net.sf.saxon.instruct
Class FixedElement

java.lang.Object
  extended by net.sf.saxon.expr.Expression
      extended by net.sf.saxon.instruct.Instruction
          extended by net.sf.saxon.instruct.ParentNodeConstructor
              extended by net.sf.saxon.instruct.ElementCreator
                  extended by net.sf.saxon.instruct.FixedElement
All Implemented Interfaces:
Serializable, SourceLocator, EvaluableItem, SequenceIterable, TailCallReturner, InstructionInfoProvider

public class FixedElement
extends ElementCreator

An instruction that creates an element node whose name is known statically. Used for literal results elements in XSLT, for direct element constructors in XQuery, and for xsl:element in cases where the name and namespace are known statically.

See Also:
Serialized Form

Field Summary
 
Fields inherited from class net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
 
Constructor Summary
FixedElement(int nameCode, int[] namespaceCodes, boolean inheritNamespaces, SchemaType schemaType, int validation)
          Create an instruction that creates a new element node
 
Method Summary
 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.
 Expression copy()
          Copy an expression.
 void explain(ExpressionPresenter out)
          Diagnostic print of expression structure.
 int[] getActiveNamespaces()
          Callback to get a list of the intrinsic namespaces that need to be generated for the element.
 InstructionInfo getInstructionInfo()
          Get InstructionInfo for this expression
 ItemType getItemType(TypeHierarchy th)
          Get the type of the item returned by this instruction
 int getNameCode(XPathContext context)
          Callback from the superclass ElementCreator to get the nameCode for the element name
 String getNewBaseURI(XPathContext context)
          Get the base URI for the element being constructed
 short getURICode(NamePool pool)
          Get the URI code representing the namespace URI of the element being constructed
 Expression optimize(ExpressionVisitor visitor, ItemType contextItemType)
          Perform optimisation of an expression and its subexpressions.
 Expression simplify(ExpressionVisitor visitor)
          Simplify an expression.
 
Methods inherited from class net.sf.saxon.instruct.ElementCreator
computeSpecialProperties, evaluateItem, getImplementationMethod, isInheritNamespaces, isPreservingTypes, iterateEvents, processLeavingTail, setValidationMode, suppressValidation
 
Methods inherited from class net.sf.saxon.instruct.ParentNodeConstructor
addToPathMap, computeCardinality, createsNewNodes, getBaseURI, getCardinality, getContentExpression, getSchemaType, getValidationMode, isLazyConstruction, isNamespaceSensitive, iterateSubExpressions, replaceSubExpression, setBaseURI, setContentExpression, setLazyConstruction, setSchemaType, typeCheck
 
Methods inherited from class net.sf.saxon.instruct.Instruction
evaluateAsString, getInstructionNameCode, getSourceLocator, isXSLT, iterate, process, promote
 
Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, computeDependencies, computeStaticProperties, display, doPromotion, effectiveBooleanValue, explain, findParentOf, getColumnNumber, getContainer, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, markTailFunctionCalls, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, 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

FixedElement

public FixedElement(int nameCode,
                    int[] namespaceCodes,
                    boolean inheritNamespaces,
                    SchemaType schemaType,
                    int validation)
Create an instruction that creates a new element node

Parameters:
nameCode - Represents the name of the element node
namespaceCodes - List of namespaces to be added to the element node. May be null if none are required.
inheritNamespaces - true if the children of this element are to inherit its namespaces
schemaType - Type annotation for the new element node
validation - Validation mode to be applied, for example STRICT, LAX, SKIP
Method Detail

getInstructionInfo

public InstructionInfo getInstructionInfo()
Description copied from class: Expression
Get InstructionInfo for this expression

Specified by:
getInstructionInfo in interface InstructionInfoProvider
Overrides:
getInstructionInfo in class Instruction

simplify

public Expression simplify(ExpressionVisitor visitor)
                    throws XPathException
Simplify an expression. This performs any context-independent rewriting

Overrides:
simplify in class ParentNodeConstructor
Parameters:
visitor - the expression visitor
Returns:
the simplified expression
Throws:
XPathException - if an error is discovered during expression rewriting

optimize

public Expression optimize(ExpressionVisitor visitor,
                           ItemType contextItemType)
                    throws XPathException
Description copied from class: Expression
Perform optimisation of an expression and its subexpressions. This is the third and final phase of static optimization.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

Overrides:
optimize in class ParentNodeConstructor
Parameters:
visitor - an expression visitor
contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
Returns:
the original expression, rewritten if appropriate to optimize execution
Throws:
XPathException - if an error is discovered during this phase (typically a type error)

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

getURICode

public short getURICode(NamePool pool)
Get the URI code representing the namespace URI of the element being constructed

Parameters:
pool - the NamePool
Returns:
the URI code

getItemType

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

Overrides:
getItemType in class ElementCreator
Parameters:
th - The type hierarchy cache
Returns:
the item type

getNameCode

public int getNameCode(XPathContext context)
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

getNewBaseURI

public String getNewBaseURI(XPathContext context)
Description copied from class: ElementCreator
Get the base URI for the element being constructed

Specified by:
getNewBaseURI in class ElementCreator
Parameters:
context - the XPath dynamic evaluation context
Returns:
the base URI of the constructed element

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.

Overrides:
checkPermittedContents in class Expression
Parameters:
parentType - the "given complex type": the method is checking that the nodes returned by this expression are acceptable members of the content model of this type
env - the static context
whole - if true, we want to check that the value of this expression satisfies the content model as a whole; if false we want to check that the value of the expression is acceptable as one part of the content
Throws:
XPathException - if the value delivered by this expression cannot be part of the content model of the given type

getActiveNamespaces

public int[] getActiveNamespaces()
Callback to get a list of the intrinsic namespaces that need to be generated for the element. The result is an array of namespace codes, the codes either occupy the whole array or are terminated by a -1 entry. A result of null is equivalent to a zero-length array.

Overrides:
getActiveNamespaces in class ElementCreator
Returns:
an array of namespace codes, the codes either occupy the whole array or are terminated by a -1 entry. A result of null is equivalent to a zero-length array.

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) Michael H. Kay. All rights reserved.