net.sf.saxon.instruct
Class Element

java.lang.Object
  net.sf.saxon.instruct.Instruction
      net.sf.saxon.instruct.ExprInstruction
          net.sf.saxon.instruct.ElementCreator
              net.sf.saxon.instruct.Element

All Implemented Interfaces:

Serializable, SourceLocator, Expression

public class Element
extends ElementCreator

An instruction representing xsl:element element in the stylesheet.

See Also:

Serialized Form

Field Summary

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

schemaType, useAttributeSets, validation, validationContext

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

children

Constructor Summary

Element(Expression elementName, Expression namespace, NamespaceResolver nsContext, AttributeSet[] useAttributeSets, SchemaType schemaType, int validation)
Create an instruction that creates a new element node

Method Summary

Expression	analyze(StaticContext env) Perform static analysis of an expression and its subexpressions.
void	display(int level, NamePool pool) Display this instruction as an expression, for diagnostics
protected int	getNameCode(XPathContext context) Callback from the superclass ElementCreator to get the nameCode for the element name
void	getXPathExpressions(List list)
protected void	outputNamespaceNodes(XPathContext context, Receiver out) Callback to output namespace nodes for the new element.
void	promoteInst(PromotionOffer offer) Offer promotion for subexpressions.
void	setInstructionDetails(Controller controller, NamePool namePool, InstructionDetails details) Get the name of this instruction for diagnostic and tracing purposes
Expression	simplify() Simplify an expression.

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

evaluateItem, getResultType, getValidationContext, getValidationMode, processLeavingTail, setValidationContext, setValidationMode

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

effectiveBooleanValue, evaluateAsString, getCardinality, getDependencies, getItemType, getSpecialProperties, getSubExpressions, iterate, promote

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

assembleParams, assembleTunnelParams, getChildren, getColumnNumber, getInstructionDetails, getInstructionName, getLineNumber, getPublicId, getSystemId, getSystemId, process, processChildren, processChildrenLeavingTail, recoverableError, setChildren, setSourceLocation, styleError, styleError

Methods inherited from class java.lang.Object

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

Constructor Detail

Element

public Element(Expression elementName,
               Expression namespace,
               NamespaceResolver nsContext,
               AttributeSet[] useAttributeSets,
               SchemaType schemaType,
               int validation)
        throws XPathException

Create an instruction that creates a new element node

Parameters:

elementName - Expression that evaluates to produce the name of the element node as a lexical QName

namespace - Expression that evaluates to produce the namespace URI of the element node. Set to null if the namespace is to be deduced from the prefix of the elementName.

nsContext - Saved copy of the static namespace context for the instruction. Can be set to null if namespace is supplied.

useAttributeSets - Array of attribute sets to be expanded

schemaType - The required schema type for the content

Throws:

XPathException

Method Detail

simplify

public Expression simplify()
                    throws XPathException

Description copied from interface: Expression

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

analyze

public Expression analyze(StaticContext env)
                   throws XPathException

Description copied from interface: Expression

Perform static analysis of an expression and its subexpressions.

This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables will only be accurately known if they have been explicitly declared.

Specified by:

analyze in interface Expression

Overrides:

analyze in class ElementCreator

Parameters:

env - the static context of the expression

Returns:

the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

Throws:

XPathException - if an error is discovered during this phase (typically a type error)

getXPathExpressions

public void getXPathExpressions(List list)

Specified by:

getXPathExpressions in class ExprInstruction

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 ElementCreator

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

getNameCode

protected int getNameCode(XPathContext context)
                   throws XPathException,
                          TransformerException

Callback from the superclass ElementCreator to get the nameCode for the element name

Specified by:

getNameCode in class ElementCreator

Parameters:

context - The evaluation context (not used)

Returns:

the name code for the element name

Throws:

XPathException

TransformerException

outputNamespaceNodes

protected void outputNamespaceNodes(XPathContext context,
                                    Receiver out)
                             throws TransformerException

Callback to output namespace nodes for the new element.

Specified by:

outputNamespaceNodes in class ElementCreator

Parameters:

context - The execution context

out - the Receiver where the namespace nodes are to be written

Throws:

TransformerException

setInstructionDetails

public void setInstructionDetails(Controller controller,
                                  NamePool namePool,
                                  InstructionDetails details)

Get the name of this instruction for diagnostic and tracing purposes

Specified by:

setInstructionDetails in class Instruction

display

public void display(int level,
                    NamePool pool)

Display this instruction as an expression, for diagnostics

Parameters:

level - indentation level for this expression