Class Copy
- java.lang.Object
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,LocationProvider
,SaxonLocator
,EvaluableItem
,SequenceIterable
,TailCallReturner
,InstructionInfo
,org.xml.sax.Locator
public class Copy extends ElementCreator
Handler for xsl:copy elements in stylesheet.- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class net.sf.saxon.instruct.ElementCreator
inheritNamespaces, preservingTypes
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Fields inherited from class net.sf.saxon.instruct.ParentNodeConstructor
content
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Fields inherited from class net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
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Constructor Summary
Constructors Constructor Description Copy(boolean copyNamespaces, boolean inheritNamespaces, SchemaType schemaType, int validation)
Create a shallow copy instruction
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Expression
copy()
Copy an expression.Item
evaluateItem(XPathContext context)
Evaluate as 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.int
getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposesItemType
getItemType(TypeHierarchy th)
Get the item type of the result of this instruction.int
getNameCode(XPathContext context)
Callback from ElementCreator when constructing an elementjava.lang.String
getNewBaseURI(XPathContext context)
Get the base URI of a copied element node (the base URI is retained in the new copy)Expression
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.TailCall
processLeavingTail(XPathContext context)
Evaluate the instruction to produce a new element node.Expression
simplify(ExpressionVisitor visitor)
Simplify an expression.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
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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
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Methods inherited from class net.sf.saxon.instruct.Instruction
assembleParams, assembleTunnelParams, dynamicError, evaluateAsString, getConstructType, getSourceLocator, isXSLT, iterate, process, promote
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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
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Constructor Detail
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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 Detail
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simplify
public Expression simplify(ExpressionVisitor visitor) throws XPathException
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
public Expression 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
public ItemType getItemType(TypeHierarchy th)
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
public int getNameCode(XPathContext context) throws XPathException
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
public java.lang.String getNewBaseURI(XPathContext context)
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
protected void outputNamespaceNodes(XPathContext context, Receiver receiver) throws XPathException
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
public int[] getActiveNamespaces() throws XPathException
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
public TailCall processLeavingTail(XPathContext context) throws XPathException
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
public Item evaluateItem(XPathContext context) throws XPathException
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
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 classExpression
- Parameters:
out
- the expression presenter used to display the structure
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