net.sf.saxon.instruct
Class ValueOf

java.lang.Object
  extended bynet.sf.saxon.expr.ComputedExpression
      extended bynet.sf.saxon.instruct.Instruction
          extended bynet.sf.saxon.instruct.SimpleNodeConstructor
              extended bynet.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:

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
 Expression convertToStringJoin(StaticContext env)
          Convert this value-of instruction to an expression that delivers the string-value of the resulting text node.
 void display(int level, java.io.PrintStream out, Configuration config)
          Display this instruction as an expression, for diagnostics
 Item evaluateItem(XPathContext context)
          Evaluate this expression, returning the resulting text node to the caller
 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
 boolean isNumberingInstruction()
          Determine whether this is really an xsl:number instruction
 void localTypeCheck(StaticContext env, ItemType contextItemType)
           
 TailCall processLeavingTail(XPathContext context)
          Process this instruction, sending the resulting text node to the current output destination
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, replaceSubExpression, 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, effectiveBooleanValue, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation, 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


isNumberingInstruction

public boolean isNumberingInstruction()
Determine whether this is really an xsl:number 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

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.


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 interface TailCallReturner
Specified by:
processLeavingTail in class Instruction
Parameters:
context -
Returns:
Always returns null
Throws:
XPathException

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException
Evaluate this expression, returning the resulting text node to the caller

Specified by:
evaluateItem in interface Expression
Overrides:
evaluateItem in class SimpleNodeConstructor
Parameters:
context -
Returns:
the parentless text node that results from evaluating this instruction, or null to represent an empty sequence
Throws:
XPathException

display

public void display(int level,
                    java.io.PrintStream out,
                    Configuration config)
Display this instruction as an expression, for diagnostics

Specified by:
display in interface Expression
Overrides:
display in class SimpleNodeConstructor