net.sf.saxon.functions
Class Existence
- EvaluableItem, InstructionInfoProvider, Negatable, SequenceIterable, Serializable, SourceLocator
Implement the exists() and empty() functions *
addContextDocumentArgument , addDocToPathMap , checkArguments , computeCardinality , computeSpecialProperties , copy , getDetails , getErrorCodeForTypeErrors , getItemType , getRequiredType , makeSystemFunction , optimize , setDetails , useContextItemAsDefault |
addExternalFunctionCallToPathMap , checkArgumentCount , checkArguments , equals , explain , getArguments , getDisplayName , getFunctionName , getNumberOfArguments , hashCode , iterateSubExpressions , optimize , preEvaluate , promote , replaceSubExpression , setArguments , setFunctionName , simplify , simplifyArguments , toString , typeCheck |
addToPathMap , adoptChildExpression , checkPermittedContents , computeCardinality , computeDependencies , computeSpecialProperties , computeStaticProperties , copy , display , doPromotion , dynamicError , effectiveBooleanValue , evaluateAsString , evaluateItem , explain , explain , findParentOf , getCardinality , getColumnNumber , getConstructType , getContainer , getDependencies , getExecutable , getHostLanguage , getImplementationMethod , getInstructionInfo , getIntrinsicDependencies , getItemType , getLineNumber , getLocationId , getLocationProvider , getPublicId , getSlotsUsed , getSpecialProperties , getSystemId , hasLoopingSubexpression , implementsStaticTypeCheck , iterate , iterateEvents , iterateSubExpressions , markTailFunctionCalls , optimize , process , promote , replaceSubExpression , resetLocalStaticProperties , setContainer , setFiltered , setFlattened , setLocationId , simplify , staticTypeCheck , suppressValidation , toString , typeCheck , typeError |
EMPTY
public static final int EMPTY
EXISTS
public static final int EXISTS
negate
public Expression negate()
Return the negation of the expression
- negate in interface Negatable
- the negation of the expression
optimize
public Expression optimize(ExpressionVisitor visitor,
ItemType contextItemType)
throws XPathException
Perform optimisation of an expression and its subexpressions.
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 in interface SystemFunction
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
- the original expression, rewritten if appropriate to optimize execution
XPathException
- if an error is discovered during this phase
(typically a type error)