Frames.EN.md

The tool for incomplete data representation - synapse-frames

Key features

1. Entity attribute declaration for arbitrary types.
2. Natural type hierarchy declaration (using all Scala's features).
3. Complete separation of data and schema. The data can be stored in a flat List[Any] or Array and then checked and converted to a strict typed construction.
4. Typed representation of instances.

A simple schema example

Let's have a few types (that can include type aliases, traits, classes, object.types, etc.):

    abstract class Shape
    trait BoundingRectangle
    final class Rectangle extends Shape with BoundingRectangle
    final class Circle extends Shape with BoundingRectangle

We can bind properties to any type:

    object BoundingRectangleS extends PropertySeq[BoundingRectangle] {
      val width = simpleProperty[Int]("width")
      val height = simpleProperty[Int]("height")
    }
    import BoundingRectangleS._

    object CircleS extends PropertySeq[Circle] {
      importProperties(BoundingRectangleS.toSchema)
      val radius = Rel[Circle, Int]("radius")
    }
    import CircleS._

Properties bound to parent types can be used freely for descendent types.

In the above example we have collected properties within a PropertySeq descendent. This allows us to immediately have full schema of corresponding type (CircleS.toSchema). Also we can declare a property outside of the schema-object:

    val name = Rel[Shape, String]("name")

It is possible to have different schemas bound to the same type depending on the application requirements.

    val onlyBoundingRectSchema = BoundingRectangleS.toSchema
    
    val someInfoAboutACircle = record[Circle](radius)
    val fullInfoAboutACircle = someInfoAboutACircle ++ onlyBoundingRectSchema

Data instances (records, frame instances) can be constructed using builder:

    val circ10 = new Builder(someInfoAboutACircle).
      set(radius, simple(10)).
      toInstance
    val shape10 = new Builder(fullInfoAboutACircle).
      fillFromInstance(circ10).
      set(width, simple(10)).
      set(height, simple(10)).
      toInstance
    assert(shape10.get(radius) === circ10.get(radius))

At runtime one can make sure that some instances meets a schema:

    assert(isMatching(shape10, someInfoAboutACircle))
    assert(isMatching(shape10, fullInfoAboutACircle))
    assert(isMatching(circ10 , someInfoAboutACircle))
    assert(nonMatching(circ10 , fullInfoAboutACircle))

Getting started

The current version of the library is "ru.primetalk:synapse-frames_2.10:1.3.3".