Class CopyOf
- All Implemented Interfaces:
Serializable
,SourceLocator
,Container
,Expression
,TailCallReturner
,InstructionInfoProvider
- See Also:
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Field Summary
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
ConstructorsConstructorDescriptionCopyOf
(Expression select, boolean copyNamespaces, int validation, SchemaType schemaType, boolean rejectDuplicatAttributes) -
Method Summary
Modifier and TypeMethodDescription(package private) static void
copyAttribute
(NodeInfo source, SchemaType 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
display
(int level, PrintStream out, Configuration config) Diagnostic print of expression structure.evaluateItem
(XPathContext context) Return the first item if there is one, or null if notint
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 instructioniterate
(XPathContext context) Return an Iterator to iterate over the values of a sequence.Get the immediate sub-expressions of this expression.optimize
(Optimizer opt, StaticContext env, ItemType 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
setReadOnce
(boolean b) void
setRequireDocumentOrElement
(boolean requireDocumentOrElement) For XQuery, the operand (select) must be a single element or document node.simplify
(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.Instruction
appendItem, assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, getInstructionInfo, getSourceLocator, isXSLT, process, promote
Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, getColumnNumber, getConstructType, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation, 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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CopyOf
public CopyOf(Expression select, boolean copyNamespaces, int validation, SchemaType schemaType, boolean rejectDuplicatAttributes)
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Method Details
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setReadOnce
public void setReadOnce(boolean b) -
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
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getInstructionNameCode
public int getInstructionNameCode()Get the name of this instruction, for diagnostics and tracing- Overrides:
getInstructionNameCode
in classInstruction
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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
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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.- Specified by:
getImplementationMethod
in interfaceExpression
- Overrides:
getImplementationMethod
in classInstruction
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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
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copyAttribute
static void copyAttribute(NodeInfo source, SchemaType 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
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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 interfaceExpression
- Specified by:
simplify
in classInstruction
- Parameters:
env
- the static context- 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- Specified by:
getItemType
in interfaceExpression
- Overrides:
getItemType
in classInstruction
- Parameters:
th
-- Returns:
- the static item type of the instruction
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getCardinality
public int getCardinality()Description copied from class:ComputedExpression
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.- Specified by:
getCardinality
in interfaceExpression
- Overrides:
getCardinality
in classComputedExpression
- 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:ComputedExpression
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.- Specified by:
getDependencies
in interfaceExpression
- Overrides:
getDependencies
in classComputedExpression
- 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
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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.
- 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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optimize
public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException Description copied from interface: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.
- Parameters:
opt
- the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.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 if appropriate to optimize execution
- Throws:
XPathException
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display
Diagnostic print of expression structure. The expression is written to the System.err output stream- Parameters:
level
- indentation level for this expressionout
-config
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iterateSubExpressions
Description copied from class:ComputedExpression
Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.- Specified by:
iterateSubExpressions
in interfaceExpression
- Overrides:
iterateSubExpressions
in classComputedExpression
- 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 classComputedExpression
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression- Returns:
- true if the original subexpression is found
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evaluateItem
Return the first item if there is one, or null if not- Specified by:
evaluateItem
in interfaceExpression
- Overrides:
evaluateItem
in classInstruction
- Parameters:
context
-- Returns:
- the result of evaluating the instruction
- Throws:
XPathException
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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.- Specified by:
iterate
in interfaceExpression
- 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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