Class GeneralVariable
- All Implemented Interfaces:
Serializable
,SourceLocator
,Binding
,Container
,Expression
,TailCallReturner
,InstructionInfoProvider
- Direct Known Subclasses:
Assign
,GlobalVariable
,LocalParam
,LocalVariable
,SQLColumn.ColumnInstruction
,WithParam
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected int
protected int
protected int
(package private) SequenceType
(package private) Expression
protected int
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
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
display
(int level, PrintStream out, Configuration config) Diagnostic print of expression structure.evaluateItem
(XPathContext context) Evaluate an expression as a single item.int
Get the cardinality of the result of this instruction.int
Get the namecode of the instruction for use in diagnosticsGet the type of the result of this instruction.int
If this is a local variable held on the local stack frame, return the corresponding slot number.int
getSelectValue
(XPathContext context) Evaluate the variable.int
int
Get the name of the variable (as a NamePool fingerprint)void
init
(Expression select, int nameCode) final boolean
Test whether it is permitted to assign to the variable using the saxon:assign extension element.boolean
isGlobal()
Indicate whether the binding is local or global.final boolean
final boolean
final boolean
iterate
(XPathContext context) Return an Iterator to iterate over the values of a sequence.Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)optimize
(Optimizer opt, StaticContext env, ItemType contextItemType) Perform optimisation of an expression and its subexpressions.protected 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
setAssignable
(boolean assignable) void
setImplicitlyRequiredParam
(boolean requiredParam) void
setNameCode
(int nameCode) void
setReferenceCount
(int refCount) void
setRequiredParam
(boolean requiredParam) void
setRequiredType
(SequenceType required) void
setSelectExpression
(Expression select) void
setSlotNumber
(int s) void
setTunnel
(boolean tunnel) void
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, createsNewNodes, dynamicError, evaluateAsString, getImplementationMethod, getInstructionInfo, getSourceLocator, isXSLT, process, processLeavingTail, promote
Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, getColumnNumber, getConstructType, getDependencies, 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 net.sf.saxon.expr.Binding
evaluateVariable
Methods inherited from interface javax.xml.transform.SourceLocator
getColumnNumber, getLineNumber, getPublicId, getSystemId
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Field Details
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select
Expression select -
nameCode
protected int nameCode -
requiredType
SequenceType requiredType -
slotNumber
protected int slotNumber -
referenceCount
protected int referenceCount -
evaluationMode
protected int evaluationMode
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Constructor Details
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GeneralVariable
public GeneralVariable()
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Method Details
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init
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setSelectExpression
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getSelectExpression
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setRequiredType
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getRequiredType
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setNameCode
public void setNameCode(int nameCode) -
getNameCode
public int getNameCode() -
setAssignable
public void setAssignable(boolean assignable) -
setRequiredParam
public void setRequiredParam(boolean requiredParam) -
setImplicitlyRequiredParam
public void setImplicitlyRequiredParam(boolean requiredParam) -
setTunnel
public void setTunnel(boolean tunnel) -
setReferenceCount
public void setReferenceCount(int refCount) -
isAssignable
public final boolean isAssignable()Test whether it is permitted to assign to the variable using the saxon:assign extension element. This will only be true if the extra attribute saxon:assignable="yes" is present.- Specified by:
isAssignable
in interfaceBinding
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getVariableFingerprint
public int getVariableFingerprint()Get the name of the variable (as a NamePool fingerprint)- Returns:
- the NamePool fingerprint of the variable's expanded name.
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getItemType
Get the type of the result of this instruction. An xsl:variable instruction returns nothing, so the type is empty.- Specified by:
getItemType
in interfaceExpression
- Overrides:
getItemType
in classInstruction
- Parameters:
th
-- Returns:
- the empty type.
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getCardinality
public int getCardinality()Get the cardinality of the result of this instruction. An xsl:variable instruction returns nothing, so the type is empty.- Specified by:
getCardinality
in interfaceExpression
- Overrides:
getCardinality
in classComputedExpression
- Returns:
- the empty cardinality.
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isGlobal
public boolean isGlobal()Description copied from interface:Binding
Indicate whether the binding is local or global. A global binding is one that has a fixed value for the life of a query or transformation; any other binding is local. -
getLocalSlotNumber
public int getLocalSlotNumber()If this is a local variable held on the local stack frame, return the corresponding slot number. In other cases, return -1.- Specified by:
getLocalSlotNumber
in interfaceBinding
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isRequiredParam
public final boolean isRequiredParam() -
isImplicitlyRequiredParam
public final boolean isImplicitlyRequiredParam() -
isTunnelParam
public final boolean isTunnelParam() -
getInstructionNameCode
public int getInstructionNameCode()Description copied from class:Instruction
Get the namecode of the instruction for use in diagnostics- Overrides:
getInstructionNameCode
in classInstruction
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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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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.
- Specified by:
typeCheck
in interfaceExpression
- 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.
- Specified by:
optimize
in interfaceExpression
- 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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evaluateItem
Evaluate an expression as a single item. This always returns either a single Item or null (denoting the empty sequence). No conversion is done. This method should not be used unless the static type of the expression is a subtype of "item" or "item?": that is, it should not be called if the expression may return a sequence. There is no guarantee that this condition will be detected.- Specified by:
evaluateItem
in interfaceExpression
- Overrides:
evaluateItem
in classInstruction
- 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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iterate
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 relies on the process() method: it "pushes" the results of the instruction to a sequence in memory, and then iterates over this in-memory sequence. In principle instructions should implement a pipelined iterate() method that avoids the overhead of intermediate storage.- 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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getSelectValue
Evaluate the variable. That is, get the value of the select expression if present or the content of the element otherwise, either as a tree or as a sequence- Throws:
XPathException
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promoteInst
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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iterateSubExpressions
Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)- 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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display
Diagnostic print of expression structure. The expression is written to the System.err output stream- Specified by:
display
in interfaceExpression
- Parameters:
level
- indentation level for this expressionout
-config
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getSlotNumber
public int getSlotNumber() -
setSlotNumber
public void setSlotNumber(int s) -
setVariableName
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getVariableName
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