net.sf.saxon.instruct
Class Element

java.lang.Object
  extended bynet.sf.saxon.expr.ComputedExpression
      extended bynet.sf.saxon.instruct.Instruction
          extended bynet.sf.saxon.instruct.ElementCreator
              extended bynet.sf.saxon.instruct.Element
All Implemented Interfaces:
Container, Expression, InstructionInfoProvider, java.io.Serializable, javax.xml.transform.SourceLocator

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
content, inheritNamespaces, schemaType, useAttributeSets, validation
 
Fields inherited from class net.sf.saxon.expr.ComputedExpression
locationId, staticProperties
 
Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
 
Constructor Summary
Element(Expression elementName, Expression namespace, NamespaceResolver nsContext, AttributeSet[] useAttributeSets, SchemaType schemaType, int validation, boolean inheritNamespaces)
          Create an instruction that creates a new element node
 
Method Summary
 Expression analyze(StaticContext env, ItemType contextItemType)
          Perform static analysis of an expression and its subexpressions.
 void checkPermittedContents(SchemaType parentType, StaticContext env, boolean whole)
          Check that any elements and attributes constructed or returned by this expression are acceptable in the content model of a given complex type.
 void display(int level, NamePool pool, java.io.PrintStream out)
          Display this instruction as an expression, for diagnostics
 int getInstructionNameCode()
          Get the name of this instruction for diagnostic and tracing purposes
 ItemType getItemType()
          Get the item type of the value returned by this instruction
protected  int getNameCode(XPathContext context)
          Callback from the superclass ElementCreator to get the nameCode for the element name
 java.util.Iterator iterateSubExpressions()
          Get the immediate sub-expressions of this expression.
protected  void outputNamespaceNodes(XPathContext context, Receiver out)
          Callback to output namespace nodes for the new element.
protected  void promoteInst(PromotionOffer offer)
          Offer promotion for subexpressions.
 Expression simplify(StaticContext env)
          Simplify an expression.
 
Methods inherited from class net.sf.saxon.instruct.ElementCreator
computeSpecialProperties, createsNewNodes, evaluateItem, getCardinality, getImplementationMethod, getValidationMode, processLeavingTail, setContent, setValidationMode
 
Methods inherited from class net.sf.saxon.instruct.Instruction
appendItem, assembleParams, assembleTunnelParams, computeCardinality, dynamicError, dynamicError, effectiveBooleanValue, evaluateAsString, getInstructionInfo, getSourceLocator, isXSLT, iterate, process, promote
 
Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, computeDependencies, computeStaticProperties, dynamicError, dynamicError, getColumnNumber, getConstructType, getDependencies, getExecutable, getIntrinsicDependencies, getLineNumber, getLocationId, getParentExpression, getPublicId, getSpecialProperties, getSystemId, markTailFunctionCalls, resetStaticProperties, setLocationId, setParentExpression, typeError, typeError
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface javax.xml.transform.SourceLocator
getColumnNumber, getLineNumber, getPublicId, getSystemId
 

Constructor Detail

Element

public Element(Expression elementName,
               Expression namespace,
               NamespaceResolver nsContext,
               AttributeSet[] useAttributeSets,
               SchemaType schemaType,
               int validation,
               boolean inheritNamespaces)
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
Method Detail

simplify

public Expression simplify(StaticContext env)
                    throws XPathException
Description copied from class: ElementCreator
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 ElementCreator
Returns:
the simplified expression
Throws:
XPathException - if an error is discovered during expression rewriting

analyze

public Expression analyze(StaticContext env,
                          ItemType contextItemType)
                   throws XPathException
Description copied from class: ElementCreator
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)

getItemType

public ItemType getItemType()
Get the item type of the value returned by this instruction

Specified by:
getItemType in interface Expression
Overrides:
getItemType in class ElementCreator
Returns:
the item type

iterateSubExpressions

public java.util.Iterator iterateSubExpressions()
Description copied from class: ElementCreator
Get the immediate sub-expressions of this expression.

Specified by:
iterateSubExpressions in interface Expression
Overrides:
iterateSubExpressions in class ElementCreator
Returns:
an iterator containing the sub-expressions of this expression

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 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

checkPermittedContents

public void checkPermittedContents(SchemaType parentType,
                                   StaticContext env,
                                   boolean whole)
                            throws XPathException
Check that any elements and attributes constructed or returned by this expression are acceptable in the content model of a given complex type. It's always OK to say yes, since the check will be repeated at run-time. The process of checking element and attribute constructors against the content model of a complex type also registers the type of content expected of those constructors, so the static validation can continue recursively.

Specified by:
checkPermittedContents in interface Expression
Overrides:
checkPermittedContents in class ComputedExpression
Throws:
XPathException

getNameCode

protected int getNameCode(XPathContext context)
                   throws XPathException,
                          XPathException
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

outputNamespaceNodes

protected void outputNamespaceNodes(XPathContext context,
                                    Receiver out)
                             throws XPathException
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:
XPathException

getInstructionNameCode

public int getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposes

Overrides:
getInstructionNameCode in class Instruction

display

public void display(int level,
                    NamePool pool,
                    java.io.PrintStream out)
Display this instruction as an expression, for diagnostics

Parameters:
level - indentation level for this expression
pool - NamePool used to expand any names appearing in the expression
out - Output destination