Server_Design

Server Side Classes - Database Interaction

Includes class design: Designs of the (public) Java classes that will comprise your programs:

• Descriptions of all public methods and fields.
• Descriptions of the arguments each method takes and what the method returns.
• Any assumptions (preconditions and postconditions).
• Any checked exceptions that may be thrown by the method, and the circumstances under which the exceptions will be thrown.
• How these classes interact with each other (UML Diagram).

These classes are used to interact with a database. Structure inspired by Week 7 Tutorial.

There are 4 categories of classes:

• DBConnection: Connects the server to a database schema.
• DataSource: Executes prepared SQL statement to interact with database.
• Data: Uses a DataSource and its methods to retrieve data.
• DataType: Stores detailed information of certain objects.

DBConnection Class

Connects the server to a database schema.

DBConnection
-instance: Connection
-DBConnection() +getInstance(): Connection

private DBConnection()

• Reads from a config file to retrieve database information (url, username, password, schema).
• Uses DriverManager to connect to database & override instance.

getInstance()

• If there is no current instance, creates one.
• Returns instance.

Data Source Classes

Executes prepared SQL statement to interact with database.

Base Class:

DataSource
+CREATE_TABLE: String -connection: Connection #INSERT: String #GET: String #DELETE: String #add: PreparedStatement #get: PreparedStatement #delete: PreparedStatement
-DataSource() +add(DataType data) +get(Object key) +delete(Object key) +close()

DataSource()

• Connects to database.

close()

• Close connection to database.

Each of the following classes extends the DataSource class and should have at least 3 methods:

• add(DataType data): Add a new row into the database
• get(Object key): Retrieve the row associated to the key
• delete(Object key): Delete the row associated to the key

The classes below inherits DataSource and can modify the SQL Strings (INSERT, GET, DELETE) to adapt to each table.

UsersDataSource

UsersDataSource

OrganisationsDataSource

OrganisationsDataSource

AssetsDataSource

AssetsDataSource

OrdersDataSource

OrdersDataSource

Data Classes

Uses a DataSource and its methods to retrieve data.

Data Type Classes

Stores detailed information of certain objects. These classes will also be used by the client, see Common_Classes Design.