com.metamatrix.query.sql.lang
Class IsNullCriteria

java.lang.Object
  com.metamatrix.query.sql.lang.Criteria
      com.metamatrix.query.sql.lang.PredicateCriteria
          com.metamatrix.query.sql.lang.IsNullCriteria

All Implemented Interfaces:

LanguageObject, java.io.Serializable, java.lang.Cloneable

public class IsNullCriteria
extends PredicateCriteria

Represents criteria such as: " IS NULL".

See Also:

Serialized Form

Constructor Summary

IsNullCriteria()
Constructs a default instance of this class.

IsNullCriteria(Expression expression)
Constructs an instance of this class with an expression

Method Summary

void	acceptVisitor(LanguageVisitor visitor) Method for accepting a visitor.
java.lang.Object	clone() Deep copy of object
boolean	equals(java.lang.Object obj) Comparees this criteria to another object for equality
Expression	getExpression() Get expression.
int	hashCode() Get hash code.
boolean	isNegated() Returns whether this criteria is negated.
void	setExpression(Expression expression) Set expression.
void	setNegated(boolean negationFlag) Sets the negation flag for this criteria.

Methods inherited from class com.metamatrix.query.sql.lang.Criteria

combineCriteria, combineCriteria, combineCriteria, separateCriteriaByAnd, toConjunctiveNormalForm, toDisjunctiveNormalForm, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

IsNullCriteria

public IsNullCriteria()

Constructs a default instance of this class.

IsNullCriteria

public IsNullCriteria(Expression expression)

Constructs an instance of this class with an expression

Parameters:

expression - The expression to be compared to null

Method Detail

setExpression

public void setExpression(Expression expression)

Set expression.

Parameters:

expression - Expression to compare to null

getExpression

public Expression getExpression()

Get expression.

Returns:

Expression to compare

isNegated

public boolean isNegated()

Returns whether this criteria is negated.

Returns:

flag indicating whether this criteria contains a NOT

setNegated

public void setNegated(boolean negationFlag)

Sets the negation flag for this criteria.

Parameters:

negationFlag - true if this criteria contains a NOT; false otherwise

acceptVisitor

public void acceptVisitor(LanguageVisitor visitor)

Description copied from interface: LanguageObject

Method for accepting a visitor. It is the responsibility of the language object to call back on the visitor.

Parameters:

visitor - Visitor being used

hashCode

public int hashCode()

Get hash code. WARNING: The hash code is based on data in the criteria. If data values are changed, the hash code will change - don't hash this object and change values.

Overrides:

hashCode in class java.lang.Object

Returns:

Hash code for object

equals

public boolean equals(java.lang.Object obj)

Comparees this criteria to another object for equality

Overrides:

equals in class java.lang.Object

Parameters:

obj - Other object

Returns:

True if objects are equal

clone

public java.lang.Object clone()

Deep copy of object

Specified by:

clone in interface LanguageObject

Specified by:

clone in class PredicateCriteria

Returns:

Deep copy of object