MySQLExcpetionDAO.java

/* SAAF: A static analyzer for APK files.
 * Copyright (C) 2013  syssec.rub.de
 *
 * 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/>.
 */
package de.rub.syssec.saaf.db.dao.mysql;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;
import java.util.List;

import de.rub.syssec.saaf.db.dao.exceptions.DAOException;
import de.rub.syssec.saaf.db.dao.exceptions.DuplicateEntityException;
import de.rub.syssec.saaf.db.dao.exceptions.NoSuchEntityException;
import de.rub.syssec.saaf.db.dao.interfaces.NuExceptionDAO;
import de.rub.syssec.saaf.model.SAAFException;

/**
 * @author Tilman Bender <tilman.bender@rub.de>
 *
 */
public class MySQLExcpetionDAO implements NuExceptionDAO {

	private static final String DB_COLUMN_ANALYSIS = "id_analyses";
	private static final String DB_COLUMN_MESSAGE = "error_message";	
	private static final String DB_COLUMN_ID = "id";
	private static final String DB_QUERY_CREATE = "INSERT INTO error_messages("+DB_COLUMN_ANALYSIS+","
																				+DB_COLUMN_MESSAGE+")VALUES(?,?)";
	private static final String DB_QUERY_UPDATE = "UPDATE error_messages SET "+DB_COLUMN_ANALYSIS+"=?,"
																			  +DB_COLUMN_MESSAGE+"=? WHERE "
																			  +DB_COLUMN_ID+"=?";
	private static final String DB_QUERY_DELETE = "DELETE FROM error_messages WHERE "+DB_COLUMN_ID+"=?";
	private static final String DB_QUERY_DELETE_ALL = "DELETE FROM error_messages";

	private Connection connection;

	/**
	 * Creates a MySQLExcpetionDAO that uses the supplied Connection.
	 * @param connection
	 */
		public MySQLExcpetionDAO(Connection connection) {
			super();
			this.connection = connection;
		}
	
	/* (non-Javadoc)
	 * @see de.rub.syssec.saaf.db.dao.GenericDAO#create(java.lang.Object)
	 */
	@Override
	public int create(SAAFException entity) throws DAOException, DuplicateEntityException {
		PreparedStatement statement;
		int id;
		int index=0;
		try {
			statement = connection.prepareStatement(DB_QUERY_CREATE, Statement.RETURN_GENERATED_KEYS);
			if(entity.getAnalysis()!=null)
			{
				statement.setInt(++index, entity.getAnalysis().getId());
			}else
			{
				statement.setNull(++index, Types.INTEGER);
			}
			
			if(entity.getMessage()!=null)
			{
				statement.setString(++index, entity.getMessage());
			}else
			{
				statement.setNull(++index, Types.VARCHAR);
			}
		
			statement.executeUpdate();
			ResultSet rs = statement.getGeneratedKeys();
			if (rs.next()) {
				id = rs.getInt(1);
			} else {
				throw new DAOException(
						"Autogenerated keys coudl not be retrieved!");
			}
		} catch (SQLException e) {
			//use the SQL Error Code to throw specific exception for duplicate entries
			if(e.getSQLState().equalsIgnoreCase(SQL_ERROR_DUPLICATE) && e.getMessage().toLowerCase().contains("duplicate"))
			{
				throw new DuplicateEntityException("An entity with the same key attributes already exists",e);
			}else
			{
				throw new DAOException(e);
			}
		}	
		//otherwise continue persisting the primitive types and 1-1 associations
		return id;
	}

	/* (non-Javadoc)
	 * @see de.rub.syssec.saaf.db.dao.GenericDAO#read(int)
	 */
	@Override
	public SAAFException read(int id) throws DAOException {
		throw new UnsupportedOperationException("Reading exceptions is not implemented yet");
	}

	/* (non-Javadoc)
	 * @see de.rub.syssec.saaf.db.dao.GenericDAO#update(java.lang.Object)
	 */
	@Override
	public boolean update(SAAFException entity) throws DAOException, NoSuchEntityException {
		boolean success = false;
		int recordsUpdated;
		PreparedStatement updateStmt;

		try {
			updateStmt = connection.prepareStatement(DB_QUERY_UPDATE);
			if(entity.getAnalysis()!=null)
			{
				updateStmt.setInt(1, entity.getAnalysis().getId());
			}else
			{
				updateStmt.setNull(1, Types.INTEGER);
			}
			
			if(entity.getMessage()!=null)
			{
				updateStmt.setString(2, entity.getMessage());
			}else
			{
				updateStmt.setNull(2, Types.VARCHAR);
			}
			updateStmt.setInt(3, entity.getId());
			recordsUpdated = updateStmt.executeUpdate();
			// this should affect at most one record
			if (recordsUpdated == 0){
				throw new NoSuchEntityException();
			}else if(recordsUpdated == 1) {
				success = true;
			} else {
				// the update affected multiple records this should not happen!
				throw new DAOException("Update of one entity affected multiple records. This should not happen!");
			}
		} catch (SQLException e) {
			throw new DAOException(e);
		}
		return success;
	}

	/* (non-Javadoc)
	 * @see de.rub.syssec.saaf.db.dao.GenericDAO#delete(java.lang.Object)
	 */
	@Override
	public boolean delete(SAAFException entity) throws DAOException, NoSuchEntityException {
		boolean success = false;
		int recordsAffected;
		try {
			PreparedStatement deleteStmt = connection
					.prepareStatement(DB_QUERY_DELETE);
			deleteStmt.setInt(1, entity.getId());
			recordsAffected = deleteStmt.executeUpdate();
			// this should affect at most one record
			if(recordsAffected==0){
				throw new NoSuchEntityException();
			}else if (recordsAffected == 1) {
				success = true;
			} else if(recordsAffected >1) {
				throw new DAOException("Delete of one entity affected multiple records. This should not happen!");
			}

		} catch (SQLException e) {
			throw new DAOException(e);
		}
		return success;
	}

	@Override
	public List<SAAFException> readAll() {
		throw new UnsupportedOperationException("Reading exceptions is not implemented yet");
	}

	@Override
	public int deleteAll() throws DAOException {
		int recordsAffected;
		try {
			PreparedStatement deleteStmt = connection.prepareStatement(DB_QUERY_DELETE_ALL);
			recordsAffected = deleteStmt.executeUpdate();
		} catch (SQLException e) {
			throw new DAOException(e);
		}
		return recordsAffected;
	}

	@Override
	public int findId(SAAFException candidate) throws DAOException {
		throw new UnsupportedOperationException("Not implemented");
	}

}