selectEntry available for both Doobie and Slick modules

core/src/main/scala/za/co/absa/fadb/DBFunctionFabric.scala

@@ -21,15 +21,13 @@ package za.co.absa.fadb
  *  that offer certain implementations. This trait should help with the inheritance of all of these
  */
 abstract class DBFunctionFabric(functionNameOverride: Option[String])(implicit val schema: DBSchema) {
-
   /**
-   *  List of fields to select from the DB function.
-   *  @return - list of fields to select
+   * Alias of the function, based on the class name
    */
-  def fieldsToSelect: Seq[String] = Seq.empty
+  protected val alias = "FNC"
 
   /**
-   *  Name of the function, based on the class name, unless it is overridden in the constructor
+   * Name of the function, based on the class name, unless it is overridden in the constructor
    */
   val functionName: String = {
     val fn = functionNameOverride.getOrElse(schema.objectNameFromClassName(getClass))
@@ -40,4 +38,26 @@ abstract class DBFunctionFabric(functionNameOverride: Option[String])(implicit v
     }
   }
 
+  /**
+   *  List of fields to select from the DB function.
+   *  @return - list of fields to select
+   */
+  def fieldsToSelect: Seq[String] = Seq.empty
+
+  /*
+    *  Generates a list of select columns for the function
+   */
+  protected def selectEntry: String = {
+    val fieldsSeq = fieldsToSelect
+    if (fieldsSeq.isEmpty) {
+      "*"
+    } else {
+      val aliasToUse = if (alias.isEmpty) {
+        ""
+      } else {
+        s"$alias."
+      }
+      fieldsToSelect.map(aliasToUse + _).mkString(",")
+    }
+  }
 }

doobie/src/it/scala/za/co/absa/fadb/doobie/DoobieSingleResultFunctionTest.scala

@@ -30,8 +30,13 @@ class DoobieSingleResultFunctionTest extends AnyFunSuite with DoobieTest {
   class CreateActor(implicit schema: DBSchema, dbEngine: DoobieEngine[IO])
       extends DoobieSingleResultFunction[CreateActorRequestBody, Int, IO] {
 
+    // do not remove the example below
+    // override def fieldsToSelect: Seq[String] = super.fieldsToSelect ++ Seq("o_actor_id")
+
     override def sql(values: CreateActorRequestBody)(implicit read: Read[Int]): Fragment =
       sql"SELECT o_actor_id FROM ${Fragment.const(functionName)}(${values.firstName}, ${values.lastName})"
+      // do not remove the example below, it has to be used with the override def fieldsToSelect
+      // sql"SELECT ${Fragment.const(selectEntry)} FROM ${Fragment.const(functionName)}(${values.firstName}, ${values.lastName}) ${Fragment.const(alias)}"
   }
 
   private val createActor = new CreateActor()(Runs, new DoobieEngine(transactor))

doobie/src/main/scala/za/co/absa/fadb/doobie/DoobieFunction.scala

@@ -27,7 +27,6 @@ import za.co.absa.fadb.{DBFunctionWithStatus, DBSchema, FunctionStatusWithData}
 import scala.language.higherKinds
 
 trait DoobieFunctionBase[R] {
-
   /**
    *  The `Read[R]` instance used to read the query result into `R`.
    */
@@ -41,7 +40,6 @@ trait DoobieFunctionBase[R] {
  *  @tparam R the result type of the function
  */
 private[doobie] trait DoobieFunction[I, R] extends DoobieFunctionBase[R] {
-
   /**
    *  Generates a Doobie `Fragment` representing the SQL query for the function.
    *
@@ -60,9 +58,6 @@ private[doobie] trait DoobieFunction[I, R] extends DoobieFunctionBase[R] {
 }
 
 private[doobie] trait DoobieFunctionWithStatus[I, R] extends DoobieFunctionBase[R] {
-
-  def checkStatus[A](statusWithData: FunctionStatusWithData[A]): Either[StatusException, A]
-
   /**
    *  The `Read[StatusWithData[R]]` instance used to read the query result with status into `StatusWithData[R]`.
    */
@@ -85,14 +80,16 @@ private[doobie] trait DoobieFunctionWithStatus[I, R] extends DoobieFunctionBase[
    *  @return the `DoobieQueryWithStatus[R]` representing the SQL query
    */
   protected def query(values: I): DoobieQueryWithStatus[R] = new DoobieQueryWithStatus[R](sql(values), checkStatus)
+
+  // This is to be mixed in by an implementation of StatusHandling
+  def checkStatus[A](statusWithData: FunctionStatusWithData[A]): Either[StatusException, A]
 }
 
 /**
  *  `DoobieFunction` is an object that contains several abstract classes extending different types of database functions.
  *  These classes use Doobie's `Fragment` to represent SQL queries and `DoobieEngine` to execute them.
  */
 object DoobieFunction {
-
   /**
    *  `DoobieSingleResultFunctionWithStatus` is an abstract class that extends `DBSingleResultFunctionWithStatus` with `DoobiePgEngine` as the engine type.
    *  It represents a database function that returns a single result with status.

slick/src/main/scala/za/co/absa/fadb/slick/SlickFunction.scala

@@ -32,7 +32,6 @@ import scala.concurrent.Future
  *  @tparam R the result type of the function
  */
 private[slick] trait SlickFunctionBase[I, R] {
-
   /**
    *  The `GetResult[R]` instance used to read the query result into `R`.
    */
@@ -47,34 +46,9 @@ private[slick] trait SlickFunctionBase[I, R] {
   protected def sql(values: I): SQLActionBuilder
 
   def fieldsToSelect: Seq[String]
-
-  /**
-   *  Alias to use within the SQL query
-   */
-  protected val alias = "FNC"
-
-  /**
-   *  Helper function to use in the actual DB function class
-   *
-   *  @return the SELECT part of the function call SQL query
-   */
-  protected def selectEntry: String = {
-    val fieldsSeq = fieldsToSelect
-    if (fieldsSeq.isEmpty) {
-      "*"
-    } else {
-      val aliasToUse = if (alias.isEmpty) {
-        ""
-      } else {
-        s"$alias."
-      }
-      fieldsToSelect.map(aliasToUse + _).mkString(",")
-    }
-  }
 }
 
 private[slick] trait SlickFunction[I, R] extends SlickFunctionBase[I, R] {
-
   /**
    *  Generates a `SlickQuery[R]` representing the SQL query for the function.
    *
@@ -85,7 +59,6 @@ private[slick] trait SlickFunction[I, R] extends SlickFunctionBase[I, R] {
 }
 
 private[slick] trait SlickFunctionWithStatus[I, R] extends SlickFunctionBase[I, R] {
-
   /**
    * Generates a `SlickQueryWithStatus[R]` representing the SQL query for the function with status support.
    *
@@ -100,7 +73,6 @@ private[slick] trait SlickFunctionWithStatus[I, R] extends SlickFunctionBase[I,
 }
 
 object SlickFunction {
-
   /**
    *  Class for Slick DB functions with status support.
    */