Package net.sf.saxon.instruct
Class ValueOf
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.instruct.Instruction
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- net.sf.saxon.instruct.SimpleNodeConstructor
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- net.sf.saxon.instruct.ValueOf
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,LocationProvider
,SaxonLocator
,EvaluableItem
,SequenceIterable
,TailCallReturner
,InstructionInfo
,org.xml.sax.Locator
public final class ValueOf extends SimpleNodeConstructor
An xsl:value-of element in the stylesheet.
The xsl:value-of element takes attributes:- a mandatory attribute select="expression". This must be a valid String expression
- an optional disable-output-escaping attribute, value "yes" or "no"
- an optional separator attribute. This is handled at compile-time: if the separator attribute is present, the select expression passed in here will be a call to the string-join() function.
- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class net.sf.saxon.instruct.SimpleNodeConstructor
select
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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 ValueOf(Expression select, boolean disable, boolean noNodeIfEmpty)
Create a new ValueOf expression
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
checkPermittedContents(SchemaType parentType, StaticContext env, boolean whole)
Check statically that the results of the expression are capable of constructing the content of a given schema type.int
computeCardinality()
Get the cardinality of the sequence returned by evaluating this instructionExpression
convertToStringJoin(StaticContext env)
Convert this value-of instruction to an expression that delivers the string-value of the resulting text node.Expression
copy()
Copy an expression.Item
evaluateItem(XPathContext context)
Evaluate this expression, returning the resulting text node to the callervoid
explain(ExpressionPresenter out)
Diagnostic print of expression structure.int
getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposesItemType
getItemType(TypeHierarchy th)
Get the item type of the items returned by evaluating this instructionint
getOptions()
Test for any special options such as disable-output-escapingboolean
isDisableOutputEscaping()
Test whether disable-output-escaping was requestedboolean
isNumberingInstruction()
Determine whether this is really an xsl:number instructionvoid
localTypeCheck(ExpressionVisitor visitor, ItemType contextItemType)
Method to perform type-checking specific to the kind of instructionTailCall
processLeavingTail(XPathContext context)
Process this instruction, sending the resulting text node to the current output destinationprotected void
promoteInst(PromotionOffer offer)
Offer promotion for subexpressions.void
setIsNumberingInstruction()
Indicate that this is really an xsl:nunber instruction-
Methods inherited from class net.sf.saxon.instruct.SimpleNodeConstructor
checkContent, computeSpecialProperties, createsNewNodes, evaluateNameCode, expandChildren, getSelect, iterate, iterateSubExpressions, optimize, replaceSubExpression, setSelect, simplify, typeCheck
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Methods inherited from class net.sf.saxon.instruct.Instruction
assembleParams, assembleTunnelParams, dynamicError, evaluateAsString, getConstructType, getImplementationMethod, getSourceLocator, isXSLT, process, promote
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Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getContainer, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterateEvents, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toString, typeError
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Constructor Detail
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ValueOf
public ValueOf(Expression select, boolean disable, boolean noNodeIfEmpty)
Create a new ValueOf expression- Parameters:
select
- the select expressiondisable
- true if disable-output-escaping is in forcenoNodeIfEmpty
- true if the instruction is to return () if the select expression is (), false if it is to return an empty text node
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Method Detail
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setIsNumberingInstruction
public void setIsNumberingInstruction()
Indicate that this is really an xsl:nunber instruction
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isNumberingInstruction
public boolean isNumberingInstruction()
Determine whether this is really an xsl:number instruction- Returns:
- true if this derives from xsl:number
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getInstructionNameCode
public int getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposes- Overrides:
getInstructionNameCode
in classInstruction
- Returns:
- the namecode of the instruction name
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promoteInst
protected void promoteInst(PromotionOffer offer) throws XPathException
Offer promotion for subexpressions. The offer will be accepted if the subexpression is not dependent on the factors (e.g. the context item) identified in the PromotionOffer. By default the offer is not accepted - this is appropriate in the case of simple expressions such as constant values and variable references where promotion would give no performance advantage. This method is always called at compile time.- Overrides:
promoteInst
in classSimpleNodeConstructor
- 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- Throws:
XPathException
- if any error is detected
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getOptions
public int getOptions()
Test for any special options such as disable-output-escaping- Returns:
- any special options
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isDisableOutputEscaping
public boolean isDisableOutputEscaping()
Test whether disable-output-escaping was requested- Returns:
- true if disable-output-escaping was requested
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getItemType
public ItemType getItemType(TypeHierarchy th)
Description copied from class:Instruction
Get the item type of the items returned by evaluating this instruction- Overrides:
getItemType
in classInstruction
- Parameters:
th
- the type hierarchy cache- Returns:
- the static item type of the instruction
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computeCardinality
public int computeCardinality()
Description copied from class:SimpleNodeConstructor
Get the cardinality of the sequence returned by evaluating this instruction- Overrides:
computeCardinality
in classSimpleNodeConstructor
- Returns:
- the static cardinality
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localTypeCheck
public void localTypeCheck(ExpressionVisitor visitor, ItemType contextItemType)
Description copied from class:SimpleNodeConstructor
Method to perform type-checking specific to the kind of instruction- Specified by:
localTypeCheck
in classSimpleNodeConstructor
- Parameters:
visitor
- an expression visitorcontextItemType
- the static type of the context item
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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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checkPermittedContents
public void checkPermittedContents(SchemaType parentType, StaticContext env, boolean whole) throws XPathException
Check statically that the results of the expression are capable of constructing the content of a given schema type.- Overrides:
checkPermittedContents
in classExpression
- Parameters:
parentType
- The schema typeenv
- the static contextwhole
- true if this expression is to account for the whole value of the type- Throws:
XPathException
- if the expression doesn't match the required content type
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convertToStringJoin
public Expression convertToStringJoin(StaticContext env)
Convert this value-of instruction to an expression that delivers the string-value of the resulting text node. This will often be a call on the string-join function.- Parameters:
env
- the static evaluation context- Returns:
- the converted expression
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processLeavingTail
public TailCall processLeavingTail(XPathContext context) throws XPathException
Process this instruction, sending the resulting text node to the current output destination- Specified by:
processLeavingTail
in interfaceTailCallReturner
- Specified by:
processLeavingTail
in classInstruction
- Parameters:
context
- the dynamic evaluation context- Returns:
- Always returns null
- Throws:
XPathException
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evaluateItem
public Item evaluateItem(XPathContext context) throws XPathException
Evaluate this expression, returning the resulting text node to the caller- Specified by:
evaluateItem
in interfaceEvaluableItem
- Overrides:
evaluateItem
in classSimpleNodeConstructor
- Parameters:
context
- the dynamic evaluation context- Returns:
- the parentless text node that results from evaluating this instruction, or null to represent an empty sequence
- Throws:
XPathException
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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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