public class ForExpression extends Assignation
action, requiredType, sequence, slotNumber, variableName
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
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ForExpression()
Create a "for" expression (for $x at $p in SEQUENCE return ACTION)
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void |
checkPermittedContents(SchemaType parentType,
StaticContext env,
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.
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int |
computeCardinality()
Determine the static cardinality of the expression
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Expression |
convertWhereToPredicate(ExpressionVisitor visitor,
ItemType contextItemType)
Convert where clause, if possible, to a predicate.
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Expression |
copy()
Copy an expression.
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void |
evaluatePendingUpdates(XPathContext context,
PendingUpdateList pul)
Evaluate an updating expression, adding the results to a Pending Update List.
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void |
explain(ExpressionPresenter out)
Diagnostic print of expression structure.
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protected Binding[] |
extendBindingList(Binding[] in)
Extend an array of variable bindings to include the binding(s) defined in this expression
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int |
getConstructType()
Get the type of this expression for use in tracing and diagnostics
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int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
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ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the items returned by the expression, if possible
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StructuredQName |
getPositionVariableName()
Get the name of the position variable
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int |
getRequiredSlots()
Get the number of slots required.
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boolean |
hasLoopingSubexpression(Expression child)
Given an expression that is an immediate child of this expression, test whether
the evaluation of the parent expression causes the child expression to be
evaluated repeatedly
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SequenceIterator |
iterate(XPathContext context)
Iterate over the sequence of values
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EventIterator |
iterateEvents(XPathContext context)
Deliver the result of the expression as a sequence of events.
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int |
markTailFunctionCalls(StructuredQName qName,
int arity)
Mark tail function calls: only possible if the for expression iterates zero or one times.
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Expression |
optimize(ExpressionVisitor visitor,
ItemType contextItemType)
Optimize the expression
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void |
process(XPathContext context)
Process this expression as an instruction, writing results to the current
outputter
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void |
setPositionVariable(PositionVariable decl)
Set the reference to the position variable (XQuery only)
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void |
setSlotNumber(int nr)
Set the slot number for the range variable
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Expression |
typeCheck(ExpressionVisitor visitor,
ItemType contextItemType)
Type-check the expression
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addToPathMap, checkForUpdatingSubexpressions, evaluateVariable, getAction, getLocalSlotNumber, getObjectName, getRequiredType, getSequence, getVariableName, getVariableQName, isAssignable, isGlobal, isUpdatingExpression, iterateSubExpressions, promote, promoteWhereClause, refineTypeInformation, replaceSubExpression, setAction, setRequiredType, setSequence, setVariableQName, simplify, suppressValidation
adoptChildExpression, computeDependencies, computeSpecialProperties, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getContainer, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, implementsStaticTypeCheck, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, toString, typeError
public ForExpression()
public void setPositionVariable(PositionVariable decl)
decl
- the range variable declaration for the position variablepublic StructuredQName getPositionVariableName()
public void setSlotNumber(int nr)
setSlotNumber
??? Assignation
nr
- the slot number allocated to the range variable on the local stack frame.
This implicitly allocates the next slot number to the position variable if there is one.public int getRequiredSlots()
getRequiredSlots
??? Assignation
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
typeCheck
??? Expression
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 to
Type.ITEM_TYPE
XPathException
- if an error is discovered during this phase
(typically a type error)public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
optimize
??? Expression
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 to
Type.ITEM_TYPE
XPathException
- if an error is discovered during this phase
(typically a type error)public boolean hasLoopingSubexpression(Expression child)
hasLoopingSubexpression
??? Expression
child
- the immediate subexpressionpublic Expression convertWhereToPredicate(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
visitor
- the expression visitorcontextItemType
- the item type of the context itemXPathException
public Expression copy()
copy
??? Expression
public int markTailFunctionCalls(StructuredQName qName, int arity)
markTailFunctionCalls
??? Expression
qName
- the name of the functionarity
- the arity (number of parameters) of the functionprotected Binding[] extendBindingList(Binding[] in)
extendBindingList
??? Assignation
in
- a set of variable bindingspublic int getImplementationMethod()
getImplementationMethod
??? Expression
Expression.ITERATE_METHOD
or Expression.EVALUATE_METHOD
or
Expression.PROCESS_METHOD
public void checkPermittedContents(SchemaType parentType, StaticContext env, boolean whole) throws XPathException
checkPermittedContents
??? Expression
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 typeenv
- the static contextwhole
- 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 contentXPathException
- if the value delivered by this expression cannot be part of the content model
of the given typepublic SequenceIterator iterate(XPathContext context) throws XPathException
iterate
???? SequenceIterable
iterate
??? Expression
context
- supplies the context for evaluationXPathException
- if any dynamic error occurs evaluating the
expressionpublic EventIterator iterateEvents(XPathContext context) throws XPathException
iterateEvents
??? Expression
context
- The dynamic evaluation contextXPathException
- if a dynamic error occurs during expression evaluationpublic void process(XPathContext context) throws XPathException
process
??? Expression
context
- The dynamic context, giving access to the current node,
the current variables, etc.XPathException
public void evaluatePendingUpdates(XPathContext context, PendingUpdateList pul) throws XPathException
evaluatePendingUpdates
??? Expression
context
- the XPath dynamic evaluation contextpul
- the pending update list to which the results should be writtenXPathException
public ItemType getItemType(TypeHierarchy th)
getItemType
??? Expression
th
- the type hierarchy cachepublic int computeCardinality()
computeCardinality
??? Expression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public void explain(ExpressionPresenter out)
explain
??? Expression
out
- the expression presenter used to display the structurepublic int getConstructType()
getConstructType
???? InstructionInfo
getConstructType
??? Expression
Location