Class FunctionCall
- 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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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,LocationProvider
,SaxonLocator
,InstructionInfo
,org.xml.sax.Locator
- Direct Known Subclasses:
IntegratedFunctionCall
,SystemFunction
,UserFunctionCall
,XPathFunctionCall
public abstract class FunctionCall extends Expression
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.Expression
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_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 PathMap.PathMapNodeSet
addExternalFunctionCallToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodes)
Add a representation of this expression to a PathMap.protected int
checkArgumentCount(int min, int max)
Check number of arguments.protected abstract void
checkArguments(ExpressionVisitor visitor)
Method supplied by each class of function to check arguments during parsing, when all the argument expressions have been readboolean
equals(java.lang.Object o)
Determine whether two expressions are equivalentvoid
explain(ExpressionPresenter out)
Diagnostic print of expression structure.Expression[]
getArguments()
Get the expressions supplied as actual arguments to the functionjava.lang.String
getDisplayName()
Get the name of the function for display in messagesjava.lang.String
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.StructuredQName
getFunctionName()
Get the qualified of the function being calledint
getNumberOfArguments()
Determine the number of actual arguments supplied in the function callint
hashCode()
Get hashCode in support of equals() methodjava.util.Iterator<Expression>
iterateSubExpressions()
Get the immediate subexpressions of this expressionExpression
optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions.Expression
preEvaluate(ExpressionVisitor visitor)
Pre-evaluate a function at compile time.Expression
promote(PromotionOffer offer, Expression parent)
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
setFunctionName(StructuredQName name)
Set the name of the function being calledExpression
simplify(ExpressionVisitor visitor)
Simplify the function call.protected Expression
simplifyArguments(ExpressionVisitor visitor)
Simplify the arguments of the function.java.lang.String
toString()
The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath.Expression
typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)
Type-check the expression.-
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeCardinality, computeDependencies, computeSpecialProperties, computeStaticProperties, copy, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getImplementationMethod, getIntegerBounds, getIntrinsicDependencies, getItemType, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
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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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setFunctionName
public final void setFunctionName(StructuredQName name)
Set the name of the function being called- Parameters:
name
- the name of the function
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getFunctionName
public StructuredQName getFunctionName()
Get the qualified of the function being called- Returns:
- the qualified name
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getNumberOfArguments
public final int getNumberOfArguments()
Determine the number of actual arguments supplied in the function call- Returns:
- the arity (the number of arguments)
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setArguments
public void setArguments(Expression[] args)
Method called by the expression parser when all arguments have been supplied- Parameters:
args
- the expressions contained in the argument list of the function call
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getArguments
public Expression[] getArguments()
Get the expressions supplied as actual arguments to the function- Returns:
- the array of expressions supplied in the argument list of the function call
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simplify
public Expression simplify(ExpressionVisitor visitor) 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.- Overrides:
simplify
in classExpression
- Parameters:
visitor
- an expression visitor- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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simplifyArguments
protected final Expression simplifyArguments(ExpressionVisitor visitor) throws XPathException
Simplify the arguments of the function. Called from the simplify() method of each function.- Parameters:
visitor
- an expression visitor- Returns:
- the result of simplifying the arguments of the expression
- Throws:
XPathException
- if an error occurs
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType 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.- Overrides:
typeCheck
in classExpression
- Parameters:
visitor
- an expression visitorcontextItemType
- 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
- if an error is discovered during this phase (typically a type error)
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optimize
public Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType 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.
- Overrides:
optimize
in classExpression
- Parameters:
visitor
- an expression visitorcontextItemType
- 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
- if an error is discovered during this phase (typically a type error)
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preEvaluate
public Expression preEvaluate(ExpressionVisitor visitor) 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.- Parameters:
visitor
- an expression visitor- Returns:
- the result of the early evaluation, or the original expression, or potentially a simplified expression
- Throws:
XPathException
- if evaluation fails
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promote
public Expression promote(PromotionOffer offer, Expression parent) throws XPathException
Promote this expression if possible- Overrides:
promote
in classExpression
- 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 expressionparent
- the containing expression in the expression tree- 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(ExpressionVisitor visitor) throws XPathException
Method supplied by each class of function to check arguments during parsing, when all the argument expressions have been read- Parameters:
visitor
- the expression visitor- Throws:
XPathException
- if the arguments are incorrect
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checkArgumentCount
protected int checkArgumentCount(int min, int max) 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<Expression> iterateSubExpressions()
Get the immediate subexpressions of this expression- Overrides:
iterateSubExpressions
in classExpression
- 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- Overrides:
replaceSubExpression
in classExpression
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression- Returns:
- true if the original subexpression is found
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addExternalFunctionCallToPathMap
public PathMap.PathMapNodeSet addExternalFunctionCallToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodes)
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.
- Parameters:
pathMap
- the PathMap to which the expression should be addedpathMapNodes
- the node in the PathMap representing the focus at the point where this expression is called. Set to null if this expression appears at the top level, in which case the expression, if it is registered in the path map at all, must create a new path map root.- 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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getExpressionName
public final java.lang.String getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.- Overrides:
getExpressionName
in classExpression
- Returns:
- a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.
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getDisplayName
public final java.lang.String getDisplayName()
Get the name of the function for display in messages- Returns:
- the name of the function as a lexical QName
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toString
public java.lang.String toString()
The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath. In the case of XSLT instructions, the toString() method gives an abstracted view of the syntax- Overrides:
toString
in classExpression
- Returns:
- a representation of the expression as a string
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explain
public void explain(ExpressionPresenter out)
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Specified by:
explain
in classExpression
- Parameters:
out
- the expression presenter used to display the structure
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equals
public boolean equals(java.lang.Object o)
Determine whether two expressions are equivalent- Overrides:
equals
in classjava.lang.Object
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hashCode
public int hashCode()
Get hashCode in support of equals() method- Overrides:
hashCode
in classjava.lang.Object
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