net.sf.saxon.expr
public class VennExpression extends BinaryExpression
Constructor Summary | |
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VennExpression(Expression p1, int op, Expression p2)
Constructor |
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). |
Expression | copy()
Copy an expression. |
boolean | effectiveBooleanValue(XPathContext context)
Get the effective boolean value. |
boolean | equals(Object other)
Is this expression the same as another expression? |
void | gatherComponents(int operator, Set set)
Gather the component operands of a union or intersect expression |
ItemType | getItemType(TypeHierarchy th)
Determine the data type of the items returned by this expression |
int | hashCode() |
SequenceIterator | iterate(XPathContext c)
Iterate over the value of the expression. |
Expression | optimize(ExpressionVisitor visitor, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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Expression | simplify(ExpressionVisitor visitor)
Simplify the expression |
Expression | typeCheck(ExpressionVisitor visitor, ItemType contextItemType)
Type-check the expression |
Parameters: p1 the left-hand operand op the operator (union, intersection, or difference) p2 the right-hand operand
Returns: the copy of the original expression
Parameters: operator union or intersect set the set into which the components are to be gathered. If the operator is union, this follows the tree gathering all operands of union expressions. Ditto, mutatis mutandis, for intersect expressions.
Parameters: th the type hierarchy cache
Returns: the data type
Parameters: c The context for evaluation
Returns: a SequenceIterator representing the union of the two operands
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: visitor an expression visitor 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.XPathException if an error is discovered during this phase (typically a type error)
Parameters: visitor an expression visitor