Task 4 - Implementing service components using JDBC

Step 1

To add Maven into existing project, right-click the project name in the panel Project, and from the context menu select Add Framework Support (Fig. 1).

From the list of frameworks select Maven (Fig. 2). Usually, it is at the bottom of the list.

After that a new file pom.xml will be added into your project. It is a Maven configuration file which allows defining dependencies (libraries, additional modules, etc.) and settings for project building and deployment.

In the pom.xml file, fill in the entries groupId, artifactId and version as follows:

<groupId>sk.tuke</groupId>
<artifactId>gamestudio</artifactId>
<version>0.0.1-SNAPSHOT</version>

Use pom.xml to add a definition of the library into project dependencies. Inside the project element, add the dependencies element with a dependency definition for postgresql, as shown below:

<project ...>
    ...
    <groupId>sk.tuke</groupId>
    <artifactId>gamestudio</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    
    <dependencies>
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>
    </dependencies>
</project>

After that, open the Maven panel (a button to show this panel is usually located on the right edge of the window) and press the button for reloading the project (Fig. 3). Maven will download the library from the internet and set it up in the project.

Comment

For connecting to, creating and managing a database you can use directly IntelliJ IDEA development environment and its tool panel Database (Fig. 4). A button to show this panel is usually located on the right edge of the window. For advanced managing of several databases outside IntelliJ IDEA there is an application available by JetBrains called DataGrip. You can also use application pgAdmin.

Step 2

Add interfaces and entities specifying the service components from the zip archive serviceSpecs.zip into your project. Read the specification description thoroughly. Individual interfaces contain the signatures of required methods that need to be supported by services.

As an example, the implementation of class Score is available.

Step 3

The development environment IntelliJ IDEA has a support for various database systems, so you can create tables for service data directly in the development environment. There is a graphical editor available for working with tables (dialogue windows), but also an option to write and execute your own database script.

You can create new table in the IntelliJ IDEA environment through tool panel Database (a button to show this panel is usually located on the right edge of the window). By clicking and expanding the name of connected database you will get to the schema (entry schemas->public). A right-click on the schema will show a context menu, from which you can choose option New->Table (see the image below).

After that a dialogue window will appear, in which you can add database columns by using buttons, and set their data types (the upper part of the window). Alternatively, you can use the text field to enter the command for creation of the table (the lower part of the window). When adding columns by the button +, the command in the text field will be also automatically generated, matching the columns in created database.

Step 4

To implement the services you will need:

• Database connection credentials (URL, login, password),
• SQL commands that will be used in the particular service component methods,
• Implementation of the interfaces' methods along with connection to the database, exception handling and closing the database connection.

Step 5

For example, service score should be integrated into the game by storing player's score automatically after finishing the game (or a level). After that, either automatically or by user-initiated action (command), a list of top 10 players and their scores should be printed.

Similarly, integrate services comment and rating into your game.

Step 6