package net.toodarkpark.util.comparison;

import java.util.*;
import org.apache.commons.collections.Predicate;

/*
 * NotPredicate is a implementation of Predicate that contains a single Predicate object, reversing its
 * return value.  useful for eg "q = new NotPredicate( new InPredicate( listOfBadValues ) );"
 * which corresponds to SQL's "NOT IN (list)".
 */

public class NotPredicate implements Predicate
{
    protected Predicate qualifier;
    
    private NotPredicate()
    {
        super();
        qualifier = null;
    }
    
    public NotPredicate( Predicate aPredicate )
    {
        this();
        qualifier = aPredicate;
    }
    
    public boolean evaluate( Object obj )
    {
        // negate whatever's returned 
        return !qualifier.evaluate( obj );
    }
}