net.sf.saxon.instruct

Class FixedAttribute

Implemented Interfaces:
SourceLocator, EvaluableItem, InstructionInfoProvider, SequenceIterable, Serializable, SourceLocator, TailCallReturner

public final class FixedAttribute
extends SimpleNodeConstructor

An instruction derived from an xsl:attribute element in stylesheet, or from an attribute constructor in XQuery. This version deals only with attributes whose name is known at compile time. It is also used for attributes of literal result elements. The value of the attribute is in general computed at run-time.

Field Summary

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

select

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD, locationId, staticProperties

Constructor Summary

FixedAttribute(int nameCode, int validationAction, SimpleType schemaType, int annotation)
Construct an Attribute instruction

Method Summary

void
checkPermittedContents(SchemaType parentType, StaticContext env, boolean whole)
Check that any elements and attributes constructed or returned by this expression are acceptable in the content model of a given complex type.
Expression
copy()
Copy an expression.
Item
evaluateItem(XPathContext context)
Evaluate as an expression.
int
evaluateNameCode(XPathContext context)
Run-time method to compute the name of the node being constructed.
void
explain(ExpressionPresenter out)
Diagnostic print of expression structure.
int
getAttributeNameCode()
Get the name pool name code of the attribute to be constructed
int
getCardinality()
Determine the static cardinality of the expression.
InstructionInfo
getInstructionInfo()
Get InstructionInfo for this expression
int
getInstructionNameCode()
Get the name of this instruction (return 'xsl:attribute')
ItemType
getItemType(TypeHierarchy th)
Get the item type of the items returned by evaluating this instruction
int
getValidationAction()
Get the validation action requested
void
localTypeCheck(ExpressionVisitor visitor, ItemType contextItemType)
Method to perform type-checking specific to the kind of instruction
TailCall
processLeavingTail(XPathContext context)
Process this instruction
void
setNoSpecialChars()
Indicate that the attribute value contains no special characters that might need escaping
void
setRejectDuplicates()
Indicate that two attributes with the same name are not acceptable.
void
setSelect(Expression select, Configuration config)
Set the expression defining the value of the attribute.

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

checkContent, computeCardinality, computeSpecialProperties, createsNewNodes, evaluateItem, evaluateNameCode, expandChildren, getSelect, iterate, iterateSubExpressions, localTypeCheck, optimize, promoteInst, replaceSubExpression, setSelect, simplify, typeCheck

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

assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, createsNewNodes, dynamicError, evaluateAsString, evaluateItem, getImplementationMethod, getInstructionInfo, getInstructionNameCode, getItemType, getSourceLocator, isXSLT, iterate, process, processLeavingTail, promote, promoteInst, simplify

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

addToPathMap, adoptChildExpression, checkPermittedContents, computeCardinality, computeDependencies, computeSpecialProperties, computeStaticProperties, copy, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, explain, explain, findParentOf, getCardinality, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getItemType, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterate, iterateEvents, iterateSubExpressions, markTailFunctionCalls, optimize, process, promote, replaceSubExpression, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, simplify, staticTypeCheck, suppressValidation, toString, typeCheck, typeError

Constructor Details

FixedAttribute

public FixedAttribute(int nameCode,
                      int validationAction,
                      SimpleType schemaType,
                      int annotation)
Construct an Attribute instruction
Parameters:
nameCode - Represents the attribute name
validationAction - the validation required, for example strict or lax
schemaType - the schema type against which validation is required, null if not applicable
annotation - Integer code identifying the type named in the type attribute of the instruction - zero if the attribute was not present

Method Details

checkPermittedContents

public void checkPermittedContents(SchemaType parentType,
                                   StaticContext env,
                                   boolean whole)
            throws XPathException
Check that any elements and attributes constructed or returned by this expression are acceptable in the content model of a given complex type. It's always OK to say yes, since the check will be repeated at run-time. The process of checking element and attribute constructors against the content model of a complex type also registers the type of content expected of those constructors, so the static validation can continue recursively.
Overrides:
checkPermittedContents in interface Expression

copy

public Expression copy()
Copy an expression. This makes a deep copy.
Overrides:
copy in interface Expression
Returns:
the copy of the original expression

evaluateItem

public Item evaluateItem(XPathContext context)
            throws XPathException
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 EvaluableItem
Overrides:
evaluateItem in interface SimpleNodeConstructor

evaluateNameCode

public int evaluateNameCode(XPathContext context)
Run-time method to compute the name of the node being constructed. This is overridden for nodes that have a name. The default implementation returns -1, which is suitable for unnamed nodes such as comments
Overrides:
evaluateNameCode in interface SimpleNodeConstructor
Parameters:
context - the XPath dynamic evaluation context
Returns:
the name pool nameCode identifying the name of the constructed node

explain

public void explain(ExpressionPresenter out)
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
Overrides:
explain in interface Expression

getAttributeNameCode

public int getAttributeNameCode()
Get the name pool name code of the attribute to be constructed
Returns:
the attribute's name code

getCardinality

public int getCardinality()
Determine the static cardinality of the expression. This establishes how many items there will be in the result of the expression, at compile time (i.e., without actually evaluating the result.
Overrides:
getCardinality in interface Expression
Returns:
one of the values Cardinality.ONE_OR_MORE, Cardinality.ZERO_OR_MORE, Cardinality.EXACTLY_ONE, Cardinality.ZERO_OR_ONE, Cardinality.EMPTY. This default implementation returns ZERO_OR_MORE (which effectively gives no information).

getInstructionInfo

public InstructionInfo getInstructionInfo()
Get InstructionInfo for this expression
Specified by:
getInstructionInfo in interface InstructionInfoProvider
Overrides:
getInstructionInfo in interface Instruction

getInstructionNameCode

public int getInstructionNameCode()
Get the name of this instruction (return 'xsl:attribute')
Overrides:
getInstructionNameCode in interface Instruction

getItemType

public ItemType getItemType(TypeHierarchy th)
Get the item type of the items returned by evaluating this instruction
Overrides:
getItemType in interface Instruction
Parameters:
th - the type hierarchy cache
Returns:
the static item type of the instruction

getValidationAction

public int getValidationAction()
Get the validation action requested
Returns:
the validation action, for example strict or lax

localTypeCheck

public void localTypeCheck(ExpressionVisitor visitor,
                           ItemType contextItemType)
Method to perform type-checking specific to the kind of instruction
Overrides:
localTypeCheck in interface SimpleNodeConstructor
Parameters:
visitor - an expression visitor
contextItemType - the static type of the context item

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
            throws XPathException
Process this instruction
Specified by:
processLeavingTail in interface TailCallReturner
Overrides:
processLeavingTail in interface Instruction
Parameters:
context - the dynamic context of the transformation
Returns:
a TailCall to be executed by the caller, always null for this instruction

setNoSpecialChars

public void setNoSpecialChars()
Indicate that the attribute value contains no special characters that might need escaping

setRejectDuplicates

public void setRejectDuplicates()
Indicate that two attributes with the same name are not acceptable. (This option is set in XQuery, but not in XSLT)

setSelect

public void setSelect(Expression select,
                      Configuration config)
            throws XPathException
Set the expression defining the value of the attribute. If this is a constant, and if validation against a schema type was requested, the validation is done immediately.
Overrides:
setSelect in interface SimpleNodeConstructor
Parameters:
select - The expression defining the content of the attribute
config - The Saxon configuration
Throws:
XPathException - if the expression is a constant, and validation is requested, and the constant doesn't match the required type.