A Printer is just a trait that transforms a String into a String, as shown here:
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trait Printer { |
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def print(name: String): String |
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} |
We currently have a FieldLister that provides a way to list the column names for a case class:
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trait FieldLister[A] { |
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val list: List[String] |
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} |
We need to refactor it to make use of an implicit Printer instead of using the actual case class field name here:
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FieldLister[FieldType[K, H] :: T](witness.value.name :: tLister.list) |
We also need to adapt Unit Tests to this new implementation. The tests are located here:
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"insert" should { |
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"generate a right statement for a regular case class" in { |
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import FieldLister._ |
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StatementGenerator[A].insert("A") shouldBe "INSERT INTO A (a1,a2,a3) VALUES (?,?,?)" |
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} |
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"generate a right statement for a case class with another embedded case class" in { |
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import FieldLister._ |
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StatementGenerator[C].insert("C") shouldBe "INSERT INTO C (c1,c2) VALUES (?,?)" |
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} |
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"generate a right expanded statement for a case class with another embedded case class" in { |
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import StatementGenerator._ |
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import FieldListerExpanded._ |
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StatementGenerator[C].insert("C") shouldBe "INSERT INTO C (c1,b1,b2) VALUES (?,?,?)" |
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} |
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} |
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"select" should { |
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"generate a right statement for a regular case class" in { |
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import FieldLister._ |
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StatementGenerator[A].select("A") shouldBe "SELECT a1,a2,a3 FROM A" |
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} |
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"generate a right statement for a case class with another embedded case class" in { |
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import FieldLister._ |
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StatementGenerator[C].select("C") shouldBe "SELECT c1,c2 FROM C" |
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} |
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"generate a right expanded statement for a case class with another embedded case class" in { |
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import FieldListerExpanded._ |
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StatementGenerator[C].select("C") shouldBe "SELECT c1,b1,b2 FROM C" |
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} |
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} |
An example of the behavior we are looking for can be found here:
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implicit def hconsFromReader[K <: Symbol, V, L <: HList]( |
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implicit |
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witness: Witness.Aux[K], |
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codec: ByteBufferCodec[V], |
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grT: FromReader[L], |
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printer: Printer): FromReader[FieldType[K, V] :: L] = |
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new FromReader[FieldType[K, V] :: L] { |
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override def apply[M[_]](reader: ByteBufferReader)( |
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implicit ME: MonadError[M, Throwable]): M[FieldType[K, V] :: L] = { |
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val newName = printer.print(witness.value.name) |
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ME.flatMap(reader.read(newName)) { byteBuffer => |
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ME.map2(codec.deserialize(byteBuffer), grT(reader)) { |
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case (result, l) => new FieldBuilder[K].apply(result) :: l |
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} |
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} |
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} |
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} |