org.josql.expressions
Class IsNullExpression

java.lang.Object
  org.josql.expressions.Expression
      org.josql.expressions.BinaryExpression
          org.josql.expressions.IsNullExpression

public class IsNullExpression
extends BinaryExpression

Represents an "IS NULL" (or "IS NOT NULL") expression.

Field Summary

Fields inherited from class org.josql.expressions.BinaryExpression

left, right

Constructor Summary

IsNullExpression()

Method Summary

boolean	isNot()
boolean	isTrue(Object o, Query q) Determine whether the LHS of this expression is or is not null.
void	setNot(boolean v)
String	toString() Return a string representation of this expression.

Methods inherited from class org.josql.expressions.BinaryExpression

getExpectedReturnType, getLeft, getRight, getValue, hasFixedResult, init, setLeft, setRight

Methods inherited from class org.josql.expressions.Expression

isBracketed, setBracketed

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

IsNullExpression

public IsNullExpression()

Method Detail

isNot

public boolean isNot()

setNot

public void setNot(boolean v)

toString

public String toString()

Return a string representation of this expression. In the form: Expression.toString() IS [ NOT ] NULL

Specified by:

toString in class Expression

Returns:

A string representation of this expression.

isTrue

public boolean isTrue(Object o,
                      Query q)
               throws QueryExecutionException

Determine whether the LHS of this expression is or is not null. Note that this is equivalent to: LHS = null or: LHS != null.

Specified by:

isTrue in class Expression

Parameters:

o - The current object to perform the expression on.

q - The Query object.

Returns:

true if the LHS is null (or not null is specified).

Throws:

QueryExecutionException - If the expression cannot be evaluated.