## 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:
  java.io.Serializable, javax.xml.transform.SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, TailCallReturner, InstructionInfo, org.xml.sax.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 java.lang.String` `checkContent(java.lang.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
`java.util.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.
`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, 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, display, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, findParentOf, getColumnNumber, getColumnNumber, getContainer, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterateEvents, 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 java.util.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

### 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

### 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

### checkContent

    protected java.lang.String checkContent(java.lang.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.