public List<Computer> getListComputer(Wrapper computerWrapper) throws SQLException, ClassNotFoundException {
		Connection cn=DaoFactory.getInstance().getConnection();

		ArrayList<Computer> listComputer  = new ArrayList<Computer>();
		ResultSet rs = null ;
		PreparedStatement stmt = null;
		if(computerWrapper.getFilterby()=="" || computerWrapper.getFilterby() == null){
			computerWrapper.setFilterby("computer");
		}
		if(computerWrapper.getOrder()=="" || computerWrapper.getOrder() == null){
			computerWrapper.setOrder("computer.id");
		}
		StringBuilder sb=new StringBuilder();

		if (computerWrapper.getFilter()!="" && computerWrapper.getFilter()!=null){
			sb.append("SELECT computer.id,computer.name,computer.introduced,computer.discontinued,computer.company_id,company.name FROM computer LEFT OUTER JOIN company ON computer.company_id=company.id WHERE(").append(computerWrapper.getFilterby()).append(".name LIKE '%").append(computerWrapper.getFilter()).append("%') ORDER BY ").append(computerWrapper.getOrder())
			.append(" LIMIT ").append(computerWrapper.getOffset())
			.append(",").append(computerWrapper.getNumberPerPage());

		}
		else{
			sb.append("SELECT computer.id,computer.name,computer.introduced,computer.discontinued,computer.company_id,company.name FROM computer LEFT OUTER JOIN company ON computer.company_id=company.id ORDER BY ")
			.append(computerWrapper.getOrder())
			.append(" LIMIT ")
			.append(computerWrapper.getOffset())
			.append(",")
			.append(computerWrapper.getNumberPerPage());

		}
		stmt=cn.prepareStatement(sb.toString());
		rs = stmt.executeQuery();

		while (rs.next()) {

			Company company=Company.builder()
					.id(rs.getLong(5))
					.name(rs.getString(6))
					.build();

			Computer p = Computer.builder()
					.id(rs.getLong(1))
					.name(rs.getString(2))

					.introduced(rs.getDate(3))
					.discontinued(rs.getDate(4))
					.company(company)
					.build();

			listComputer.add(p);	

		}

		if (rs != null){

			rs.close();
		}

		if (stmt != null){

			stmt.close();
		}

		return listComputer;
	}