This is a standard format JavaFBP component, with the usual sections:
- imports
- port attributes
- 'execute' method
- 'openPorts' method
Let us take a look at the 'execute' method - please bring it up in a separate window.
// Step 1: Allocate a database 'Connection' object
Connection conn = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/ebookshop?allowPublicKeyRetrieval=true&useSSL=false&serverTimezone=UTC",
"root", pswd);
// The format is: "jdbc:mysql://hostname:port/databaseName", "username", "password"
As you can see (see the diagram above), the password has already been externalized by putting it in a file, and reading the contents into a separate (JavaFBP) input port.
Note that FBP uses the term "port", but the client and server also use the term "port", which in this case has a standard value of 3306. In what follows, "port" will be taken to refer to FBP "ports", unless otherwise specified.
In the Connection statement above, we suggest that all the parts be obtained from different input ports, with database name and user name perhaps being in IIPs. Of course, FBP allows them to be obtained from any source. The diagram now becomes the following:
Note that the password is coming in from a file, while the other two parameters are in IIPs - as far as the network is concerned. Of course ReadJDBC doesn't care - the designer is free to obtain these three parameters from any source s/he likes... We (the network designer) decided to put the password in a separate file simply to provide better security... We could for instance insert an encryption component between the ReadFile process and ReadJDBC.
We now have to update ReadJDBC.java to receive from the additional input ports. Since ReadJDBC.java will be going through a number of iterations, we will put successive versions in the appropriate code directory for a given Stepxx directory.
Updating ReadJDBC.java, up to this point, is very straightforward, as we just have to add two annotations, two openInput calls, and the logic to receive the additional inputs. One glitch: if you have more than one @InPort annotation, they have to be surrounded with an @InPorts annotation. See https://github.com/jpaulm/fbp-etl/blob/master/src/main/java/com/jpaulmorrison/Step08/code/components/ReadJDBC.java .
The output of the run is of course exactly the same as in Step05.
This is a minor change: JavaFBP ShowText uses the JavaSwing JFrame class, so the output appears in a separate window. ShowText also requires a title, specified in an IIP attached to its TITLE port. The revised diagram is now as follows:
This diagram was used to generate a network, which was then run - with the selected rows appearing in a separate window.
If you take a closer look, you will notice that the two lines "The SQL statement is..." and "Total number of records..." are separated from the output of the MySQL select statement, so that the former appear on the debugging console.
Combining these outputs into one image, this will look roughly as follows (I have put a border around this extracted diagram for reading ease):
