net.sf.saxon.expr
public final class PositionRange extends ComputedExpression
Constructor Summary | |
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PositionRange(Expression min, Expression max)
Create a position range | |
PositionRange(int min, int max)
Create a constant position range |
Method Summary | |
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int | computeCardinality()
Determine the static cardinality |
int | computeSpecialProperties()
Determine the special properties of this expression |
void | display(int level, NamePool pool, PrintStream out)
Diagnostic print of expression structure |
Item | evaluateItem(XPathContext c)
Evaluate the expression |
int | getIntrinsicDependencies()
Get the dependencies |
ItemType | getItemType(TypeHierarchy th)
Determine the data type of the expression |
boolean | hasFocusDependentRange()
Test whether the range is focus-dependent. |
boolean | isFirstPositionOnly()
Test if the first and last position are both constant 1 |
Iterator | iterateSubExpressions()
Get the immediate sub-expressions of this expression. |
SequenceIterator | makePositionIterator(SequenceIterator base, XPathContext c)
Make an iterator over a range of a sequence determined by this position range |
TailExpression | makeTailExpression(Expression start)
If this is an open-ended range with a constant start position, make a TailExpression.
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boolean | matchesAtMostOneItem()
Test if the position range matches at most one item |
Expression | optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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Expression | simplify(StaticContext env)
Simplify an expression |
Expression | typeCheck(StaticContext env, ItemType contextItemType)
Type-check the expression |
Returns: NON_CREATIVE.
Parameters: th
Returns: Type.BOOLEAN
Returns: an iterator containing the sub-expressions of this 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.
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)
Returns: the simplified expression