/*
 * ECatalog is a database front-end, with two main features:
 * 1. Use of preferences
 *  A preference-based approach, where the user is allowed to define the importance of each criterion.
 *  Then the items are ranked accordingly to his criteria.
 * 2. Trade-off analysis
 *  A cooperative database approach, where the system "argues" with the user about his criteria.
 *  When there are no matching items, the system explains the minimal conflicting set and
 *  give some possible strong and weak relaxations about his criteria.
 * This package also containts the software and the set-up details used for our User Study,
 * comparing the use or not of the two previous features mentioned above.
 *
 * Copyright (C) 2006 David Portabella Clotet, Artificial Intelligence Laboratory, EPFL
 * 
 * This file is part of ecatalog-1.0.zip
 * 
 * ECatalog is free software and a free user study set-up;
 * you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * ECatalog is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with ECatalog; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * @version 1.0
 * @author David Portabella
 * To contact the author:
 * email: david@portabella.name and david.portabella@epfl.ch
 * 
 * More information about ECatalog:
 *  http://sourceforge.net/projects/ecatalog/
 *  http://icwww.epfl.ch/~portabel/ecatalogs/
 */

package ecatalog.db;

import ecatalog.ECatalog;
import dpc.utils.SqlUtil;
import java.util.*;
import java.sql.*;
import ecatalog.jaxb.ecatalogConfig.AttributeType;

public class BooleanAttribute extends Attribute {
    final public static int noIndex = 0, yesIndex = 1;
    

    /* The id of all the distinct possible values */
    private boolean[] valuesId;

    /* The index in the array valuesId and valuesString for a given value id */
    private HashMap<Boolean, Integer> valuesIndex;

    public BooleanAttribute(AttributeType config, Database db, int attributeIndex) {
	super(config, db, attributeIndex);
    }

    /* Computes valuesIndex, valuesId, nbrDistinctValues, and valuesString */
    public void init() throws SQLException, Exception {
	getValues();
	computeValuesString();
    }

    /* Computes valuesIndex, valuesId and nbrDistinctValues */
    private void getValues() throws SQLException {
	if (SqlUtil.getUniqueInt(db.executeQuery("SELECT COUNT(*) FROM " + db.fromClause + " WHERE " + db.whereClause + " AND (" + id + " IS NULL OR (" + id + "!= 0 AND " + id + "!= 1))")) > 0) {
	    ECatalog.error(new Error("there not booleans values"));
	    throw new Error(); //it is already done, but to avoid the java compiling error
	}
	valuesId = new boolean[] { false, true };
	valuesIndex = new HashMap<Boolean, Integer>();
	valuesIndex.put(false, 0);
	valuesIndex.put(true, 1);

	nbrDistinctValues = 2;
    }

    /* Computes valuesString */
    private void computeValuesString() throws Exception {
	valuesString = new String[] {"no", "yes"};
    }

    public boolean getValueId(int valueIndex) {
	return valuesId[valueIndex];
    }

    public int getValueIndex(boolean valueId) throws SQLException {
	return valuesIndex.get(valueId);
    }

    public int getValueIndex(ResultSet rs) throws SQLException {
	return getValueIndex(rs, dbColumnIndex);
    }

    public int getValueIndex(ResultSet rs, int dbColumnIndex) throws SQLException {
	return valuesIndex.get(rs.getBoolean(dbColumnIndex));
    }

    public String getDbValueString(int valueIndex, boolean quoteIfNecessary) {
	return String.valueOf(valueIndex);  //0=false, 1=true
    }

    /* For a given valueIndex, it gets a string corresponding to the equal constraint on this value */
    public String getEqualConstraintString(int valueIndex) {
	EqualConstraint c = new EqualConstraint(this, db, new Weight(-1), null);
	c.setValueIndex(valueIndex);
	return c.getWithConstraintString();
    }
}