Class CopyOf
- All Implemented Interfaces:
Serializable
,SourceLocator
,LocationProvider
,SaxonLocator
,TailCallReturner
,ValidatingInstruction
,InstructionInfo
,Locator
- See Also:
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Field Summary
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
ConstructorsConstructorDescriptionCopyOf
(Expression select, boolean copyNamespaces, int validation, SchemaType schemaType, boolean rejectDuplicateAttributes) Create an xsl:copy-of instruction (also used in XQuery for implicit copying) -
Method Summary
Modifier and TypeMethodDescriptionaddToPathMap
(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) Add a representation of this expression to a PathMap.copy()
Copy an expression.(package private) static void
copyAttribute
(NodeInfo source, SimpleType schemaType, int validation, Instruction instruction, XPathContext context, boolean rejectDuplicates) Method shared by xsl:copy and xsl:copy-of to copy an attribute nodefinal boolean
Determine whether this instruction creates new nodes.void
Diagnostic print of expression structure.int
Determine the static cardinality of the expression.int
Determine which aspects of the context the expression depends on.int
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().int
Get the name of this instruction, for diagnostics and tracingGet the item type of the items returned by evaluating this instructionGet the schema type to be used for validationGet the expression that selects the nodes to be copiedint
Get the validation modeboolean
Ask whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)boolean
Determine whether namespaces are to be copied or notboolean
Test whether this expression requires a document or element nodeboolean
Test if the instruction is doing validationSequenceIterator
<? extends Item> iterate
(XPathContext context) Return an Iterator to iterate over the values of a sequence.Get the immediate sub-expressions of this expression.optimize
(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) Perform optimisation of an expression and its subexpressions.processLeavingTail
(XPathContext context) Process this xsl:copy-of instructionprotected 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 subexpressionvoid
setCopyForUpdate
(boolean forUpdate) Set whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)void
setCopyLineNumbers
(boolean copy) Set whether line numbers are to be copied from the source to the result.void
setReadOnce
(boolean b) Set the "saxon:read-once" optimization modevoid
setRequireDocumentOrElement
(boolean requireDocumentOrElement) For XQuery, the operand (select) must be a single element or document node.void
setStaticBaseUri
(String base) Set the static base URI of the xsl:copy-of instructionsimplify
(ExpressionVisitor visitor) Simplify an 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.Instruction
assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getConstructType, getExpressionName, getInstructionName, getIteratorFromProcessMethod, getSourceLocator, isXSLT, process, promote
Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getColumnNumber, getColumnNumber, getContainer, getEvaluationMethod, getExecutable, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, 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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CopyOf
public CopyOf(Expression select, boolean copyNamespaces, int validation, SchemaType schemaType, boolean rejectDuplicateAttributes) Create an xsl:copy-of instruction (also used in XQuery for implicit copying)- Parameters:
select
- expression that selects the nodes to be copiedcopyNamespaces
- true if namespaces are to be copiedvalidation
- validation mode for the result treeschemaType
- schema type for validating the result treerejectDuplicateAttributes
- true if duplicate attributes are to be rejected (XQuery). False if duplicates are handled by discarding all but the first (XSLT).
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Method Details
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getSelectExpression
Get the expression that selects the nodes to be copied- Returns:
- the select expression
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getValidationAction
public int getValidationAction()Get the validation mode- Specified by:
getValidationAction
in interfaceValidatingInstruction
- Returns:
- the validation mode
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isValidating
public boolean isValidating()Test if the instruction is doing validation- Returns:
- true if it is
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getSchemaType
Get the schema type to be used for validation- Specified by:
getSchemaType
in interfaceValidatingInstruction
- Returns:
- the schema type, or null if not validating against a type
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setStaticBaseUri
Set the static base URI of the xsl:copy-of instruction- Parameters:
base
- the static base URI
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setReadOnce
public void setReadOnce(boolean b) Set the "saxon:read-once" optimization mode- Parameters:
b
- true to enable the optimization
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setCopyLineNumbers
public void setCopyLineNumbers(boolean copy) Set whether line numbers are to be copied from the source to the result. Default is false.- Parameters:
copy
- true if line numbers are to be copied
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createsNewNodes
public final boolean createsNewNodes()Determine whether this instruction creates new nodes. The result depends on the type of the select expression.- Overrides:
createsNewNodes
in classInstruction
- Returns:
- true if the instruction creates new nodes (or if it can't be proved that it doesn't)
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getInstructionNameCode
public int getInstructionNameCode()Get the name of this instruction, for diagnostics and tracing- 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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setRequireDocumentOrElement
public void setRequireDocumentOrElement(boolean requireDocumentOrElement) For XQuery, the operand (select) must be a single element or document node.- Parameters:
requireDocumentOrElement
- true if the argument must be a single element or document node
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isDocumentOrElementRequired
public boolean isDocumentOrElementRequired()Test whether this expression requires a document or element node- Returns:
- true if this expression requires the value of the argument to be a document or element node, false if there is no such requirement
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setCopyForUpdate
public void setCopyForUpdate(boolean forUpdate) Set whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)- Parameters:
forUpdate
- true if this copy is being created to support an update
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isCopyForUpdate
public boolean isCopyForUpdate()Ask whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)- Returns:
- true if this copy is being created to support an update
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getImplementationMethod
public int getImplementationMethod()An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided. This implementation provides both iterate() and process() methods natively.- Overrides:
getImplementationMethod
in classInstruction
- Returns:
- the implementation method, for example
Expression.ITERATE_METHOD
orExpression.EVALUATE_METHOD
orExpression.PROCESS_METHOD
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isCopyNamespaces
public boolean isCopyNamespaces()Determine whether namespaces are to be copied or not- Returns:
- true if namespaces are to be copied (the default)
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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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simplify
Description copied from class:Instruction
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 classInstruction
- Parameters:
visitor
- an expression visitor- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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getItemType
Description copied from class:Instruction
Get the item type of the items returned by evaluating this instruction- Overrides:
getItemType
in classInstruction
- Parameters:
th
- the type hierarchy cache- Returns:
- the static item type of the instruction
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getCardinality
public int getCardinality()Description copied from class:Expression
Determine the static cardinality of the expression. This establishes how many items there will be in the result of the expression, at compile time (i.e., without actually evaluating the result.- Overrides:
getCardinality
in classExpression
- Returns:
- one of the values Cardinality.ONE_OR_MORE, Cardinality.ZERO_OR_MORE, Cardinality.EXACTLY_ONE, Cardinality.ZERO_OR_ONE, Cardinality.EMPTY. This default implementation returns ZERO_OR_MORE (which effectively gives no information).
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getDependencies
public int getDependencies()Description copied from class:Expression
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:
getDependencies
in classExpression
- Returns:
- a set of bit-significant flags identifying the dependencies of the expression
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promoteInst
Description copied from class:Instruction
Handle promotion offers, that is, non-local tree rewrites.- Overrides:
promoteInst
in classInstruction
- Parameters:
offer
- The type of rewrite being offered- Throws:
XPathException
- if an error occurs
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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 classExpression
- 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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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 classExpression
- 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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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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iterateSubExpressions
Description copied from class:Expression
Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.- Overrides:
iterateSubExpressions
in classExpression
- Returns:
- an iterator containing the sub-expressions of this expression
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replaceSubExpression
Replace one subexpression by a replacement subexpression- Overrides:
replaceSubExpression
in classExpression
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression- Returns:
- true if the original subexpression is found
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addToPathMap
Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.
- Overrides:
addToPathMap
in classExpression
- Parameters:
pathMap
- the PathMap to which the expression should be addedpathMapNodeSet
- the PathMapNodeSet to which the paths embodied in this expression should be added- Returns:
- the pathMapNodeSet representing the points in the source document that are both reachable by this expression, and that represent possible results of this expression. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.
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processLeavingTail
Process this xsl:copy-of instruction- Specified by:
processLeavingTail
in interfaceTailCallReturner
- Specified by:
processLeavingTail
in classInstruction
- Parameters:
context
- the dynamic context for the transformation- Returns:
- null - this implementation of the method never returns a TailCall
- Throws:
XPathException
- if a dynamic error occurs during the evaluation of the instruction
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copyAttribute
static void copyAttribute(NodeInfo source, SimpleType schemaType, int validation, Instruction instruction, XPathContext context, boolean rejectDuplicates) throws XPathException Method shared by xsl:copy and xsl:copy-of to copy an attribute node- Parameters:
source
- the node to be copiedschemaType
- the simple type against which the value is to be validated, if anyvalidation
- one of preserve, strip, strict, laxinstruction
- the calling instruction, used for diagnosticscontext
- the dynamic contextrejectDuplicates
- true if duplicate attributes with the same name are disallowed (XQuery)- Throws:
XPathException
- if a failure occurs
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iterate
Description copied from class:Instruction
Return an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.- Overrides:
iterate
in classInstruction
- Parameters:
context
- supplies the context for evaluation- Returns:
- a SequenceIterator that can be used to iterate over the result of the expression
- Throws:
XPathException
- if any dynamic error occurs evaluating the expression
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