public final class ItemChecker extends UnaryExpression
operand
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
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ItemChecker(Expression sequence,
ItemType itemType,
RoleLocator role)
Constructor
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?????? | ????? |
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Expression |
copy()
Copy an expression.
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boolean |
equals(java.lang.Object other)
Is this expression the same as another expression?
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Item |
evaluateItem(XPathContext context)
Evaluate as an Item.
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void |
explain(ExpressionPresenter out)
Diagnostic print of expression structure.
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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
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ItemType |
getRequiredType()
Get the required type
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RoleLocator |
getRoleLocator()
Get the RoleLocator (used to construct error messages)
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SequenceIterator |
iterate(XPathContext context)
Iterate over the sequence of values
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void |
process(XPathContext context)
Process the instruction, without returning any tail calls
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Expression |
simplify(ExpressionVisitor visitor)
Simplify an expression
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Expression |
typeCheck(ExpressionVisitor visitor,
ItemType contextItemType)
Type-check the expression
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computeCardinality, computeSpecialProperties, displayExpressionName, displayOperator, getBaseExpression, hashCode, iterateSubExpressions, optimize, promote, replaceSubExpression, toString
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterateEvents, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
public ItemChecker(Expression sequence, ItemType itemType, RoleLocator role)
sequence
- the expression whose value we are checkingitemType
- the required type of the items in the sequencerole
- information used in constructing an error messagepublic ItemType getRequiredType()
public RoleLocator getRoleLocator()
public Expression simplify(ExpressionVisitor visitor) throws XPathException
simplify
??? UnaryExpression
visitor
- an expression visitorXPathException
- if an error is discovered during expression
rewritingpublic Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
typeCheck
??? UnaryExpression
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 int getImplementationMethod()
getImplementationMethod
??? Expression
Expression.ITERATE_METHOD
or Expression.EVALUATE_METHOD
or
Expression.PROCESS_METHOD
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
???? SequenceIterable
iterate
??? Expression
context
- supplies the context for evaluationXPathException
- if any dynamic error occurs evaluating the
expressionpublic Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
???? EvaluableItem
evaluateItem
??? Expression
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic void process(XPathContext context) throws XPathException
process
??? Expression
context
- The dynamic context, giving access to the current node,
the current variables, etc.XPathException
public Expression copy()
copy
??? Expression
public ItemType getItemType(TypeHierarchy th)
getItemType
??? UnaryExpression
th
- the type hierarchy cachepublic boolean equals(java.lang.Object other)
equals
??? UnaryExpression
public void explain(ExpressionPresenter out)
explain
??? UnaryExpression
out
- the expression presenter used to display the structure