Package net.sf.saxon.expr.instruct
Class IterateInstr
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.expr.instruct.Instruction
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- net.sf.saxon.expr.instruct.IterateInstr
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- All Implemented Interfaces:
ContextOriginator,ContextSwitchingExpression,ExportAgent,TailCallReturner,Locatable,IdentityComparable,Traceable
public final class IterateInstr extends Instruction implements ContextSwitchingExpression
An IterateInstr is the compiled form of an xsl:iterate instruction
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Field Summary
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Fields inherited from class net.sf.saxon.expr.Expression
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_COST, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD
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Constructor Summary
Constructors Constructor Description IterateInstr(Expression select, LocalParamBlock initiallyExp, Expression action, Expression onCompletion)Create an xsl:iterate instruction
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description voidcheckPermittedContents(SchemaType parentType, boolean whole)Check that any elements and attributes constructed or returned by this expression are acceptable in the content model of a given complex type.Expressioncopy(RebindingMap rebindings)Copy an expression.voidexport(ExpressionPresenter out)Diagnostic print of expression structure.ExpressiongetActionExpression()Get the action expression (the content of the xsl:iterate)intgetImplementationMethod()An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().LocalParamBlockgetInitiallyExp()intgetInstructionNameCode()Get the namecode of the instruction for use in diagnosticsItemTypegetItemType()Determine the data type of the items returned by this expressionExpressiongetOnCompletion()ExpressiongetSelectExpression()Get the select expression (the select attribute of the xsl:iterate)java.lang.StringgetStreamerName()Get the (partial) name of a class that supports streaming of this kind of expressionbooleanhasVariableBinding(Binding binding)Ask whether this expression is, or contains, the binding of a given variablebooleanisCompilable()Test whether it is possible to generate byte-code for the instruction.booleanmayCreateNewNodes()Determine whether this instruction creates new nodes.java.lang.Iterable<Operand>operands()Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression.Expressionoptimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)Perform optimisation of an expression and its subexpressions.TailCallprocessLeavingTail(Outputter output, XPathContext context)ProcessLeavingTail: called to do the real work of this instruction.voidsetAction(Expression action)voidsetInitiallyExp(LocalParamBlock initiallyExp)voidsetOnCompletion(Expression onCompletion)voidsetSelect(Expression select)ExpressiontypeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)Type-check the expression-
Methods inherited from class net.sf.saxon.expr.instruct.Instruction
alwaysCreatesNewNodes, assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getExpressionName, getNetCost, getSourceLocator, isInstruction, isXSLT, iterate, process, someOperandCreatesNewNodes
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Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, computeDependencies, computeHashCode, computeStaticProperties, dynamicError, effectiveBooleanValue, equals, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, getTracingTag, hasCompatibleStaticContext, hashCode, hasSpecialProperty, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isLiftable, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, prepareForStreaming, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, toShortString, toString, typeCheckChildren, typeError, unordered, verifyParentPointers
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface net.sf.saxon.trace.Traceable
gatherProperties
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Constructor Detail
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IterateInstr
public IterateInstr(Expression select, LocalParamBlock initiallyExp, Expression action, Expression onCompletion)
Create an xsl:iterate instruction- Parameters:
select- the select expressioninitiallyExp- the initialization of the xsl:param elementsaction- the body of the xsl:iterate looponCompletion- the expression to be evaluated before final completion, may be null
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Method Detail
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setSelect
public void setSelect(Expression select)
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getInitiallyExp
public LocalParamBlock getInitiallyExp()
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setInitiallyExp
public void setInitiallyExp(LocalParamBlock initiallyExp)
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setAction
public void setAction(Expression action)
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getOnCompletion
public Expression getOnCompletion()
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setOnCompletion
public void setOnCompletion(Expression onCompletion)
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operands
public java.lang.Iterable<Operand> operands()
Description copied from class:ExpressionGet the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression. Default implementation works off the results of iterateSubExpressions()If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.
- Specified by:
operandsin classInstruction- Returns:
- an iterator containing the sub-expressions of this expression
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getInstructionNameCode
public int getInstructionNameCode()
Get the namecode of the instruction for use in diagnostics- Overrides:
getInstructionNameCodein classInstruction- Returns:
- a code identifying the instruction: typically but not always the fingerprint of a name in the XSLT namespace
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getSelectExpression
public Expression getSelectExpression()
Get the select expression (the select attribute of the xsl:iterate)- Specified by:
getSelectExpressionin interfaceContextSwitchingExpression- Returns:
- the select expression
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getActionExpression
public Expression getActionExpression()
Get the action expression (the content of the xsl:iterate)- Specified by:
getActionExpressionin interfaceContextSwitchingExpression- Returns:
- the body of the xsl:iterate loop
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
Type-check the expression- Overrides:
typeCheckin classExpression- Parameters:
visitor- an expression visitorcontextInfo- Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.- 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, ContextItemStaticInfo contextInfo) throws XPathException
Description copied from class:ExpressionPerform 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:
optimizein classExpression- Parameters:
visitor- an expression visitorcontextInfo- 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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isCompilable
public boolean isCompilable()
Test whether it is possible to generate byte-code for the instruction. This is not possible unless any xsl:break or xsl:next-iteration instructions are part of the same compilation unit, which is not the case if they appear within a try-catch.- Returns:
- true if the instruction does not contain an xsl:break or xsl:next-iteration instruction within a try/catch block
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getItemType
public final ItemType getItemType()
Determine the data type of the items returned by this expression- Overrides:
getItemTypein classInstruction- Returns:
- the data type
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mayCreateNewNodes
public final boolean mayCreateNewNodes()
Determine whether this instruction creates new nodes. This implementation returns true if the "action" creates new nodes. (Nodes created by the condition can't contribute to the result).- Overrides:
mayCreateNewNodesin classInstruction- Returns:
- true if the instruction creates new nodes under some input conditions (or if it can't be proved that it doesn't)
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hasVariableBinding
public boolean hasVariableBinding(Binding binding)
Ask whether this expression is, or contains, the binding of a given variable- Overrides:
hasVariableBindingin classExpression- Parameters:
binding- the variable binding- Returns:
- true if this expression is the variable binding (for example a ForExpression or LetExpression) or if it is a FLWOR expression that binds the variable in one of its clauses.
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getStreamerName
public java.lang.String getStreamerName()
Get the (partial) name of a class that supports streaming of this kind of expression- Overrides:
getStreamerNamein classExpression- Returns:
- the partial name of a class that can be instantiated to provide streaming support in Saxon-EE, or null if there is no such class
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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:
getImplementationMethodin classInstruction- Returns:
- the implementation method, for example
Expression.ITERATE_METHODorExpression.EVALUATE_METHODorExpression.PROCESS_METHOD
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checkPermittedContents
public void checkPermittedContents(SchemaType parentType, boolean whole) throws XPathException
Check that any elements and attributes constructed or returned by this expression are acceptable in the content model of a given complex type. It's always OK to say yes, since the check will be repeated at run-time. The process of checking element and attribute constructors against the content model of a complex type also registers the type of content expected of those constructors, so the static validation can continue recursively.- Overrides:
checkPermittedContentsin classExpression- Parameters:
parentType- the "given complex type": the method is checking that the nodes returned by this expression are acceptable members of the content model of this typewhole- if true, we want to check that the value of this expression satisfies the content model as a whole; if false we want to check that the value of the expression is acceptable as one part of the content- Throws:
XPathException- if the value delivered by this expression cannot be part of the content model of the given type
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copy
public Expression copy(RebindingMap rebindings)
Copy an expression. This makes a deep copy.- Specified by:
copyin classExpression- Parameters:
rebindings- a mutable list of (old binding, new binding) pairs that is used to update the bindings held in any local variable references that are copied.- Returns:
- the copy of the original expression
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processLeavingTail
public TailCall processLeavingTail(Outputter output, XPathContext context) throws XPathException
Description copied from class:InstructionProcessLeavingTail: called to do the real work of this instruction. This method must be implemented in each subclass. The results of the instruction are written to the current Receiver, which can be obtained via the Controller.- Specified by:
processLeavingTailin interfaceTailCallReturner- Specified by:
processLeavingTailin classInstruction- Parameters:
output- the destination for the resultcontext- The dynamic context of the transformation, giving access to the current node, the current variables, etc.- Returns:
- null if the instruction has completed execution; or a TailCall indicating a function call or template call that is delegated to the caller, to be made after the stack has been unwound so as to save stack space.
- Throws:
XPathException- if a dynamic error occurs during the evaluation of the instruction
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export
public void export(ExpressionPresenter out) throws XPathException
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Specified by:
exportin interfaceExportAgent- Specified by:
exportin classExpression- Parameters:
out- the expression presenter used to display the structure- Throws:
XPathException- if the export fails, for example if an expression is found that won't work in the target environment.
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