In scala 2.10 we can do like this import scala.reflect.runtime.universe val runtimeMirror = universe.runtimeMirror(getClass.getClassLoader) val module = runtimeMirror.staticModule(“package.ObjectName”) val obj = runtimeMirror.reflectModule(module) println(obj.instance)
In your case, Java reflection might be enough: you can use MyClass::class.java and create a new instance in the same way as you would with Java reflection (see @IngoKegel’s answer). But in case there’s more than one constructor and you really need to get the primary one (not the default no-arg one), use the primaryConstructor … Read more
def companion[T](name : String)(implicit man: Manifest[T]) : T = Class.forName(name + “$”).getField(“MODULE$”).get(man.erasure).asInstanceOf[T] val result = companion[SomeTrait](“SomeObject”).someMethod
From what I understand, you want something like: func IsZeroOfUnderlyingType(x interface{}) bool { return x == reflect.Zero(reflect.TypeOf(x)).Interface() } When talking about interfaces and nil, people always get confused with two very different and unrelated things: A nil interface value, which is an interface value that doesn’t have an underlying value. This is the zero value … Read more
The difference in these two constructs is that, for an expression foo of static (declared or inferred) type Foo: foo.javaClass is typed as Class<Foo> foo::class.java is typed as Class<out Foo> In fact, the latter is more precise, because the actual value that foo evaluates to can be an instance of not Foo itself but one … Read more
This should work: typedefof<System.IEnumerable<_>> EDIT As Tomas notes, there’s nothing special about the _ wildcard here; F# infers that the type obj is the most general applicable type in this context, so this is the same as using typedefof<System.IEnumerable<obj>>. In some cases the way this works can be a bit of a hindrance, though. For … Read more
A good example of how to parse values is the fmt package. See this code. Using the mentioned code to match your problem would look like this: switch val.Kind() { case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: m[typeField.Name] = strconv.FormatInt(val.Int(), 10) case reflect.String: m[typeField.Name] = val.String() // etc… } Basically you need to check for all … Read more
You don’t need to pass in the whole struct, but passing in the value of one of the fields is not sufficient. In your example user.name field is just a string – the reflect package will have no way of correlating that back to the original struct. Instead, you need to pass around the reflect.StructField … Read more
dump() For example println “ddd”.dump() Prints: java.lang.String@2ef900 value=dddd offset=0 count=4 hash=3078400
There is an easier way to invoke method reflectively without resorting to calling Java reflection methods: use Structural Typing. Just cast the object reference to a Structural Type which has the necessary method signature then call the method: no reflection necessary (of course, Scala is doing reflection underneath but we don’t need to do it). … Read more