Package net.sf.saxon.functions
Class Evaluate
- 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.functions.SystemFunction
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- net.sf.saxon.functions.Evaluate
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,Container
,Expression
,InstructionInfoProvider
public class Evaluate extends SystemFunction
This class implements the saxon:evaluate(), saxon:expression(), and saxon:eval() extension functions, which are specially-recognized by the system because they need access to parts of the static context- See Also:
- Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
Evaluate.PreparedExpression
Inner class PreparedExpression represents a compiled XPath expression together with the standard variables $p1 ..
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Field Summary
Fields Modifier and Type Field Description (package private) InstructionDetails
details
static int
EVAL
static int
EVALUATE
static int
EVALUATE_NODE
static int
EXPRESSION
(package private) IndependentContext
staticContext
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Fields inherited from class net.sf.saxon.functions.SystemFunction
operation
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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 Evaluate()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
checkArguments(StaticContext env)
Method supplied by each class of function to check arguments during parsing, when all the argument expressions have been readItem
evaluateItem(XPathContext c)
Evaluate in a general contextint
getIntrinsicDependencies()
Determine the dependenciesprotected SequenceType
getRequiredType(int arg)
Get the required type of the nth argumentSequenceIterator
iterate(XPathContext c)
Iterate over the results of the functionExpression
preEvaluate(StaticContext env)
preEvaluate: for saxon:expression, if the expression is known at compile time, then it is compiled at compile time.-
Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, computeCardinality, computeSpecialProperties, display, getDetails, getErrorCodeForTypeErrors, getItemType, main, makeSystemFunction, setDetails, useContextItemAsDefault
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Methods inherited from class net.sf.saxon.expr.FunctionCall
checkArgumentCount, 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, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, 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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Field Detail
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staticContext
IndependentContext staticContext
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details
InstructionDetails details
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EVALUATE
public static final int EVALUATE
- See Also:
- Constant Field Values
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EXPRESSION
public static final int EXPRESSION
- See Also:
- Constant Field Values
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EVAL
public static final int EVAL
- See Also:
- Constant Field Values
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EVALUATE_NODE
public static final int EVALUATE_NODE
- See Also:
- Constant Field Values
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Method Detail
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getRequiredType
protected SequenceType getRequiredType(int arg)
Get the required type of the nth argument- Overrides:
getRequiredType
in classSystemFunction
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checkArguments
public 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- Overrides:
checkArguments
in classSystemFunction
- Throws:
XPathException
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preEvaluate
public Expression preEvaluate(StaticContext env) throws XPathException
preEvaluate: for saxon:expression, if the expression is known at compile time, then it is compiled at compile time. In other cases this method suppresses compile-time evaluation by doing nothing (because the value of the expression depends on the runtime context).- Overrides:
preEvaluate
in classFunctionCall
- Throws:
XPathException
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evaluateItem
public Item evaluateItem(XPathContext c) throws XPathException
Evaluate in a general context- 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
public SequenceIterator iterate(XPathContext c) throws XPathException
Iterate over the results of the function- 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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getIntrinsicDependencies
public int getIntrinsicDependencies()
Determine the 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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