net.sf.saxon.expr
public final class CardinalityChecker extends UnaryExpression
Method Summary | |
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int | computeCardinality()
Determine the static cardinality of the expression |
int | computeSpecialProperties()
Get the static properties of this expression (other than its type). |
String | displayOperator(NamePool pool)
Diagnostic print of expression structure |
boolean | equals(Object other)
Is this expression the same as another expression? |
Item | evaluateItem(XPathContext context)
Evaluate as an Item. |
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 |
int | getRequiredCardinality()
Get the required cardinality |
SequenceIterator | iterate(XPathContext context)
Iterate over the sequence of values |
static ComputedExpression | makeCardinalityChecker(Expression sequence, int cardinality, RoleLocator role)
Factory method to construct a CardinalityChecker. |
Expression | optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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void | process(XPathContext context)
Process the instruction, without returning any tail calls
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void | setErrorCode(String code)
Set the error code to be returned (this is used when evaluating the functions such
as exactly-one() which have their own error codes) |
Expression | typeCheck(StaticContext env, ItemType contextItemType)
Type-check the expression |
Parameters: th
Returns: a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known in advance)
Parameters: sequence cardinality role
Returns: a new Expression that does the CardinalityChecking (not necessarily a CardinalityChecker)
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.
Parameters: opt the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances. env the static context of the expression contextItemType 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 ITEM_TYPE
Returns: the original expression, rewritten if appropriate to optimize execution
Throws: net.sf.saxon.trans.StaticError if an error is discovered during this phase (typically a type error)
Parameters: context The dynamic context, giving access to the current node, the current variables, etc.