net.sf.saxon.expr.instruct

Class ValueOf

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.instruct.Instruction

net.sf.saxon.expr.instruct.SimpleNodeConstructor

net.sf.saxon.expr.instruct.ValueOf

All Implemented Interfaces:

TailCallReturner, IdentityComparable

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.

Field Summary

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

selectOp

Fields inherited from class net.sf.saxon.expr.Expression

EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD

Constructor Summary

Constructors

Constructor and Description
ValueOf(Expression select, boolean disable, boolean noNodeIfEmpty) Create a new ValueOf expression

Method Summary

Methods

Modifier and Type	Method and Description
void	checkPermittedContents(SchemaType parentType, 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	convertToCastAsString() Convert this value-of instruction to an expression that delivers the string-value of the resulting text node as an untyped atomic value.
Expression	copy() Copy an expression.
NodeInfo	evaluateItem(XPathContext context) Evaluate this expression, returning the resulting text node to the caller
void	export(ExpressionPresenter out) Diagnostic print of expression structure.
ExpressionCompiler	getExpressionCompiler() Return the compiler of the ValueOf expression
int	getInstructionNameCode() Get the name of this instruction for diagnostic and tracing purposes
int	getIntrinsicDependencies() Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.
ItemType	getItemType() Get the item type of the items returned by evaluating this instruction
int	getOptions() Test for any special options such as disable-output-escaping
boolean	isDisableOutputEscaping() Test whether disable-output-escaping was requested
boolean	isNoNodeIfEmpty()
boolean	isNumberingInstruction() Determine whether this is really an xsl:number instruction
void	localTypeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) Method to perform type-checking specific to the kind of instruction
TailCall	processLeavingTail(XPathContext context) Process this instruction
void	processValue(CharSequence value, XPathContext context) Process the value of the node, to create the new node.
void	setIsNumberingInstruction() Indicate that this is really an xsl:nunber instruction

Methods inherited from class net.sf.saxon.expr.instruct.SimpleNodeConstructor

checkContent, computeSpecialProperties, createsNewNodes, evaluateNodeName, getSelect, getStreamingAdjunct, iterate, operands, optimize, promoteChildren, setSelect, typeCheck

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

assembleParams, assembleTunnelParams, dynamicError, evaluateAsString, getConstructType, getExpressionName, getImplementationMethod, getInstructionName, getNetCost, getSourceLocator, isXSLT, main, process, toStreamingPattern

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

addToPathMap, adoptChildExpression, checkedOperands, checkForUpdatingSubexpressions, clearStreamabilityData, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getCost, getDependencies, getEvaluationMethod, getHostLanguage, getIntegerBounds, getLocation, getObjectName, getPackageData, getParentExpression, getPosture, getPostureAndSweepIfKnown, getProperties, getProperty, getRetainedStaticContext, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStreamability, getSweep, getSystemId, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isCallOnSystemFunction, isIdentical, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, makeStreamingAdjunct, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, optimizeForType, promote, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setFiltered, setFlattened, setLocation, setParentExpression, setPostureAndSweep, setRetainedStaticContext, setRetainedStaticContextLocally, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, toShortString, toString, typeCheckChildren, typeError, unordered

Methods inherited from class java.lang.Object

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

Constructor Detail

ValueOf

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

Create a new ValueOf expression

Parameters:

select - the select expression

disable - true if disable-output-escaping is in force

noNodeIfEmpty - true if the instruction is to return () if the select expression is (), false if it is to return an empty text node

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

Returns:

true if this derives from xsl:number

isNoNodeIfEmpty

public boolean isNoNodeIfEmpty()

getInstructionNameCode

public int getInstructionNameCode()

Get the name of this instruction for diagnostic and tracing purposes

Overrides:

getInstructionNameCode in class Instruction

Returns:

the namecode of the instruction name

getOptions

public int getOptions()

Test for any special options such as disable-output-escaping

Returns:

any special options

isDisableOutputEscaping

public boolean isDisableOutputEscaping()

Test whether disable-output-escaping was requested

Returns:

true if disable-output-escaping was requested

getItemType

public ItemType getItemType()

Description copied from class: Instruction

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

Overrides:

getItemType in class Instruction

Returns:

the static item type of the instruction

computeCardinality

public int computeCardinality()

Description copied from class: SimpleNodeConstructor

Get the cardinality of the sequence returned by evaluating this instruction

Overrides:

computeCardinality in class SimpleNodeConstructor

Returns:

the static cardinality

localTypeCheck

public void localTypeCheck(ExpressionVisitor visitor,
                  ContextItemStaticInfo contextItemType)

Description copied from class: SimpleNodeConstructor

Method to perform type-checking specific to the kind of instruction

Specified by:

localTypeCheck in class SimpleNodeConstructor

Parameters:

visitor - an expression visitor

contextItemType - the static type of the context item

getIntrinsicDependencies

public int getIntrinsicDependencies()

Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".

Overrides:

getIntrinsicDependencies in class Expression

Returns:

a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

copy

public Expression copy()

Copy an expression. This makes a deep copy.

Specified by:

copy in class Expression

Returns:

the copy of the original expression

checkPermittedContents

public void checkPermittedContents(SchemaType parentType,
                          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 class Expression

Parameters:

parentType - The schema type

whole - 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

convertToCastAsString

public Expression convertToCastAsString()

Convert this value-of instruction to an expression that delivers the string-value of the resulting text node as an untyped atomic value.

Returns:

the converted expression

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws XPathException

Process this instruction

Specified by:

processLeavingTail in interface TailCallReturner

Overrides:

processLeavingTail in class SimpleNodeConstructor

Parameters:

context - the dynamic context of the transformation

Returns:

a TailCall to be executed by the caller, always null for this instruction

Throws:

XPathException - if a dynamic error occurs during the evaluation of the instruction

processValue

public void processValue(CharSequence value,
                XPathContext context)
                  throws XPathException

Process the value of the node, to create the new node.

Specified by:

processValue in class SimpleNodeConstructor

Parameters:

value - the string value of the new node

context - the dynamic evaluation context

Throws:

XPathException

evaluateItem

public NodeInfo evaluateItem(XPathContext context)
                      throws XPathException

Evaluate this expression, returning the resulting text node to the caller

Overrides:

evaluateItem in class SimpleNodeConstructor

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

getExpressionCompiler

public ExpressionCompiler getExpressionCompiler()

Return the compiler of the ValueOf expression

Overrides:

getExpressionCompiler in class Expression

Returns:

the relevant ExpressionCompiler

export

public void export(ExpressionPresenter out)

Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

Specified by:

export in class Expression

Parameters:

out - the expression presenter used to display the structure