net.sf.saxon.instruct
Class ValueOf

java.lang.Object
  net.sf.saxon.expr.ComputedExpression
      net.sf.saxon.instruct.Instruction
          net.sf.saxon.instruct.SimpleNodeConstructor
              net.sf.saxon.instruct.ValueOf

All Implemented Interfaces:

Container, Expression, InstructionInfoProvider, java.io.Serializable, javax.xml.transform.SourceLocator, TailCallReturner

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

Field Summary

Fields inherited from class net.sf.saxon.instruct.SimpleNodeConstructor

select

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

Constructor Summary

ValueOf(Expression select, boolean disable, boolean noNodeIfEmpty)

Method Summary

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 instruction
void	display(int level, NamePool pool, java.io.PrintStream out) Display this instruction as an expression, for diagnostics
Item	evaluateItem(XPathContext context) Evaluate as an expression.
int	getInstructionNameCode() Get the name of this instruction for diagnostic and tracing purposes
ItemType	getItemType(TypeHierarchy th) Get the item type of the items returned by evaluating this instruction
void	localTypeCheck(StaticContext env, ItemType contextItemType)
TailCall	processLeavingTail(XPathContext context) ProcessLeavingTail: called to do the real work of this instruction.
protected 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, setSelect, simplify, typeCheck

Methods inherited from class net.sf.saxon.instruct.Instruction

appendItem, assembleParams, assembleTunnelParams, dynamicError, evaluateAsString, getImplementationMethod, getInstructionInfo, getSourceLocator, isXSLT, process, promote

Methods inherited from class net.sf.saxon.expr.ComputedExpression

adoptChildExpression, computeDependencies, computeStaticProperties, doPromotion, dynamicError, dynamicError, effectiveBooleanValue, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, resetStaticProperties, setLocationId, setParentExpression, suppressValidation, typeError, typeError

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface javax.xml.transform.SourceLocator

getColumnNumber, getLineNumber, getPublicId, getSystemId

Constructor Detail

ValueOf

public ValueOf(Expression select,
               boolean disable,
               boolean noNodeIfEmpty)

Method Detail

setIsNumberingInstruction

public void setIsNumberingInstruction()

Indicate that this is really an xsl:nunber instruction

getInstructionNameCode

public int getInstructionNameCode()

Get the name of this instruction for diagnostic and tracing purposes

Overrides:

getInstructionNameCode in class Instruction

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 class SimpleNodeConstructor

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

getItemType

public ItemType getItemType(TypeHierarchy th)

Description copied from class: Instruction

Get the item type of the items returned by evaluating this instruction

Specified by:

getItemType in interface Expression

Overrides:

getItemType in class Instruction

Parameters:

th -

Returns:

the static item type of the instruction

computeCardinality

public int computeCardinality()

Description copied from class: Instruction

Get the cardinality of the sequence returned by evaluating this instruction

Overrides:

computeCardinality in class Instruction

Returns:

the static cardinality

localTypeCheck

public void localTypeCheck(StaticContext env,
                           ItemType contextItemType)

Specified by:

localTypeCheck in class SimpleNodeConstructor

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.

Specified by:

checkPermittedContents in interface Expression

Overrides:

checkPermittedContents in class ComputedExpression

Parameters:

parentType - The schema type

env - the static context

whole -

Throws:

XPathException - if the expression doesn't match the required content type

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws XPathException

Description copied from class: Instruction

ProcessLeavingTail: called to do the real work of this instruction. This method must be implemented in each subclass. The results of the instruction are written to the current Receiver, which can be obtained via the Controller.

Specified by:

processLeavingTail in interface TailCallReturner

Specified by:

processLeavingTail in class Instruction

Parameters:

context - The dynamic context of the transformation, giving access to the current node, the current variables, etc.

Returns:

null if the instruction has completed execution; or a TailCall indicating a function call or template call that is delegated to the caller, to be made after the stack has been unwound so as to save stack space.

Throws:

XPathException

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Description copied from class: SimpleNodeConstructor

Evaluate as an expression. We rely on the fact that when these instructions are generated by XQuery, there will always be a valueExpression to evaluate the content

Specified by:

evaluateItem in interface Expression

Overrides:

evaluateItem in class SimpleNodeConstructor

Throws:

XPathException

display

public void display(int level,
                    NamePool pool,
                    java.io.PrintStream out)

Display this instruction as an expression, for diagnostics

Specified by:

display in interface Expression

Overrides:

display in class SimpleNodeConstructor