net.sf.saxon.instruct
Class Attribute

java.lang.Object
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  +--net.sf.saxon.instruct.Instruction
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        +--net.sf.saxon.instruct.ExprInstruction
              |
              +--net.sf.saxon.instruct.SimpleNodeConstructor
                    |
                    +--net.sf.saxon.instruct.Attribute

All Implemented Interfaces:

Expression, Instr, Locatable, java.io.Serializable, javax.xml.transform.SourceLocator

public final class Attribute

extends SimpleNodeConstructor

An instruction derived from an xsl:attribute element in stylesheet, or from an attribute constructor in XQuery

See Also:

Serialized Form

Field Summary

 

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

select, separator

 

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

children

 

Constructor Summary

Attribute(Expression attributeName, Expression namespace, NamespaceResolver nsContext, int validationAction, SimpleType schemaType, int annotation)           Construct an Attribute instruction

 

Method Summary
void	display(int level, NamePool pool)           Display this instruction as an expression, for diagnostics
protected  int	evaluateNameCode(XPathContext context)
int	getCardinality()           Determine the static cardinality of the expression.
int	getDependencies()           Determine which aspects of the context the expression depends on.
java.lang.String	getInstructionName()           Get the name of this instruction
ItemType	getItemType()           Determine the data type of the expression, if possible.
void	getXPathExpressions(java.util.List list)           Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)
TailCall	processLeavingTail(XPathContext context)           Process this instruction
void	promoteInst(PromotionOffer offer)           Offer promotion for subexpressions.
void	setRejectDuplicates()           Indicate that two attributes with the same name are not acceptable.
Expression	simplify()           Simplify an expression.
void	typeCheck(StaticContext env)

 

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

analyze, evaluateItem, expandChildren, setSelect, setSeparator

 

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

effectiveBooleanValue, evaluateAsString, getSpecialProperties, getSubExpressions, iterate, promote

 

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

assembleParams, assembleTunnelParams, displayChildren, dynamicError, dynamicError, getChildren, getColumnNumber, getExecutable, getInstructionNamespace, getLineNumber, getPublicId, getSourceLocator, getSystemId, process, processChildren, processChildrenLeavingTail, recoverableError, setChildren, setExecutable, setSourceLocation

 

Methods inherited from class java.lang.Object

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

 

Constructor Detail

Attribute

public Attribute(Expression attributeName,
                 Expression namespace,
                 NamespaceResolver nsContext,
                 int validationAction,
                 SimpleType schemaType,
                 int annotation)

Construct an Attribute instruction

Parameters:

attributeName - An expression to calculate the attribute name

namespace - An expression to calculate the attribute namespace

nsContext - a NamespaceContext object containing the static namespace context of the stylesheet instruction

annotation - Integer code identifying the type named in the type attribute of the instruction - zero if the attribute was not present

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)

getInstructionName

public java.lang.String getInstructionName()

Get the name of this instruction

Specified by:

getInstructionName in class Instruction

getItemType

public ItemType getItemType()

Description copied from interface: Expression

Determine the data type of the expression, if possible. All expression return sequences, in general; this method determines the type of the items within the sequence, assuming that (a) this is known in advance, and (b) it is the same for all items in the sequence.

This method should always return a result, though it may be the best approximation that is available at the time.

Specified by:

getItemType in interface Expression

Overrides:

getItemType in class Instruction

Returns:

a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)

getCardinality

public int getCardinality()

Description copied from interface: Expression

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.

This method should always return a result, though it may be the best approximation that is available at the time.

Specified by:

getCardinality in interface Expression

Overrides:

getCardinality in class Instruction

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).

simplify

public Expression simplify()
                    throws XPathException

Description copied from class: ExprInstruction

Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation does nothing.

Specified by:

simplify in interface Expression

Overrides:

simplify in class ExprInstruction

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

typeCheck

public void typeCheck(StaticContext env)
               throws XPathException

Specified by:

typeCheck in class SimpleNodeConstructor

XPathException

getDependencies

public int getDependencies()

Description copied from class: ExprInstruction

Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as StaticProperty.DEPENDS_ON_CONTEXT_ITEM and StaticProperty.DEPENDS_ON_CURRENT_ITEM. The default implementation combines the intrinsic dependencies of this expression with the dependencies of the subexpressions, computed recursively. This is overridden for expressions such as FilterExpression where a subexpression's dependencies are not necessarily inherited by the parent expression.

Specified by:

getDependencies in interface Expression

Overrides:

getDependencies in class ExprInstruction

Returns:

a set of bit-significant flags identifying the dependencies of the expression

getXPathExpressions

public void getXPathExpressions(java.util.List list)

Description copied from class: ExprInstruction

Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)

Overrides:

getXPathExpressions in class SimpleNodeConstructor

Parameters:

list - A list to be populated with the list of XPath expressions

promoteInst

public 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

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws javax.xml.transform.TransformerException

Process this instruction

Specified by:

processLeavingTail in interface Instr

Specified by:

processLeavingTail in class Instruction

Parameters:

context - the dynamic context of the transformation

Returns:

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

javax.xml.transform.TransformerException

evaluateNameCode

protected int evaluateNameCode(XPathContext context)
                        throws XPathException,
                               javax.xml.transform.TransformerException

Overrides:

evaluateNameCode in class SimpleNodeConstructor

XPathException

javax.xml.transform.TransformerException

display

public void display(int level,
                    NamePool pool)

Display this instruction as an expression, for diagnostics

Specified by:

display in interface Expression

Overrides:

display in class SimpleNodeConstructor

Parameters:

level - indentation level for this expression