Class ComputedElement
- All Implemented Interfaces:
Serializable
,SourceLocator
,Container
,Expression
,TailCallReturner
,InstructionInfoProvider
- See Also:
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Field Summary
Fields inherited from class net.sf.saxon.instruct.ElementCreator
inheritNamespaces, validating
Fields inherited from class net.sf.saxon.instruct.ParentNodeConstructor
content, 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
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Constructor Summary
ConstructorsConstructorDescriptionComputedElement
(Expression elementName, Expression namespace, NamespaceResolver nsContext, SchemaType schemaType, int validation, boolean inheritNamespaces, boolean allowQName) Create an instruction that creates a new element node -
Method Summary
Modifier and TypeMethodDescriptionvoid
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, PrintStream out, Configuration config) Display this instruction as an expression, for diagnosticsint
Get the name of this instruction for diagnostic and tracing purposesGet the item type of the value returned by this instructionint
getNameCode
(XPathContext context) Callback from the superclass ElementCreator to get the nameCode for the element namegetNewBaseURI
(XPathContext context) Get the base URI for the element being constructedGet 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.boolean
replaceSubExpression
(Expression original, Expression replacement) Replace one subexpression by a replacement subexpressionsimplify
(StaticContext env) Simplify an expression.typeCheck
(StaticContext env, ItemType contextItemType) Perform type checking of an expression and its subexpressions.Methods inherited from class net.sf.saxon.instruct.ElementCreator
checkContentForAttributes, computeSpecialProperties, evaluateItem, getActiveNamespaces, getImplementationMethod, getValidationMode, isInheritNamespaces, isValidating, processLeavingTail, setValidationMode, suppressValidation
Methods inherited from class net.sf.saxon.instruct.ParentNodeConstructor
createsNewNodes, getBaseURI, getCardinality, getContentExpression, getSchemaType, getValidationAction, isLazyConstruction, isNamespaceSensitive, optimize, setBaseURI, setContentExpression, setLazyConstruction, setSchemaType, verifyLazyConstruction
Methods inherited from class net.sf.saxon.instruct.Instruction
appendItem, assembleParams, assembleTunnelParams, computeCardinality, dynamicError, evaluateAsString, getInstructionInfo, getSourceLocator, isXSLT, iterate, process, promote
Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, 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
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Constructor Details
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ComputedElement
public ComputedElement(Expression elementName, Expression namespace, NamespaceResolver nsContext, SchemaType schemaType, int validation, boolean inheritNamespaces, boolean allowQName) 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 QNamenamespace
- 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.schemaType
- The required schema type for the contentallowQName
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Method Details
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simplify
Description copied from class:ParentNodeConstructor
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 interfaceExpression
- Overrides:
simplify
in classParentNodeConstructor
- Parameters:
env
- the static context- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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typeCheck
Description copied from interface:Expression
Perform type checking of an expression and its subexpressions. This is the second phase of static optimization.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 may not be accurately known if they have not been explicitly declared.
If the implementation returns a value other than "this", then it is required to ensure that the parent pointer and location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.
- Specified by:
typeCheck
in interfaceExpression
- Overrides:
typeCheck
in classParentNodeConstructor
- Parameters:
env
- the static context of the expressioncontextItemType
- 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 toType.ITEM_TYPE
- Returns:
- the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
- Throws:
XPathException
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getItemType
Get the item type of the value returned by this instruction- Specified by:
getItemType
in interfaceExpression
- Overrides:
getItemType
in classElementCreator
- Parameters:
th
-- Returns:
- the item type
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iterateSubExpressions
Description copied from class:ParentNodeConstructor
Get the immediate sub-expressions of this expression.- Specified by:
iterateSubExpressions
in interfaceExpression
- Overrides:
iterateSubExpressions
in classParentNodeConstructor
- Returns:
- an iterator containing the sub-expressions of this expression
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replaceSubExpression
Replace one subexpression by a replacement subexpression- Specified by:
replaceSubExpression
in interfaceContainer
- Overrides:
replaceSubExpression
in classParentNodeConstructor
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression- Returns:
- true if the original subexpression is found
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promoteInst
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 classParentNodeConstructor
- 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
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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 interfaceExpression
- Overrides:
checkPermittedContents
in classComputedExpression
- Parameters:
parentType
- The schema typeenv
- the static contextwhole
- true if this expression is expected to make the whole content of the type, false if it is expected to make up only a part- Throws:
XPathException
- if the expression doesn't match the required content type
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getNameCode
Callback from the superclass ElementCreator to get the nameCode for the element name- Specified by:
getNameCode
in classElementCreator
- Parameters:
context
- The evaluation context (not used)- Returns:
- the name code for the element name
- Throws:
XPathException
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getNewBaseURI
Description copied from class:ElementCreator
Get the base URI for the element being constructed- Specified by:
getNewBaseURI
in classElementCreator
- Parameters:
context
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outputNamespaceNodes
Callback to output namespace nodes for the new element.- Specified by:
outputNamespaceNodes
in classElementCreator
- Parameters:
context
- The execution contextout
- the Receiver where the namespace nodes are to be written- Throws:
XPathException
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getInstructionNameCode
public int getInstructionNameCode()Get the name of this instruction for diagnostic and tracing purposes- Overrides:
getInstructionNameCode
in classInstruction
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display
Display this instruction as an expression, for diagnostics- Parameters:
level
- indentation level for this expressionout
- Output destinationconfig
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