Class Copy
- All Implemented Interfaces:
Serializable
,SourceLocator
,LocationProvider
,SaxonLocator
,EvaluableItem
,SequenceIterable
,TailCallReturner
,InstructionInfo
,Locator
- See Also:
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Field Summary
Fields inherited from class net.sf.saxon.instruct.ElementCreator
inheritNamespaces, preservingTypes
Fields inherited from class net.sf.saxon.instruct.ParentNodeConstructor
content
Fields inherited from class net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
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Constructor Summary
ConstructorsConstructorDescriptionCopy
(boolean copyNamespaces, boolean inheritNamespaces, SchemaType schemaType, int validation) Create a shallow copy instruction -
Method Summary
Modifier and TypeMethodDescriptioncopy()
Copy an expression.evaluateItem
(XPathContext context) Evaluate as an expression.void
Diagnostic print of expression structure.int[]
Callback to get a list of the intrinsic namespaces that need to be generated for the element.int
Get the name of this instruction for diagnostic and tracing purposesGet the item type of the result of this instruction.int
getNameCode
(XPathContext context) Callback from ElementCreator when constructing an elementgetNewBaseURI
(XPathContext context) Get the base URI of a copied element node (the base URI is retained in the new copy)optimize
(ExpressionVisitor visitor, ItemType contextItemType) Perform optimisation of an expression and its subexpressions.protected void
outputNamespaceNodes
(XPathContext context, Receiver receiver) Callback to output namespace nodes for the new element.processLeavingTail
(XPathContext context) Evaluate the instruction to produce a new element node.simplify
(ExpressionVisitor visitor) Simplify an expression.typeCheck
(ExpressionVisitor visitor, ItemType contextItemType) Perform type checking of an expression and its subexpressions.Methods inherited from class net.sf.saxon.instruct.ElementCreator
checkContentSequence, computeSpecialProperties, getImplementationMethod, isInheritNamespaces, isPreservingTypes, iterateEvents, setValidationMode, suppressValidation
Methods inherited from class net.sf.saxon.instruct.ParentNodeConstructor
addToPathMap, computeCardinality, createsNewNodes, getBaseURI, getCardinality, getContentExpression, getSchemaType, getValidationMode, isLazyConstruction, isNamespaceSensitive, iterateSubExpressions, promoteInst, replaceSubExpression, setBaseURI, setContentExpression, setLazyConstruction, setSchemaType
Methods inherited from class net.sf.saxon.instruct.Instruction
assembleParams, assembleTunnelParams, dynamicError, evaluateAsString, getConstructType, getSourceLocator, isXSLT, iterate, process, promote
Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, findParentOf, getColumnNumber, getColumnNumber, getContainer, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, 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
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Constructor Details
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Copy
public Copy(boolean copyNamespaces, boolean inheritNamespaces, SchemaType schemaType, int validation) Create a shallow copy instruction- Parameters:
copyNamespaces
- true if namespace nodes are to be copied when copying an elementinheritNamespaces
- true if child elements are to inherit the namespace nodes of their parentschemaType
- the Schema type against which the content is to be validatedvalidation
- the schema validation mode
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Method Details
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simplify
Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation does nothing.- Overrides:
simplify
in classParentNodeConstructor
- Parameters:
visitor
- an expression visitor- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException Description copied from class: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.
- Overrides:
typeCheck
in classParentNodeConstructor
- Parameters:
visitor
- an expression visitorcontextItemType
- 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
- if an error is discovered during this phase (typically a type error)
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copy
Copy an expression. This makes a deep copy.- Specified by:
copy
in classExpression
- Returns:
- the copy of the original expression
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getInstructionNameCode
public int getInstructionNameCode()Get the name of this instruction for diagnostic and tracing purposes- Overrides:
getInstructionNameCode
in classInstruction
- Returns:
- a code identifying the instruction: typically but not always the fingerprint of a name in the XSLT namespace
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getItemType
Get the item type of the result of this instruction.- Overrides:
getItemType
in classElementCreator
- Parameters:
th
- the type hierarchy cache- Returns:
- The context item type.
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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 classParentNodeConstructor
- Parameters:
visitor
- an expression visitorcontextItemType
- 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 if appropriate to optimize execution
- Throws:
XPathException
- if an error is discovered during this phase (typically a type error)
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getNameCode
Callback from ElementCreator when constructing an element- Specified by:
getNameCode
in classElementCreator
- Parameters:
context
- XPath dynamic evaluation context- Returns:
- the namecode of the element to be constructed
- Throws:
XPathException
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getNewBaseURI
Get the base URI of a copied element node (the base URI is retained in the new copy)- Specified by:
getNewBaseURI
in classElementCreator
- Parameters:
context
- XPath dynamic evaluation context- Returns:
- the base URI
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outputNamespaceNodes
Callback to output namespace nodes for the new element.- Specified by:
outputNamespaceNodes
in classElementCreator
- Parameters:
context
- The execution contextreceiver
- the Receiver where the namespace nodes are to be written- Throws:
XPathException
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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 classElementCreator
- 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.
- Throws:
XPathException
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processLeavingTail
Description copied from class:ElementCreator
Evaluate the instruction to produce a new element node. This method is typically used when there is a parent element or document in a result tree, to which the new element is added.- Specified by:
processLeavingTail
in interfaceTailCallReturner
- Overrides:
processLeavingTail
in classElementCreator
- Parameters:
context
- XPath dynamic evaluation context- Returns:
- null (this instruction never returns a tail call)
- Throws:
XPathException
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evaluateItem
Evaluate as an expression. We rely on the fact that when these instructions are generated by XQuery, there will always be a valueExpression to evaluate the content- Specified by:
evaluateItem
in interfaceEvaluableItem
- Overrides:
evaluateItem
in classElementCreator
- Parameters:
context
- The context in which the expression is to be evaluated- Returns:
- the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
- Throws:
XPathException
- if any dynamic error occurs evaluating the expression
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explain
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Specified by:
explain
in classExpression
- Parameters:
out
- the expression presenter used to display the structure
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