Object Fields Transfer (OCopy)

This library simplify object's fields coping. For example you have 2 different case classes: EntityObject and DataTransferObject. Each of them has independent set of fields and you want to transparently transfer data from one object to another without huge handwritten copy methods.

This library built on top of scala macros and requires scala 2.11

SBT

 resolvers += Resolver.bintrayRepo("lembrd", "maven")
 libraryDependencies += "org.lembrd" %% "ocopy-lib" % "1.12"

Use case

class OCopyTest extends FlatSpec with Matchers {

  "OCopy" should "transfer complex classes" in {
    val from = ClassOne(field1 =  "f1", field2 = "f2", field3 = Another("a","b"), field4_1 = 0.1d, field4_2 = 42, userId = Some(UserId(0)), f5 = 50)
    val mergeSource = ClassToBeMerged(mergedField = 113L)

    // implicit def conversion
    implicit def userIdToLong(x:UserId) : Long = x.id

    val to : ClassTwo = transfer(from)
      .to[ClassTwo]
//    .mergeAllFrom( mergeSource )  // append fields from object mergeSource
      .mergeExclude(mergeSource)(_.field1, _.fieldExclude2) // append fields from object mergeSource with exclusion checking
      .assign(_.outsideField).fromOutside( Random.nextLong() )  // append field from outside
//    automatically:  field1 copied by default (name and types equal)
//    automatically:  .assign(_.f5).from(_.f5) // using Option wrapper
//    automatically:  userId => _.userId.id // using implicit def [UserId] -> [Long] and wrapped by Option.map
      .assign(_.f4).using(_.field1){ x => x.length} // using inline converter
      .assign(_.field3).from(_.field3.f1) // using long path
      .assign(_.field4).usingSelf{ x => new Complex2(x.field4_1, x.field4_2)} // complex object mapping instead of one field
      .build
/*
The actual generated code is:

new org.lembrd.ocopy.test.ClassTwo(
  f4 = ((x: String) => x.length())(((x$5: org.lembrd.ocopy.test.ClassOne) => x$5.field1)(from)),
  field4 = ((x: org.lembrd.ocopy.test.ClassOne) => new Complex2(x.field4_1, x.field4_2))(from),
  field1 = from.field1,
  mergedField = mergeSource.mergedField,
  userId = from.userId.map(((ftnx0) => ftnx0)),
  outsideField = org.lembrd.ocopy.`package`.conversions.anyToOption[Long](scala.util.Random.nextLong()),
  field3 = ((x$7: org.lembrd.ocopy.test.ClassOne) => x$7.field3.f1)(from),
  f5 = from.f5)
 */
    println(to)

    to.field1 shouldBe "f1"
    to.field3 shouldBe "a"
    to.userId shouldBe Some(0L)
  }
}





case class ClassOne(field1      : String,
                    field2      : String,
                    field3      : Another,
                    field4_1    : Double,
                    field4_2    : Int,
                    userId      : Option[UserId],
                    f5          : Int
                   )
case class ClassToBeMerged(
                            mergedField : Long,
                            fieldExclude2 : String = "",
                            field1 : String = ""
                          )
case class ClassTwo(userId: Option[Long],
                    field1 : String,
                    field3 : String,
                    mergedField : Long,
                    f4 : Int,
                    f5 : Option[Long],
                    field4 : Complex2,
                    outsideField : Option[Long]
                   )

case class Another(f1 : String, f2 : String)
class Complex2(d1 : Double, d2 : Int)

case class UserId(id : Long) extends AnyVal