression
simplify(StaticContext env)
Simplify the function call.protected Expression
simplifyArguments(StaticContext env)
Simplify the arguments of the function.Expression
typeCheck(StaticContext env, ItemType contextItemType)
Type-check the expression.-
Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, checkPermittedContents, computeCardinality, computeDependencies, computeSpecialProperties, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation, typeError
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface net.sf.saxon.expr.Expression
getItemType
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Field Detail
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argument
protected Expression[] argument
The array of expressions representing the actual parameters to the function call
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Method Detail
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setFunctionNameCode
public final void setFunctionNameCode(int nc)
Set the name code of the function being called
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getFunctionNameCode
public final int getFunctionNameCode()
Get the name code of the function being called- Returns:
- the name code as recorded in the name pool
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getNumberOfArguments
public final int getNumberOfArguments()
Determine the number of actual arguments supplied in the function call
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setArguments
public void setArguments(Expression[] args)
Method called by the expression parser when all arguments have been supplied
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getArguments
public Expression[] getArguments()
Get the expressions supplied as actual arguments to the function
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simplify
public Expression simplify(StaticContext env) throws XPathException
Simplify the function call. Default method is to simplify each of the supplied arguments and evaluate the function if all are now known.- Specified by:
simplify
in interfaceExpression
- Overrides:
simplify
in classComputedExpression
- Parameters:
env
- the static context- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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simplifyArguments
protected final Expression simplifyArguments(StaticContext env) throws XPathException
Simplify the arguments of the function. Called from the simplify() method of each function.- Returns:
- the result of simplifying the arguments of the expression
- Throws:
XPathException
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typeCheck
public Expression typeCheck(StaticContext env, ItemType contextItemType) throws XPathException
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.- 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:
StaticError
- if an error is discovered during this phase (typically a type error)XPathException
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optimize
public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException
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.
- 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:
StaticError
- if an error is discovered during this phase (typically a type error)XPathException
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preEvaluate
public Expression preEvaluate(StaticContext env) throws XPathException
Pre-evaluate a function at compile time. Functions that do not allow pre-evaluation, or that need access to context information, can override this method.- Throws:
XPathException
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promote
public Expression promote(PromotionOffer offer) throws XPathException
Promote this expression if possible- Specified by:
promote
in interfaceExpression
- Overrides:
promote
in classComputedExpression
- Parameters:
offer
- details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression- Returns:
- if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression
- Throws:
XPathException
- if any error is detected
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checkArguments
protected abstract void checkArguments(StaticContext env) throws XPathException
Method supplied by each class of function to check arguments during parsing, when all the argument expressions have been read- Throws:
XPathException
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checkArgumentCount
protected int checkArgumentCount(int min, int max, StaticContext env) throws XPathException
Check number of arguments.
A convenience routine for use in subclasses.- Parameters:
min
- the minimum number of arguments allowedmax
- the maximum number of arguments allowed- Returns:
- the actual number of arguments
- Throws:
XPathException
- if the number of arguments is out of range
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iterateSubExpressions
public java.util.Iterator iterateSubExpressions()
Get the immediate subexpressions of this expression- Specified by:
iterateSubExpressions
in interfaceExpression
- Overrides:
iterateSubExpressions
in classComputedExpression
- Returns:
- an iterator containing the sub-expressions of this expression
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replaceSubExpression
public boolean replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpression- Specified by:
replaceSubExpression
in interfaceContainer
- Overrides:
replaceSubExpression
in classComputedExpression
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression- Returns:
- true if the original subexpression is found
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getDisplayName
public final java.lang.String getDisplayName(NamePool pool)
Diagnostic print of expression structure
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display
public void display(int level, java.io.PrintStream out, Configuration config)
Description copied from interface:Expression
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Parameters:
level
- indentation level for this expressionout
- Output destination
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