net.sf.saxon.expr
public abstract class UnaryExpression extends ComputedExpression
Field Summary | |
---|---|
protected Expression | operand |
Constructor Summary | |
---|---|
UnaryExpression(Expression p0) |
Method Summary | |
---|---|
int | computeCardinality()
Determine the static cardinality. |
int | computeSpecialProperties()
Get the static properties of this expression (other than its type). |
void | display(int level, NamePool pool, PrintStream out)
Diagnostic print of expression structure |
protected abstract String | displayOperator(NamePool pool)
Give a string representation of the operator for use in diagnostics |
boolean | equals(Object other)
Is this expression the same as another expression? |
Expression | getBaseExpression() |
ItemType | getItemType(TypeHierarchy th)
Determine the data type of the expression, if possible. |
int | hashCode()
get HashCode for comparing two expressions. |
Iterator | iterateSubExpressions()
Get the immediate subexpressions of this expression |
Expression | optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
|
Expression | promote(PromotionOffer offer)
Promote this expression if possible |
Expression | simplify(StaticContext env)
Simplify an expression |
Expression | typeCheck(StaticContext env, ItemType contextItemType)
Type-check the expression. |
Returns: the operator, as a string
Parameters: th
Returns: the item type of the items in the result sequence, insofar as this is known statically.
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