net.sf.saxon.expr

Interface Negatable

public interface Negatable

This interface is implemented by expressions that returns a boolean value, and returns an expression whose result is the negated boolean value

Method Summary
boolean	isNegatable(ExpressionVisitor visitor) Check whether this specific instance of the expression is negatable
Expression	negate() Create an expression that returns the negation of this expression

Method Detail

public boolean isNegatable(ExpressionVisitor visitor)

Check whether this specific instance of the expression is negatable

Returns: true if it is

public Expression negate()

Create an expression that returns the negation of this expression

Returns: the negated expression

Throws: IllegalOperationException if isNegatable() returns false