package pt.iscte.ci.aop.pooling;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 
 * This code has been adapted from the book AspectJ in Action.
 * 
 * TODO: This class must be more than this, namely to consider factors such as
 * the size of the pool.
 * 
 * @author Paulo Zenida
 * 
 */
public class FenixDBConnectionPool implements DBConnectionPool {

    private List<Connection> pooledConnections = new ArrayList<Connection>();

    private Map<DBConnectionDescription, List<Connection>> connectionsDescriptionMap = new HashMap<DBConnectionDescription, List<Connection>>();

    synchronized public Connection getConnection(String url, String username, String password)
	    throws SQLException {
	final DBConnectionDescription desc = new DBConnectionDescription(url, username, password);
	final List<Connection> connectionsList = getConnections(desc);
	if (connectionsList == null) {
	    return null;
	}
	for (int size = pooledConnections.size(), i = 0; i < size; ++i) {
	    final Connection connection = pooledConnections.get(i);
	    if (connectionsList.contains(connection)) {
		pooledConnections.remove(connection);
		if (!connection.isClosed()) {
		    return connection;
		}
	    }
	}
	return null;
    }

    synchronized public boolean putConnection(final Connection connection) {
	pooledConnections.add(connection);
	return true;
    }

    synchronized public void registerConnection(Connection connection, String url, String username,
	    String password) {
	final DBConnectionDescription desc = new DBConnectionDescription(url, username, password);
	List<Connection> connectionsList = getConnections(desc);
	if (connectionsList == null) {
	    connectionsList = new ArrayList<Connection>();
	    connectionsDescriptionMap.put(desc, connectionsList);
	}
	connectionsList.add(connection);
    }

    private List<Connection> getConnections(DBConnectionDescription desc) {
	return connectionsDescriptionMap.get(desc);
    }
}