Java Reference
In-Depth Information
as
DOM
objects. In listing 14.10, we use the provided
HTML
DOM
to verify that the
returned web page contains the expected
HTML
table.
In this section we described how to test the frontend of the Administrator applica-
tion. What we're still missing is a few pages that will reveal to us how to unit test the
AdministratorBean
EJB
, which executes our queries on the database. The secrets of
EJB
testing are covered in the next section.
14.5
Testing EJBs
Te s t i n g
EJB
s has a reputation of being a difficult task. One of the main reasons is that
EJB
s are components that run inside a container. You need to either abstract out the
container services used by your code or perform in-container unit testing. In this sec-
tion, we demonstrate different techniques that can help you write
EJB
unit tests. We
also continue developing our Administrator application, showing you the module that
executes the
SQL
queries.
The architecture of the Administrator application goes like this: The command to
be executed gets through the filter, which determines whether it's a
SELECT
query.
After that, the
AdminServlet
eventually receives the command/query.
The execution flow starts in the
AdminServlet
doGet
method. It receives the
HTTP
requests and calls the
getCommand
method to extract the
SQL
query from it. It then
calls
executeCommand
to execute the database call (using the extracted
SQL
query)
and return the results as a
Collection
. The results are then put in the
HTTP
request
(as a request attribute) and, at last,
doGet
calls
callView
to invoke the
JSP
page that
presents the results to the user. So far, we've given no implementation of the
execute-
Command
method. The idea behind it would be to call a given
EJB
, which would execute
the query on a given database. One simple implementation of the
executeCommand
method would be as follows:
public Collection executeCommand(String command) throws Exception {
Context context = new InitialContext();
IAdministratorLocal administrator = (IAdministratorLocal)
context.lookup(“AdministratorBean”);
return administrator.execute(command);
}
The
EJB
itself is shown in listing 14.11.
Listing 14.11
AdministratorEJB
[...]
@Stateless
public class
AdministratorBean
implements
IAdministratorLocal {
public
Collection execute(String sql)
throws
Exception {
Connection connection = getConnection();
// For simplicity, we'll assume the SQL is a SELECT query
ResultSet resultSet =
connection.createStatement().executeQuery(sql);
RowSetDynaClass rsdc = new RowSetDynaClass(resultSet);
B
C
