Feat: Seperate File for Database Connection

helpmehelpapplication/src/main/java/ntnu/sytemutvikling/team6/database/DatabaseConnection.java

@@ -0,0 +1,96 @@
+package ntnu.sytemutvikling.team6.database;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+
+/**
+ * Represents a reusable database connection through enviroment variables.
+ */
+
+public class DatabaseConnection {
+    private final String databaseURL;
+    private final String username;
+    private final String password;
+    /**
+     * Constructs a new {@code DatabaseConnection} using database credentials
+     * retrieved from system environment variables.
+     * <p>
+     * Required environment variables:
+     * <ul>
+     *     <li>{@code HMH_DB_URL}</li>
+     *     <li>{@code HMH_DB_USERNAME}</li>
+     *     <li>{@code HMH_DB_PASSWORD}</li>
+     * </ul>
+     * </p>
+     *
+     * @throws IllegalStateException if either databaseURL, username, or password is {@code null} or blank
+     */
+
+    // Values stored in system environment variables for security (using ntnu's phpmyadmin for this project)
+    public DatabaseConnection() {
+        this.databaseURL = System.getenv("HMH_DB_URL");
+        this.username = System.getenv("HMH_DB_USERNAME");
+        this.password = System.getenv("HMH_DB_PASSWORD");
+
+        if (this.databaseURL == null || this.databaseURL.isBlank()) {
+            throw new IllegalStateException("Database environment variable URL has not been set");
+        }
+
+        if (this.username == null || this.username.isBlank()) {
+            throw new IllegalStateException("Username environment variable has not been set");
+        }
+
+        if (this.password == null || this.password.isBlank()) {
+            throw new IllegalStateException("Password environment variable has not been set");
+        }
+    }
+
+    /**
+     * Constructs a new {@code DatabaseConnection} using database credentials
+     * <p>
+     *     Used primarily for JUnit tests. Production should use the constructor
+     *     using environment variables.
+     * </p>
+     *
+     * @param databaseURL the url to the database
+     * @param username the username used to log in to the database
+     * @param password the password used to log in to the database
+     * @throws IllegalArgumentException if databaseURL, username, or password is
+     *                                  {@code null} or blank
+     */
+
+    public DatabaseConnection(String databaseURL, String username, String password) {
+        this.databaseURL = databaseURL;
+        this.username = username;
+        this.password = password;
+
+        if (this.databaseURL == null || this.databaseURL.isBlank()) {
+            throw new IllegalArgumentException("Database environment variable URL has not been set");
+        }
+
+        if (this.username == null || this.username.isBlank()) {
+            throw new IllegalArgumentException("Username environment variable has not been set");
+        }
+
+        if (this.password == null || this.password.isBlank()) {
+            throw new IllegalArgumentException("Password environment variable has not been set");
+        }
+    }
+
+
+    /**
+     * Creates and returns a new MySQL database connection.
+     *
+     * @return a {@link Connection} to the database
+     * @throws SQLException if the connection cannot be established
+     */
+    public Connection getMySqlConnection() throws SQLException {
+        return DriverManager.getConnection(databaseURL, username, password);
+    }
+
+    /**
+     *
+     */
+
+}