public final class IsLastExpression extends Expression
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
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IsLastExpression(boolean condition)
Construct a condition that tests position() eq last() (if condition
is true) or position() ne last() (if condition is false).
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int |
computeCardinality()
Determine the static cardinality
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int |
computeSpecialProperties()
Determine the special properties of this expression
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Expression |
copy()
Copy an expression.
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Item |
evaluateItem(XPathContext c)
Evaluate an expression as a single item.
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void |
explain(ExpressionPresenter destination)
Diagnostic print of expression structure.
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boolean |
getCondition()
Get the condition we are testing for
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int |
getIntrinsicDependencies()
Get the dependencies of this expression on the context
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ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the expression
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Expression |
optimize(ExpressionVisitor visitor,
ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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Expression |
typeCheck(ExpressionVisitor visitor,
ItemType contextItemType)
Perform type checking of an expression and its subexpressions.
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addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterate, iterateEvents, iterateSubExpressions, markTailFunctionCalls, process, promote, replaceSubExpression, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, simplify, staticTypeCheck, suppressValidation, toString, typeError
public IsLastExpression(boolean condition)
condition
- true if we are testing "equals", false for "not equals".public boolean getCondition()
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType)
Expression
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.
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
public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType)
Expression
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.
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
public int computeSpecialProperties()
public Item evaluateItem(XPathContext c) throws XPathException
Expression
evaluateItem
???? EvaluableItem
evaluateItem
??? Expression
c
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic 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 int getIntrinsicDependencies()
getIntrinsicDependencies
??? Expression
public Expression copy()
copy
??? Expression
public void explain(ExpressionPresenter destination)
explain
??? Expression
destination
- the expression presenter used to display the structure