net.sf.saxon.instruct
Class ProcessingInstruction

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.instruct.Instruction
          net.sf.saxon.instruct.SimpleNodeConstructor
              net.sf.saxon.instruct.ProcessingInstruction

All Implemented Interfaces:

Serializable, SourceLocator, EvaluableItem, SequenceIterable, TailCallReturner, InstructionInfoProvider

public class ProcessingInstruction
extends SimpleNodeConstructor

An xsl:processing-instruction element in the stylesheet, or a processing-instruction constructor in a query

See Also:

Serialized Form

Field Summary

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

ProcessingInstruction(Expression name)
Create an xsl:processing-instruction instruction

Method Summary

Expression	copy() Copy 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	getCardinality() Determine the static cardinality of the expression.
int	getDependencies() Determine which aspects of the context the expression depends on.
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
Expression	getNameExpression() Get the expression that defines the processing instruction name
Iterator	iterateSubExpressions() Get the immediate sub-expressions of this expression.
void	localTypeCheck(ExpressionVisitor visitor, ItemType contextItemType) Method to perform type-checking specific to the kind of instruction
TailCall	processLeavingTail(XPathContext context) Process this instruction, that is, produce a processing-instruction node in the result sequence.
boolean	replaceSubExpression(Expression original, Expression replacement) Replace one subexpression by a replacement subexpression
Expression	simplify(ExpressionVisitor visitor) Simplify an expression.

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

computeCardinality, computeSpecialProperties, createsNewNodes, evaluateItem, expandChildren, getSelect, iterate, optimize, setSelect, typeCheck

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

evaluateAsString, getImplementationMethod, getInstructionInfo, getSourceLocator, isXSLT, process, promote

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

addToPathMap, adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, effectiveBooleanValue, explain, findParentOf, getColumnNumber, getContainer, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterateEvents, markTailFunctionCalls, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface javax.xml.transform.SourceLocator

getColumnNumber, getLineNumber, getPublicId, getSystemId

Constructor Detail

ProcessingInstruction

public ProcessingInstruction(Expression name)

Create an xsl:processing-instruction instruction

Parameters:

name - the expression used to compute the name of the generated processing-instruction

Method Detail

getInstructionNameCode

public int getInstructionNameCode()

Get the name of this instruction for diagnostic and tracing purposes

Overrides:

getInstructionNameCode in class Instruction

Returns:

the string "xsl:processing-instruction"

getNameExpression

public Expression getNameExpression()

Get the expression that defines the processing instruction name

Returns:

the expression that defines the processing instruction name

getItemType

public ItemType getItemType(TypeHierarchy th)

Description copied from class: Instruction

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

Overrides:

getItemType in class Instruction

Parameters:

th - the type hierarchy cache

Returns:

the static item type of the instruction

getCardinality

public int getCardinality()

Description copied from class: 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.

Overrides:

getCardinality in class 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).

simplify

public Expression simplify(ExpressionVisitor visitor)
                    throws XPathException

Description copied from class: Instruction

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

Overrides:

simplify in class SimpleNodeConstructor

Parameters:

visitor - an expression visitor

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

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

localTypeCheck

public void localTypeCheck(ExpressionVisitor visitor,
                           ItemType contextItemType)
                    throws XPathException

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

Throws:

XPathException

getDependencies

public int getDependencies()

Description copied from class: Expression

Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as XPathContext.VARIABLES and XPathContext.CURRENT_NODE. 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.

Overrides:

getDependencies in class Expression

Returns:

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

iterateSubExpressions

public Iterator iterateSubExpressions()

Description copied from class: Expression

Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.

Overrides:

iterateSubExpressions in class SimpleNodeConstructor

Returns:

an iterator containing the sub-expressions of this expression

replaceSubExpression

public boolean replaceSubExpression(Expression original,
                                    Expression replacement)

Replace one subexpression by a replacement subexpression

Overrides:

replaceSubExpression in class SimpleNodeConstructor

Parameters:

original - the original subexpression

replacement - the replacement subexpression

Returns:

true if the original subexpression is found

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws XPathException

Process this instruction, that is, produce a processing-instruction node in the result sequence.

Specified by:

processLeavingTail in interface TailCallReturner

Specified by:

processLeavingTail in class Instruction

Parameters:

context - the dynamic context of this transformation

Returns:

always returns null in this implementation

Throws:

XPathException - if any non-recoverable dynamic error occurs

evaluateNameCode

public int evaluateNameCode(XPathContext context)
                     throws XPathException

Description copied from class: SimpleNodeConstructor

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 class SimpleNodeConstructor

Parameters:

context - the XPath dynamic evaluation context

Returns:

the name pool nameCode identifying the name of the constructed node

Throws:

XPathException - if any failure occurs

explain

public void explain(ExpressionPresenter out)

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

Specified by:

explain in class Expression

Parameters:

out - the expression presenter used to display the structure