net.sf.saxon.instruct
Class ProcessingInstruction

java.lang.Object
  extended by net.sf.saxon.expr.Expression
      extended by net.sf.saxon.instruct.Instruction
          extended by net.sf.saxon.instruct.SimpleNodeConstructor
              extended by net.sf.saxon.instruct.ProcessingInstruction
All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, DivisibleInstruction, TailCallReturner, InstructionInfo, Locator

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.instruct.SimpleNodeConstructor
select
 
Fields inherited from class net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
 
Constructor Summary
ProcessingInstruction(Expression name)
          Create an xsl:processing-instruction instruction
 
Method Summary
protected  String checkContent(String data, XPathContext context)
          Check the content of the node, and adjust it if necessary
 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<Expression> 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
 void processValue(CharSequence value, XPathContext context)
          Process the value of the node, to create the new node.
protected  void promoteInst(PromotionOffer offer)
          Offer promotion for subexpressions.
 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, processLeavingTail, processLeft, processRight, setSelect, typeCheck
 
Methods inherited from class net.sf.saxon.instruct.Instruction
assembleParams, assembleTunnelParams, dynamicError, evaluateAsString, getConstructType, getImplementationMethod, getSourceLocator, isXSLT, process, promote
 
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getColumnNumber, getColumnNumber, getContainer, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toString, typeError
 
Methods inherited from class java.lang.Object
clone, equals, finalize, 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<Expression> 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

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

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

checkContent

protected String checkContent(String data,
                              XPathContext context)
                       throws XPathException
Check the content of the node, and adjust it if necessary

Overrides:
checkContent in class SimpleNodeConstructor
Parameters:
data - the supplied content
context - the dynamic context
Returns:
the original content, unless adjustments are needed
Throws:
XPathException - if the content is invalid

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


Copyright (c) Saxonica Limited. All rights reserved.