SiLeBAT/FSK-Lab

/*******************************************************************************
 * Copyright (c) 2015 Federal Institute for Risk Assessment (BfR), Germany
 *
 * This program is free software: 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Contributors:
 *     Department Biological Safety - BfR
 *******************************************************************************/
package de.bund.bfr.knime.pmm.common.generictablemodel;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Enumeration;
import java.util.HashMap;

import de.bund.bfr.knime.pmm.common.PmmException;

public class DbRelationReader implements Enumeration<KnimeTuple> {
    
    private String query;
    private HashMap<String,String> mapKnimeDb;
    private Connection conn;
    private PreparedStatement stat;
    private ResultSet result;
    private KnimeSchema schema;
    private boolean hasMore;
    
    public DbRelationReader( KnimeSchema schema ) throws PmmException {
        
        if( schema == null )
            throw new PmmException( "Schema must not be null." );
        
        this.schema = schema;
        mapKnimeDb = new HashMap<>();
        hasMore = false;
    }
    
    public void addSibling( String knime, String db ) throws PmmException {
        
        if( !schema.containsAtt( knime ) )
            throw new PmmException( "The attribute '"+knime+"' does not exist in schema." );
        
        mapKnimeDb.put( knime, db );
    }
    
    @Override
    public boolean hasMoreElements() {
        return hasMore;
    }
    
    public void init() throws SQLException, PmmException {
        
        // String att;
        
        if( result != null )
            result.close();
        
        /* att = missingAttribute();
        
        if( att != null )
            throw new PmmException( "Mapping incomplete. Attribute '"+att+"' has no sibling." ); */
        
        result = stat.executeQuery();
        hasMore = result.next();
    }
    
    public String missingAttribute() {
        
        int i;
        
        for( i = 0; i < schema.size(); i++ )
            if( !mapKnimeDb.containsKey( schema.getName( i ) ) )
                return schema.getName( i );
        
        return null;
    }

    @Override
    public KnimeTuple nextElement() {
        
        KnimeTuple tuple;
        String value;
        
        tuple = null;
        if( !hasMore )
            return null;
        
        try {
            
            tuple = new KnimeTuple( schema );
            
            for( String knimeAtt : mapKnimeDb.keySet() ) {
                
                value = result.getString( mapKnimeDb.get( knimeAtt ) );
                tuple.setValue( knimeAtt, value );
            }
            
            hasMore = result.next();    
        }
        catch( Exception e ) {
            e.printStackTrace( System.err );
        }

        
        return tuple;
    }
    
    public void setConn( final Connection conn ) throws SQLException {
        
        this.conn = conn;
        
        if( query != null )
            stat = conn.prepareStatement( query );
    }
    
    public void setQuery( final String query ) throws SQLException {
        
        this.query = query;
        
        if( !( conn == null || query == null ) )
            stat = conn.prepareStatement( query );
        else
            stat = null;
    }
    
    public void setStat( final PreparedStatement stat ) throws SQLException {
        
        this.stat = stat;
        query = null;
        
        if( stat == null )
            conn = null;
        else
            conn = stat.getConnection();
    }
    
    public void close() throws SQLException {
        
        result.close();
        stat.close();
        conn.close();
    }
    
}