playbindings

Type Members

1. trait PlayBindings[V, W] extends AnyRef

   

2. trait PlayValueWrapper[V, W] extends AnyRef

   

   This trait defines implicits for the common Play Framework transformations on values.

   This trait defines implicits for the common Play Framework transformations on values. Namely: - A Reads[W] to read from json - A Writes[W] to write to json - A PathBindable to convert to and from strings in the url pattern - A QueryStringBindable to convert to and from url query parameters

   To use this with, for instance, a case class that extends AnyVal, create a companion object that extends this trait with V being the primitive type (e.g. String, Int) and W being the wrapped type. Then make an implicit instance of ValueWrapper[V,W] within the companion object, defining the appropriate wrap and unwrap methods.

3. trait SimpleWrapper[V, W] extends ValidatingWrapper[V, W]

   

4. trait ValidatingWrapper[V, W] extends PlayValueWrapper[V, W]

   

5. trait ValueWrapper[V, W] extends AnyRef

   

   Defines an interface that can take a value of type V and wrap it in an instance of type W, and take a W and unwrap it to a V.

   Defines an interface that can take a value of type V and wrap it in an instance of type W, and take a W and unwrap it to a V.

   For example, if W is case class Foo(value:String) extends AnyVal then we can create an instance of ValueWrapper as:

   implicit val FooValueWrapper extends ValueWrapper[String, Foo] {
     def wrap(v:String) : Either[String, Foo] = Right(Foo(v))
     def unwrap(f:Foo) = foo.value
   }

   The wrap method returns Either[String, W] to allow for situations where the V being passed in cannot be converted to a W.

   By making this a type class we can re-use instances of it in a number of places, for example to remove a great deal of boilerplace when creating instances of Play Framework json formatters and url path binders for case classes that extend AnyVal

   V

   the type of the value that is being wrapped

   W

   the type of the wrapper instance