Heavily refactored DatabaseManager.java and SimpleDatabaseManager.java. Fully refactored DatabaseGoodCasesTest.java and DatabaseBadCasesTest.java.

src/main/java/hhn/temp/project/provider/Database.java

@@ -4,8 +4,26 @@ import java.io.IOException;
 import java.nio.file.Path;
 import java.sql.SQLException;
 
+/**
+ * A database interface with basic database connectivity
+ * @author Riley Schneider
+ */
 public interface Database {
-  public void connect() throws SQLException;
+  /**
-  public void close() throws SQLException;
+   * Creates a connection to the database
-  public void clearDatabase() throws SQLException;
+   * @throws SQLException Thrown if database error occurs
+   */
+  void connect() throws SQLException;
+
+  /**
+   * Closes a connection to the database
+   * @throws SQLException Thrown if database error occurs
+   */
+  void close() throws SQLException;
+
+  /**
+   * Clears the entire tables in the database and reset primary key counter to each table
+   * @throws SQLException Thrown if database error occurs
+   */
+  void clearDatabase() throws SQLException;
 }

src/main/java/hhn/temp/project/provider/DatabaseManager.java

@@ -1,16 +1,115 @@
 package hhn.temp.project.provider;
 
-import jdk.jshell.spi.ExecutionControl;
+import hhn.temp.project.Task;
+import hhn.temp.project.Worker;
 
-import java.io.IOException;
 import java.sql.SQLException;
 import java.util.Collection;
 
-public interface DatabaseManager<E> extends Database {
+/**
-  public void saveObjects(Collection<E> objects) throws SQLException;
+ * Simple Database Manager to handle simple command such as insertion, deletion, updating of Task and Worker objects.
-  public Collection<E> getObjects() throws SQLException;
+ * @author Riley Schneider
-  public void saveObject(E object) throws SQLException;
+ */
-  public E getObject(int taskId) throws SQLException;
+public interface DatabaseManager extends Database {
-  public void deleteObject(int taskId) throws SQLException;
+  /**
-  public E updateObject(int taskId, E object) throws SQLException;
+   * Saves a Task object into the database
+   * @param task Task to be saved into the database
+   * @throws SQLException Thrown if database error occurs
+   */
+  void saveTask(Task task) throws SQLException;
+
+  /**
+   * Saves a collection of Task objects into the database
+   * @param tasks Tasks to be saved into the database
+   * @throws SQLException Thrown if database error occurs
+   */
+  void saveTasks(Collection<Task> tasks) throws SQLException;
+
+  /**
+   * Saves a Worker object into the database
+   * @param worker Worker to be saved into the database
+   * @throws SQLException Thrown if database error occurs
+   */
+  void saveWorker(Worker worker) throws SQLException;
+
+  /**
+   * Saves a collection Worker objects into the database
+   * @param workers Workers to be saved into the database
+   * @throws SQLException Thrown if database error occurs
+   */
+  void saveWorkers(Collection<Worker> workers) throws SQLException;
+
+  /**
+   * Updates a Task object that already exists in the database
+   * @param taskId The ID of the given task
+   * @param newTaskObject The new Task object that will overwrite the existent task on database
+   * @throws SQLException Thrown if database error occurs
+   */
+  void updateTask(int taskId, Task newTaskObject) throws  SQLException;
+
+  /**
+   * Updates a Worker object that already exists in the database
+   * @param workerId The ID of the given worker
+   * @param newWorkerObject The new Worker object that will overwrite the existent task on database
+   * @throws SQLException Thrown if database error occurs
+   */
+  void updateWorker(int workerId, Worker newWorkerObject) throws  SQLException;
+
+  /**
+   * Deletes a task from the database
+   * @param taskId The ID of the given task that needs to be deleted
+   * @throws SQLException Thrown if database error occurs
+   */
+  void deleteTask(int taskId) throws  SQLException;
+
+  /**
+   * Deletes a worker from the database
+   * @param workerId The ID of the given worker that needs to be deleted
+   * @throws SQLException Thrown if database error occurs
+   */
+  void deleteWorker(int workerId) throws  SQLException;
+
+  /**
+   * Gets a collection of all tasks available in the database
+   * @return A collection of tasks (empty if no task available)
+   * @throws SQLException Thrown if database error occurs
+   */
+  Collection<Task> getTasks() throws SQLException;
+
+  /**
+   * Gets a collection of all workers available in the database
+   * @return A collection of workers (empty if no task available)
+   * @throws SQLException Thrown if database error occurs
+   */
+  Collection<Worker> getWorkers() throws SQLException;
+
+  /**
+   * Gets a task given by its ID from the database
+   * @param taskId The task ID
+   * @return A task from the database (NULL if no task found)
+   * @throws SQLException Thrown if database error occurs
+   */
+  Task getTaskByTaskId(int taskId) throws SQLException;
+
+  /**
+   * Gets a worker given by its ID from the database
+   * @param workerId The worker ID
+   * @return A worker from the database (NULL if no worker found)
+   * @throws SQLException Thrown if database error occurs
+   */
+  Worker getWorkerByWorkerId(int workerId) throws SQLException;
+
+  /**
+   * Gets the total number of available tasks in the database.
+   * @return The total number of tasks (0 = zero entries; -1 = error)
+   * @throws SQLException Thrown if database error occurs
+   */
+  int getTotalNumberOfTasks() throws  SQLException;
+
+  /**
+   * Gets the total number of available workers in the database.
+   * @return The total number of workers (0 = zero entries; -1 = error)
+   * @throws SQLException Thrown if database error occurs
+   */
+  int getTotalNumberOfWorkers() throws  SQLException;
 }

src/main/java/hhn/temp/project/provider/SimpleDatabaseManager.java

@@ -1,152 +1,94 @@
 package hhn.temp.project.provider;
 
 import hhn.temp.project.Task;
-import hhn.temp.project.TaskState;
+import hhn.temp.project.Worker;
 
 import java.sql.*;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collection;
-import java.util.List;
 
-public class SimpleDatabaseManager<E> implements DatabaseManager<E> {
+public class SimpleDatabaseManager implements DatabaseManager {
 
-  private Connection connection;
+  @Override
-
+  public void saveTask(Task task) throws SQLException {
-  private enum QueryMode {
+    throw new SQLException();
-    SELECT, INSERT, DELETE, UPDATE
   }
 
-  private int taskStateToInt(TaskState taskState) {
+  @Override
-    return (taskState == TaskState.FINISHED) ? 1 : 0;
+  public void saveTasks(Collection<Task> tasks) throws SQLException {
+    throw new SQLException();
   }
 
-  private TaskState intToTaskState(int i) {
+  @Override
-    if (i < 0 || i > 1) {
+  public void saveWorker(Worker worker) throws SQLException {
-      throw new IllegalArgumentException("Integer may only bet 0 or 1");
+    throw new SQLException();
   }
 
-    return (i == 1) ? TaskState.FINISHED : TaskState.IN_PROGRESS;
+  @Override
+  public void saveWorkers(Collection<Worker> workers) throws SQLException {
+    throw new SQLException();
   }
 
-  private String getQuery(QueryMode query) {
+  @Override
-    String queryString = null;
+  public void updateTask(int taskId, Task newTaskObject) throws SQLException {
-
+    throw new SQLException();
-    switch (query) {
-      case INSERT -> queryString = "INSERT INTO Task (taskid, name, description, workerid, taskstate) VALUES (?, ?, ?, ?, ?)";
-      case UPDATE -> queryString = "UPDATE Task SET name = ?, description = ?, taskstate = ? WHERE taskid = ?";
-      case DELETE -> queryString = "DELETE FROM Task WHERE taskid = ?";
-      case SELECT -> queryString = "SELECT * FROM Task WHERE workerid = ?";
   }
 
-    return queryString;
+  @Override
+  public void updateWorker(int workerId, Worker newWorkerObject) throws SQLException {
+    throw new SQLException();
+  }
+
+  @Override
+  public void deleteTask(int taskId) throws SQLException {
+    throw new SQLException();
+  }
+
+  @Override
+  public void deleteWorker(int workerId) throws SQLException {
+    throw new SQLException();
+  }
+
+  @Override
+  public Collection<Task> getTasks() throws SQLException {
+    throw new SQLException();
+  }
+
+  @Override
+  public Collection<Worker> getWorkers() throws SQLException {
+    throw new SQLException();
+  }
+
+  @Override
+  public Task getTaskByTaskId(int taskId) throws SQLException {
+    return new Task(0, 0, null, null);
+  }
+
+  @Override
+  public Worker getWorkerByWorkerId(int workerId) throws SQLException {
+    return new Worker(null, 0);
+  }
+
+  @Override
+  public int getTotalNumberOfTasks() throws SQLException {
+    return -1;
+  }
+
+  @Override
+  public int getTotalNumberOfWorkers() throws SQLException {
+    return -1;
   }
 
   public void clearDatabase() throws SQLException {
-    try (Statement statement = connection.createStatement()) {
+    throw new SQLException();
-      statement.executeUpdate("TRUNCATE TABLE Task;");
-    }
-  }
-
-  @Override
-  public void saveObjects(Collection<E> objects) throws SQLException {
-    for (E obj : objects) {
-      saveObject(obj);
-    }
-  }
-
-
-  @Override
-  public Collection<E> getObjects() throws SQLException {
-    return null;
-  }
-
-  @Override
-  public void saveObject(E object) throws SQLException {
-    String query = getQuery(QueryMode.INSERT);
-
-    if (object instanceof Task task) {
-      PreparedStatement ps = connection.prepareStatement(query);
-      ps.setInt(1, task.getTaskId());
-      ps.setString(2, task.getName());
-      ps.setString(3, task.getDescription());
-      ps.setInt(4, task.getWorkerId());
-      ps.setInt(5, taskStateToInt(task.getTaskState()));
-
-      ps.executeUpdate();
-    }
-  }
-
-  @Override
-  public E getObject(int taskId) throws SQLException {
-    String query = getQuery(QueryMode.SELECT);
-    Task task = null;
-
-    PreparedStatement ps = connection.prepareStatement(query);
-    ps.setInt(1, taskId);
-
-    ResultSet resultSet = ps.executeQuery();
-
-    if (resultSet.next()) {
-
-      task = new Task(
-              resultSet.getInt("taskid"),
-              resultSet.getInt("workerid"),
-              resultSet.getString("name"),
-              resultSet.getString("description")
-      );
-      task.setTaskState(intToTaskState(resultSet.getInt("taskstate")));
-    }
-
-    return (E) task;
-  }
-
-  @Override
-  public void deleteObject(int taskId) throws SQLException {
-    String query = getQuery(QueryMode.DELETE);
-
-    try (PreparedStatement ps = connection.prepareStatement(query)) {
-      ps.setInt(1, taskId);
-      ps.executeUpdate();
-    }
-  }
-
-  @Override
-  public E updateObject(int taskId, E object) throws SQLException {
-    String query = getQuery(QueryMode.UPDATE);
-
-    if (object instanceof Task task) {
-
-      if (taskId != task.getTaskId()) {
-        throw new IllegalArgumentException("Task ID does not equals Task ID from Task!");
-      }
-
-      PreparedStatement ps = connection.prepareStatement(query);
-      ps.setString(1, task.getName());
-      ps.setString(2, task.getDescription());
-      ps.setInt(3, taskStateToInt(task.getTaskState()));
-      ps.setInt(4, task.getTaskId());
-
-      int updated = ps.executeUpdate();
-
-      if (updated == 0) {
-        return null;
-      }
-
-      return (E) task;
-    }
-
-    return null;
   }
 
   @Override
   public void connect() throws SQLException {
-    connection = DriverManager.getConnection("jdbc:mysql://sql7.freesqldatabase.com/sql7810540?user=sql7810540&password=mXdJCFtDZz");
+    throw new SQLException();
   }
 
   @Override
   public void close() throws SQLException {
-    if (connection != null) {
+    throw new SQLException();
-      connection.close();
-    }
   }
 }

test/hhn/temp/project/DatabaseBadCasesTest.java

@@ -13,36 +13,34 @@ import static org.junit.jupiter.api.Assertions.*;
 
 public class DatabaseBadCasesTest {
 
-  private DatabaseManager<Task> databaseManager;
+  private DatabaseManager databaseManager;
-
-  public class TestClass {
-    private int id;
-    private String dataString;
-    private int dataInteger;
-
-    public TestClass(int id, String dataString, int dataInteger) {
-      this.id = id;
-      this.dataString = dataString;
-      this.dataInteger = dataInteger;
-    }
-  }
 
   @BeforeEach
-  public void setup() throws SQLException, IOException {
+  public void setup() throws SQLException {
-    databaseManager = new SimpleDatabaseManager<>();
+    databaseManager = new SimpleDatabaseManager();
     databaseManager.connect();
     databaseManager.clearDatabase();
   }
 
   @Test
-  @DisplayName("Gets an object that may not be existent")
+  @DisplayName("Inserting Tasks with the same ID")
-  public void assertObjectShouldNotBeExistent() throws SQLException {
+  public void insertTasksWithTheSameId() throws SQLException {
-    assertNull(databaseManager.getObject(999));
+    Task task = new Task(10, 10, "ABC", "XYZ");
+    Task taskFaker = new Task(10, 5, "ABC!", "XYZ!");
+
+    databaseManager.saveTask(task);
+
+    databaseManager.saveTask(taskFaker);
   }
 
   @Test
-  @DisplayName("Updates an object that does not exist")
+  @DisplayName("Inserting Workers with the same ID")
-  public void assertUpdateNonExistentObject() throws SQLException {
+  public void insertWorkersWithTheSameId() throws SQLException {
-    assertNull(databaseManager.updateObject(123, new Task(123, 2, "", "")));
+    Worker worker = new Worker("Worker-1", 1);
+    Worker workerFaker = new Worker("Worker-100", 1);
+
+    databaseManager.saveWorker(worker);
+
+    databaseManager.saveWorker(workerFaker);
   }
 }

test/hhn/temp/project/DatabaseGoodCasesTest.java

@@ -12,103 +12,75 @@ import java.io.IOException;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.List;
 
 public class DatabaseGoodCasesTest {
 
-  private DatabaseManager<Task> databaseManager;
+  private DatabaseManager databaseManager;
 
   @BeforeEach
-  public void setup() throws SQLException, IOException {
+  public void setup() throws SQLException {
-    databaseManager = new SimpleDatabaseManager<>();
+    databaseManager = new SimpleDatabaseManager();
     databaseManager.connect();
     databaseManager.clearDatabase();
   }
 
   @Test
-  @DisplayName("Assert that the TestClass could be inserted into the database")
+  @DisplayName("Inserting test task into the database and receiving back the same test task")
-  public void assertGetTestClass() throws SQLException {
+  public void insertTaskAndReceiveItBackTest() throws SQLException {
+    Task task = new Task(123, 10, "Hello World", "Doing Something, hell yeah!");
 
-    databaseManager.connect();
+    databaseManager.saveTask(task);
 
-    Task task = new Task(1, 1, "hi", "hi");
+    Task reTask = databaseManager.getTaskByTaskId(task.getTaskId());
 
-    databaseManager.saveObject(task);
+    assertNotNull(reTask);
+    assertEquals(task.getTaskId(), reTask.getTaskId());
+    assertEquals(task.getDescription(), reTask.getDescription());
+    assertEquals(task.getName(), reTask.getName());
+    assertEquals(task.getWorkerId(), reTask.getWorkerId());
 
-    Task taskNew = databaseManager.getObject(1);
+    assertEquals(1, databaseManager.getTotalNumberOfTasks());
-
-    assertEquals(task.getTaskId(), taskNew.getTaskId());
-    assertEquals(task.getName(), taskNew.getName());
-    assertEquals(task.getDescription(), taskNew.getDescription());
-    assertEquals(task.getWorkerId(), taskNew.getWorkerId());
-    assertEquals(task.getTaskState(), taskNew.getTaskState());
-
-    databaseManager.close();
   }
 
   @Test
-  @DisplayName("Assert that an inserted and deleted task is not there anymore")
+  @DisplayName("Inserting test worker into the database and receiving back the same test worker")
-  public void assertDeleteTest() throws SQLException {
+  public void insertWorkerAndReceivedItBackTest() throws SQLException {
+    Worker worker = new Worker("Worker-01", 12345678);
 
-    databaseManager.connect();
+    databaseManager.saveWorker(worker);
 
-    Task task = new Task(9, 1, "hi", "hi");
+    Worker reWorker = databaseManager.getWorkerByWorkerId(worker.getId());
 
-    databaseManager.saveObject(task);
+    assertNotNull(reWorker);
 
-    databaseManager.deleteObject(9);
+    assertEquals(worker.getId(), reWorker.getId());
-
+    assertEquals(worker.getName(), reWorker.getName());
-    databaseManager.getObject(9);
-
-    databaseManager.close();
   }
 
   @Test
-  @DisplayName("Assert that a simple Task could be inserted into the database")
+  @DisplayName("Clearing the database (Task and Worker) test")
-  public void assertInsertTask() throws SQLException {
+  public void clearDatabaseTest() throws SQLException, InterruptedException {
+    Task task1 = new Task(10, 5, "Hello", "World");
+    Task task2 = new Task(9, 4, "Hochschule", "Heilbronn");
+    Task task3 = new Task(8, 9, "Gangnam", "Style");
+    Collection<Task> tasks = List.of(task1, task2, task3);
 
-    Task testTask = new Task(1, 1, "Hello World", "Description");
+    Worker worker1 = new Worker("ABC", 2);
+    Worker worker2 = new Worker("XYZ", 9);
+    Collection<Worker> workers = List.of(worker1, worker2);
 
-    databaseManager.connect();
+    databaseManager.saveTasks(tasks);
-    databaseManager.saveObject(testTask);
+    databaseManager.saveWorkers(workers);
-    databaseManager.close();
-  }
 
-  @Test
+    Thread.sleep(500);
-  @DisplayName("Assert that multiple Tasks could be inserted into the database")
-  public void assertInsertMultipleTasks() throws SQLException {
 
-    Task testTaskZero = new Task(1, 1, "Hello", "Description");
+    assertEquals(tasks.size(), databaseManager.getTotalNumberOfTasks());
-    Task testTaskOne = new Task(2, 2, "World", "Description");
+    assertEquals(workers.size(), databaseManager.getTotalNumberOfWorkers());
-    Task testTaskTwo = new Task(3, 3, "Hello World", "Description");
 
-    Collection<Task> tasks = new ArrayList<>();
+    databaseManager.clearDatabase();
-    tasks.add(testTaskZero);
-    tasks.add(testTaskOne);
-    tasks.add(testTaskTwo);
 
-    databaseManager.connect();
+    assertEquals(0, databaseManager.getTotalNumberOfTasks());
-    databaseManager.saveObjects(tasks);
+    assertEquals(0, databaseManager.getTotalNumberOfWorkers());
-    databaseManager.close();
-  }
-
-  @Test
-  @DisplayName("Assert insert object and update it")
-  public void assertInsertUpdateTask() throws SQLException {
-
-    int taskId = 1;
-
-    Task testTask = new Task(taskId, 1, "Hello World", "Description");
-    Task newTask = new Task(taskId, 1, "No World", "Description");
-
-    databaseManager.connect();
-    databaseManager.saveObject(testTask);
-    newTask = databaseManager.updateObject(testTask.getTaskId(), newTask);
-
-    assertNotNull(testTask);
-
-    assertNotEquals(testTask.getDescription(), newTask.getDescription());
-    assertEquals(testTask.getTaskId(), newTask.getTaskId());
-
-    databaseManager.close();
   }
 }