polish + exception (iluwatar#79)

active-record/src/main/java/com/iluwatar/activerecord/App.java

@@ -1,12 +1,14 @@
 package com.iluwatar.activerecord;
 
+import java.sql.Connection;
 import java.sql.SQLException;
+import java.sql.Statement;
 import javax.sql.DataSource;
 import lombok.extern.slf4j.Slf4j;
 import org.h2.jdbcx.JdbcDataSource;
 
 /**
- * The amin application for the manual testing purposes.
+ * The main application for the manual testing purposes.
  */
 @Slf4j
 public class App {
@@ -35,10 +37,10 @@ public class App {
    * Java main method to execute all the logic out there.
    *
    * @param args arguments.
-   * @throws Exception Any sort of exception that have to be picked up by the JVM.
+   * @throws Exception Any sort of exception that has to be picked up by the JVM.
    */
   public static void main(final String[] args) throws Exception {
-    final var dataSource = createDataSource();
+    final DataSource dataSource = createDataSource();
     createSchema(dataSource);
     RecordBase.setDataSource(dataSource);
     executeOperation();
@@ -65,14 +67,14 @@ private static void executeOperation() {
   }
 
   private static void createSchema(DataSource dataSource) throws SQLException {
-    try (var connection = dataSource.getConnection();
-        var statement = connection.createStatement()) {
-      statement.execute(CREATE_SCHEMA_SQL);
+    try (Connection conn = dataSource.getConnection();
+        Statement stmt = conn.createStatement()) {
+      stmt.execute(CREATE_SCHEMA_SQL);
     }
   }
 
   private static DataSource createDataSource() {
-    var dataSource = new JdbcDataSource();
+    JdbcDataSource dataSource = new JdbcDataSource();
     dataSource.setURL(DB_URL);
     return dataSource;
   }

active-record/src/main/java/com/iluwatar/activerecord/RecordBase.java

@@ -9,7 +9,6 @@
 import java.util.List;
 import javax.sql.DataSource;
 import lombok.RequiredArgsConstructor;
-import lombok.Setter;
 
 /**
  * An active record base supposed to hold all the necessary active record pattern logic.
@@ -24,17 +23,31 @@ public abstract class RecordBase<T extends RecordBase<?>> {
 
   private static final String EXCEPTION_MESSAGE = "Couldn't execute database query for the following domain model :";
 
-  @Setter
   private static DataSource dataSource;
 
   @SuppressWarnings({"unchecked"})
   private final Class<T> clazz = (Class<T>) getClass();
 
+  /**
+   * Sets the data source. Preferably to eb done during the application startup or within the
+   * configuration.
+   *
+   * @param dataSource the data source {@link DataSource}.
+   */
+  public static void setDataSource(DataSource dataSource) {
+    RecordBase.dataSource = dataSource;
+  }
+
+  /**
+   * Get an SQL exception for the sake of all other internal persistence methods.
+   *
+   * @return the connection {@link Connection}.
+   */
   protected Connection getConnection() {
     try {
       return dataSource.getConnection();
     } catch (SQLException e) {
-      throw new RuntimeException("Unable to acquire database connection", e);
+      throw new RecordDataAccessException("Unable to acquire database connection", e);
     }
   }
 
@@ -45,8 +58,20 @@ protected Connection getConnection() {
    */
   protected abstract String getTableName();
 
+  /**
+   * Set all the fields into the underlying domain model from the result set.
+   *
+   * @param rs the result set {@link ResultSet}.
+   * @throws SQLException an SQL exception.
+   */
   protected abstract void setFieldsFromResultSet(ResultSet rs) throws SQLException;
 
+  /**
+   * Set the prepared statement parameters for the SQL statement to insert/update record.
+   *
+   * @param pstmt prepared statement {@link PreparedStatement}.
+   * @throws SQLException an SQL exception.
+   */
   protected abstract void setPreparedStatementParams(PreparedStatement pstmt) throws SQLException;
 
   /**
@@ -67,7 +92,7 @@ public List<T> findAll() {
         return recordList;
       }
     } catch (SQLException e) {
-      throw new RuntimeException(EXCEPTION_MESSAGE + clazz.getName(), e);
+      throw new RecordDataAccessException(EXCEPTION_MESSAGE + clazz.getName(), e);
     }
   }
 
@@ -90,7 +115,8 @@ public T findById(Long id) {
         return getDeclaredClassInstance();
       }
     } catch (SQLException e) {
-      throw new RuntimeException(EXCEPTION_MESSAGE + clazz.getName() + " with id=" + id, e);
+      throw new RecordDataAccessException(EXCEPTION_MESSAGE + clazz.getName() + " with id=" + id,
+          e);
     }
   }
 
@@ -107,20 +133,18 @@ public void save() {
       pstmt.executeUpdate();
 
     } catch (SQLException e) {
-      throw new RuntimeException(EXCEPTION_MESSAGE + clazz.getName(), e);
+      throw new RecordDataAccessException(EXCEPTION_MESSAGE + clazz.getName(), e);
     }
   }
 
+  private String constructFindByIdQuery() {
+    return constructFindAllQuery() + " WHERE id = ?";
+  }
 
   private String constructFindAllQuery() {
     return "SELECT * FROM " + getDeclaredClassInstance().getTableName();
   }
 
-  private String constructFindByIdQuery() {
-    return "SELECT * FROM " + getDeclaredClassInstance().getTableName()
-        + " WHERE id = ?";
-  }
-
   private T getDeclaredClassInstance() {
     try {
       return clazz.getDeclaredConstructor().newInstance();

active-record/src/main/java/com/iluwatar/activerecord/RecordDataAccessException.java

@@ -0,0 +1,19 @@
+package com.iluwatar.activerecord;
+
+public class RecordDataAccessException extends RuntimeException {
+
+  public RecordDataAccessException() {
+  }
+
+  public RecordDataAccessException(String message) {
+    super(message);
+  }
+
+  public RecordDataAccessException(String message, Throwable cause) {
+    super(message, cause);
+  }
+
+  public RecordDataAccessException(Throwable cause) {
+    super(cause);
+  }
+}