com.metamatrix.query.sql.lang
Class CompareCriteria

java.lang.Object
  com.metamatrix.query.sql.lang.Criteria
      com.metamatrix.query.sql.lang.PredicateCriteria
          com.metamatrix.query.sql.lang.AbstractCompareCriteria
              com.metamatrix.query.sql.lang.CompareCriteria

All Implemented Interfaces:

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

public class CompareCriteria
extends AbstractCompareCriteria
implements PredicateCriteria.Negatable

A criteria which represents a simple operator relationship between two expressions. There are 6 operator types. Each side of the comparison may be an expression, which could be an element, a constant, or a function.

Some examples are:

• ticker = 'IBM'
• price >= 50
• revenue < 0
• 5 <= length(companyName)

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.metamatrix.query.sql.lang.PredicateCriteria

PredicateCriteria.Negatable

Field Summary

Fields inherited from class com.metamatrix.query.sql.lang.AbstractCompareCriteria

EQ, GE, GT, LE, LT, NE

Constructor Summary

CompareCriteria()
Constructs a default instance of this class.

CompareCriteria(Expression leftExpression, int operator, Expression rightExpression)
Constructs an instance of this class for a specific "operand operator operand" clause.

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) Override equals() method.
static int	getInverseOperator(int op)
Expression	getRightExpression() Get right expression.
int	hashCode() Get hash code.
boolean	isOptional() Returns true if the compare criteria is used as join criteria, but not needed during processing.
void	negate()
void	set(Expression leftExpression, int operator, Expression rightExpression) Sets the operands and operator.
void	setOptional(boolean isOptional) Set during planning to indicate that this criteria is no longer needed to correctly process a join
void	setRightExpression(Expression expression) Set right expression.

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

getLeftExpression, getOperator, getOperator, getOperatorAsString, setLeftExpression, setOperator

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

CompareCriteria

public CompareCriteria()

Constructs a default instance of this class.

CompareCriteria

public CompareCriteria(Expression leftExpression,
                       int operator,
                       Expression rightExpression)

Constructs an instance of this class for a specific "operand operator operand" clause.

Parameters:

identifier - The variable being compared

value - The value the variable is being compared to (literal or variable)

operator - The operator representing how the variable and value are to be compared

Method Detail

setRightExpression

public void setRightExpression(Expression expression)

Set right expression.

Parameters:

expression - Right expression

getRightExpression

public Expression getRightExpression()

Get right expression.

Specified by:

getRightExpression in class AbstractCompareCriteria

Returns:

right expression

set

public void set(Expression leftExpression,
                int operator,
                Expression rightExpression)

Sets the operands and operator. The clause is of the form: .

Parameters:

leftExpression - The left expression

operator - The operator representing how the expressions are compared

rightExpression - The right expression

setOptional

public void setOptional(boolean isOptional)

Set during planning to indicate that this criteria is no longer needed to correctly process a join

Parameters:

isOptional -

isOptional

public boolean isOptional()

Returns true if the compare criteria is used as join criteria, but not needed during processing.

Returns:

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.

Specified by:

acceptVisitor in interface LanguageObject

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

equals

public boolean equals(java.lang.Object obj)

Override equals() method.

Overrides:

equals in class java.lang.Object

Parameters:

obj - Other object

Returns:

true if objects are equivalent

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

negate

public void negate()

Specified by:

negate in interface PredicateCriteria.Negatable

getInverseOperator

public static int getInverseOperator(int op)