Class Copy
- java.lang.Object
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,LocationProvider
,SaxonLocator
,DivisibleInstruction
,TailCallReturner
,ValidatingInstruction
,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.expr.instruct.ElementCreator
inheritNamespaces
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Fields inherited from class net.sf.saxon.expr.instruct.ParentNodeConstructor
content, preservingTypes, validation
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Fields inherited from class net.sf.saxon.expr.Expression
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD
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Constructor Summary
Constructors Constructor Description Copy(Expression select, boolean selectSpecified, 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.NamespaceBinding[]
getActiveNamespaces()
Callback to get a list of the intrinsic namespaces that need to be generated for the element.NodeName
getElementName(XPathContext context, NodeInfo copiedNode)
Callback from ElementCreator when constructing an elementint
getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposesint
getIntrinsicDependencies()
Determine which aspects of the context the expression depends on.ItemType
getItemType(TypeHierarchy th)
Get the item type of the result of this instruction.java.lang.String
getNewBaseURI(XPathContext context, NodeInfo copiedNode)
Get the base URI of a copied element node (the base URI is retained in the new copy)Expression
getSelectExpression()
Get the expression that selects the node or other item to be copiedboolean
isCopyNamespaces()
Ask whether namespace nodes are to be copied (in the case of an element)boolean
isSelectSpecified()
Ask whether the select attribute was explicitly specifiedjava.util.Iterator<Expression>
iterateSubExpressions()
Get the immediate sub-expressions of this expression.Expression
optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions.protected void
outputNamespaceNodes(XPathContext context, Receiver receiver, NodeName nameCode, NodeInfo copiedNode)
Callback to output namespace nodes for the new element.TailCall
processLeavingTail(XPathContext context)
Evaluate the instruction to produce a new element node.void
processLeft(java.util.Stack<XPathContext> contextStack, java.util.Stack<java.lang.Object> state)
Process the first half of the instruction in streaming modevoid
processRight(java.util.Stack<XPathContext> contextStack, java.util.Stack<java.lang.Object> state)
Process the second half of the instruction in streaming modeprotected void
promoteInst(PromotionOffer offer)
Handle promotion offers, that is, non-local tree rewrites.boolean
replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpressionExpression
simplify(ExpressionVisitor visitor)
Simplify an expression.Expression
typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)
Perform type checking of an expression and its subexpressions.-
Methods inherited from class net.sf.saxon.expr.instruct.ElementCreator
checkContentSequence, computeSpecialProperties, getImplementationMethod, isInheritNamespaces, iterateEvents, iterateEvents, processLeavingTail, processLeft, suppressValidation
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Methods inherited from class net.sf.saxon.expr.instruct.ParentNodeConstructor
addToPathMap, computeCardinality, createsNewNodes, getBaseURI, getCardinality, getContentExpression, getSchemaType, getValidationAction, isLazyConstruction, isNamespaceSensitive, isPreservingTypes, setBaseURI, setContentExpression, setLazyConstruction, setNoNeedToStrip, setSchemaType, setValidationAction, verifyLazyConstruction
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Methods inherited from class net.sf.saxon.expr.instruct.Instruction
assembleParams, assembleTunnelParams, dynamicError, evaluateAsString, getConstructType, getExpressionName, getInstructionName, getIteratorFromProcessMethod, getSourceLocator, isXSLT, iterate, process, promote
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Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getColumnNumber, getColumnNumber, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getIntegerBounds, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateSameFocusSubExpressions, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, toString, typeError
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Constructor Detail
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Copy
public Copy(Expression select, boolean selectSpecified, boolean copyNamespaces, boolean inheritNamespaces, SchemaType schemaType, int validation)
Create a shallow copy instruction- Parameters:
select
- selects the node (or other item) to be copied. Never null.selectSpecified
- true if the select attribute of xsl:copy was specified explicitly (in which case the context for evaluating the body will change)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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getSelectExpression
public Expression getSelectExpression()
Get the expression that selects the node or other item to be copied- Returns:
- the select expression. This will be a context item expression if no select attribute was supplied.
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isSelectSpecified
public boolean isSelectSpecified()
Ask whether the select attribute was explicitly specified- Returns:
- true if it was
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isCopyNamespaces
public boolean isCopyNamespaces()
Ask whether namespace nodes are to be copied (in the case of an element)- Returns:
- true if all in-scope namespaces are to be copied
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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, ExpressionVisitor.ContextItemType 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 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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replaceSubExpression
public boolean replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpression- Overrides:
replaceSubExpression
in classParentNodeConstructor
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression- Returns:
- true if the original subexpression is found
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getIntrinsicDependencies
public int getIntrinsicDependencies()
Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as XPathContext.VARIABLES and XPathContext.CURRENT_NODE. The default implementation combines the intrinsic dependencies of this expression with the dependencies of the subexpressions, computed recursively. This is overridden for expressions such as FilterExpression where a subexpression's dependencies are not necessarily inherited by the parent expression.- Overrides:
getIntrinsicDependencies
in classExpression
- Returns:
- a set of bit-significant flags identifying the dependencies of the 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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iterateSubExpressions
public java.util.Iterator<Expression> iterateSubExpressions()
Get the immediate sub-expressions of this expression.- Overrides:
iterateSubExpressions
in classParentNodeConstructor
- Returns:
- an iterator containing the sub-expressions of this expression
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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, ExpressionVisitor.ContextItemType 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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promoteInst
protected void promoteInst(PromotionOffer offer) throws XPathException
Description copied from class:ParentNodeConstructor
Handle promotion offers, that is, non-local tree rewrites.- Overrides:
promoteInst
in classParentNodeConstructor
- Parameters:
offer
- The type of rewrite being offered- Throws:
XPathException
- if an error occurs
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getElementName
public NodeName getElementName(XPathContext context, NodeInfo copiedNode) throws XPathException
Callback from ElementCreator when constructing an element- Specified by:
getElementName
in classElementCreator
- Parameters:
context
- XPath dynamic evaluation contextcopiedNode
- the node being copied- Returns:
- the namecode of the element to be constructed
- Throws:
XPathException
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getNewBaseURI
public java.lang.String getNewBaseURI(XPathContext context, NodeInfo copiedNode)
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 contextcopiedNode
-- Returns:
- the base URI
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outputNamespaceNodes
protected void outputNamespaceNodes(XPathContext context, Receiver receiver, NodeName nameCode, NodeInfo copiedNode) 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 writtennameCode
-copiedNode
-- Throws:
XPathException
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getActiveNamespaces
public NamespaceBinding[] 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:
- the set of namespace bindings.
- Throws:
XPathException
- if an error occurs
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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
- if a dynamic error occurs during the evaluation of the instruction
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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- 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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processLeft
public void processLeft(java.util.Stack<XPathContext> contextStack, java.util.Stack<java.lang.Object> state) throws XPathException
Process the first half of the instruction in streaming mode- Specified by:
processLeft
in interfaceDivisibleInstruction
- Overrides:
processLeft
in classElementCreator
- Parameters:
contextStack
- the dynamic evaluation contextstate
- a stack on which the instruction can save state information for use during the corresponding- Throws:
XPathException
- if a dynamic error occurs
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processRight
public void processRight(java.util.Stack<XPathContext> contextStack, java.util.Stack<java.lang.Object> state) throws XPathException
Process the second half of the instruction in streaming mode- Specified by:
processRight
in interfaceDivisibleInstruction
- Overrides:
processRight
in classElementCreator
- Parameters:
contextStack
- the stack of XPath context objects for the current execution statestate
- a stack on which the instruction can save state information for use during the corresponding- Throws:
XPathException
- if a dynamic error occurs
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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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