scalabeans

Ah, turns out I missed the up-to-date discussion here:
http://code.google.com/p/scalabeans/wiki/Blog. I checked out the
development branch, and now I get the right results. See test
definition below for what I was interested in. This is great software!

Minor quibbles: Should the primitive type names be capitalized? And
that blog is somewhat hidden on the scalabeans main page, at least
from me.

Cheers,

Andreas

package org.scalastuff.scalabeans

import org.junit.{Assert, Test}
import org.scalastuff.scalabeans.types._

class OptionRefTest {
@Test
def testCreate {
def test[T<:AnyRef:Manifest](tn: String) {
val bd = Preamble.descriptorOf[T]
Assert.assertEquals(4, bd.properties.length)
val ns = Seq("String", "double", "int", "boolean")
for ( (n, i) <- ns.zipWithIndex)
Assert.assertEquals(tn+"["+n+"]",
""+bd.properties(i).scalaType)
}
test[OptionTestBean]("Option")
test[RefTestBean]("Ref")
}
}

case class OptionTestBean(
stringOpt: Option[String], doubleOpt: Option[Double],
intOpt: Option[Int], booleanOpt: Option[Boolean]
)
case class RefTestBean(
stringOpt: Ref[String], doubleOpt: Ref[Double],
intOpt: Ref[Int], booleanOpt: Ref[Boolean]
)
case class Ref[T](x: T)

On Jul 29, 10:51 pm, Andreas W wrote:
> I have decided to look into scalabeans for an introspection need that
> I have. I have found it ingeniously straightforward and simple, a
> wonderful design. It seems much underused, as I have found very little
> on the web except its web sites and an occasional general comment
> about it. Apparently, you can introspect with it beyond erasure by use
> of Manifests, and from early experiments I have found that, for
> example, properties like prop: Option[SomeClass] are correctly
> detected. I had, however, a property of type "Option[Double]" which
> was apparently introspected as "Option[Object]". This puts a huge dent
> in my enthusiasm, as this is the kind of type I need to resolve. Is
> this a known behavior, or have I done something wrong?
>
> I have
>
> case class Rec(name: String, value: Double, opt: Option[Double], obj:
> Option[SomeClass])
>
> I do "descriptor[Rec].properties.mkString("\n  ")", and I get types
> out like this:
>
>   String
>   Double
>   Option[Object]
>   Option[SomeClass]
>
> i.e. it correctly represents Option[SomeClass], but not
> Option[Double].
>
> Any ideas what I could be doing wrong?
>
> Thanks,
>
> Andreas

Yeah, 0.2-SNAPSHOT definitely fixes it.

[info] == run ==
[info] Running Main
name : String // tag: 1, readonly
value : double // tag: 2, readonly
opt : Option[double] // tag: 3, readonly
obj : Option[Object] // tag: 4, readonly
[info] == run ==
[success] Successful.

Have you already found some comparison metrics about the impact on the
performance and memory usage?

The only minor thing I could find is that it only works with case
class, not with normal classes

Changing
case class Rec(name: String, value: Double, opt: Option[Double], obj:
Option[SomeClass])
into:
class Rec(name: String, value: Double, opt: Option[Double], obj:
Option[SomeClass])

[info] == run ==
[info] Running Main

[info] == run ==
[success] Successful.

Or I missed something...

> Or I missed something...

Of course
case classes create read-only fields for constructor parameters
implicitly

Using:
class Rec(val name: String, val value: Double, val opt:
Option[Double], val obj: Option[SomeClass])

[info] Running Main
name : String // tag: 1, readonly
value : double // tag: 2, readonly
opt : Option[double] // tag: 3, readonly
obj : Option[Object] // tag: 4, readonly
[info] == run ==
[success] Successful.

Using:
class Rec(var name: String, var value: Double, var opt:
Option[Double], var obj: Option[SomeClass])

[info] == run ==
[info] Running Main
name : String // tag: 1
value : double // tag: 2
opt : Option[double] // tag: 3
obj : Option[Object] // tag: 4
[info] == run ==
[success] Successful.

Hmm, in 0.2-SNAPSHOT is Option[SomeClass] changed to
Option[Object] ...
What dev version did you use?

On Jul 30, 4:35 pm, Dave wrote:
> Hmm, in 0.2-SNAPSHOT is Option[SomeClass] changed to
> Option[Object] ...
> What dev version did you use?

I cloned the repository this morning. For me, the Option[SomeClass]
works, the below test runs without problems.

package org.scalastuff.scalabeans

import org.junit.{Assert, Test}
import org.scalastuff.scalabeans.types._

class OptionRefTest {
@Test
def testCreate {
def test[T<:AnyRef:Manifest](tn: String) {
val bd = Preamble.descriptorOf[T]
val ns = Seq("String", "double", "int", "boolean", "SomeClass")
Assert.assertEquals(ns.length, bd.properties.length)
for ( (n, i) <- ns.zipWithIndex)
Assert.assertEquals(tn+"["+n+"]",
""+bd.properties(i).scalaType)
}
test[OptionTestBean]("Option")
test[RefTestBean]("Ref")
}
}

case class OptionTestBean(
stringOpt: Option[String], doubleOpt: Option[Double],
intOpt: Option[Int], booleanOpt: Option[Boolean],
objOpt: Option[SomeClass]
)
case class RefTestBean(
stringOptRef: Ref[String], doubleRef: Ref[Double],
intRef: Ref[Int], booleanRef: Ref[Boolean],
objRef: Ref[SomeClass]
)
case class Ref[T](x: T)
class SomeClass

It seems that it only works in test mode inside the junit test
framework.
If you run it as a real compiled application Option[SomeClass]is
changed into Option[Object] and also the Refs are type erased.

I am always suspicious about test frameworks because they sometimes
change the behaviour of what you want to test. That is why I always
test it in compiled form outside the test framework.

Or do you have an example that works in compiled form?

test run
========

C:\scala-2.9.1.RC1\examples\erase>java -Xmx512M -jar "c:\sbt\sbt-
launch-0.10.1.j
ar" test
[info] Set current project to default-9123ff (in build file:/C:/
scala-2.9.1.RC1/
examples/erase/)
[info] Compiling 1 Scala source to C:\scala-2.9.1.RC1\examples\erase
\target\scal
a-2.9.1.RC1\classes...
[info] Compiling 1 Scala source to C:\scala-2.9.1.RC1\examples\erase
\target\scal
a-2.9.1.RC1\test-classes...
5==5
Option[String]==Option[String]
Option[double]==Option[double]
Option[int]==Option[int]
Option[boolean]==Option[boolean]
Option[SomeClass]==Option[SomeClass]
5==5
Ref[String]==Ref[String]
Ref[double]==Ref[double]
Ref[int]==Ref[int]
Ref[boolean]==Ref[boolean]
Ref[SomeClass]==Ref[SomeClass]
[info] Passed: : Total 1, Failed 0, Errors 0, Passed 1, Skipped 0
[success] Total time: 9 s, completed 31-jul-2011 13:57:09

compiled run
============

C:\scala-2.9.1.RC1\examples\erase>java -Xmx512M -jar "c:\sbt\sbt-
launch-0.10.1.j
ar" run
[info] Set current project to default-9123ff (in build file:/C:/
scala-2.9.1.RC1/
examples/erase/)
[info] Running Main
5==5
Option[String]==Option[String]
Option[double]==Option[double]
Option[int]==Option[int]
Option[boolean]==Option[boolean]
Option[SomeClass]==Option[Object]
5==5
Ref[String]==Object
Ref[double]==Object
Ref[int]==Object
Ref[boolean]==Object
Ref[SomeClass]==Object
[success] Total time: 2 s, completed 31-jul-2011 13:53:05

erase.scala
===========

import org.scalastuff.scalabeans._
import org.scalastuff.scalabeans.types._

object Main extends App {
def test[T<:AnyRef:Manifest](tn: String) {
val bd = Preamble.descriptorOf[T]
val ns = Seq("String", "double", "int", "boolean",
"SomeClass")
println(ns.length + "==" + bd.properties.length)
for ( (n, i) <- ns.zipWithIndex) {
println(tn+"["+n+"]" + "==" +
bd.properties(i).scalaType)
}
}
test[OptionTestBean]("Option")
test[RefTestBean]("Ref")
}

case class OptionTestBean(
stringOpt: Option[String], doubleOpt: Option[Double],
intOpt: Option[Int], booleanOpt: Option[Boolean],
objOpt: Option[SomeClass]
)
case class RefTestBean(
stringOptRef: Ref[String], doubleRef: Ref[Double],
intRef: Ref[Int], booleanRef: Ref[Boolean],
objRef: Ref[SomeClass]
)
case class Ref[T](x: T)
class SomeClass

Just to be sure I tested also outside of sbt java-only, but it was the
same.

C:\scala-2.9.1.RC1\examples\erase\target\scala-2.9.1.RC1>java -
cp ../../../../li
b/scala-library.jar;google-collect-1.0-
rc2.jar;erase_2.9.1.RC1-1.0.jar;C:\Users\
Dave\.ivy2\cache\org.scalastuff\scalabeans\jars\scalabeans-0.2-
SNAPSHOT.jar;C:\U
sers\Dave\.ivy2\cache\com.thoughtworks.paranamer\paranamer\jars
\paranamer-2.3.ja
r Main
5==5
Option[String]==Option[String]
Option[double]==Option[double]
Option[int]==Option[int]
Option[boolean]==Option[boolean]
Option[SomeClass]==Option[Object]
5==5
Ref[String]==Object
Ref[double]==Object
Ref[int]==Object
Ref[boolean]==Object
Ref[SomeClass]==Object

google-collect-1.0-rc2.jar can be downloaded from:
http://www.java2s.com/Code/Jar/GHI/Downloadgooglecollect10rc2jar.htm

You are right. When I run without JUnit, the below code returns:

Option[String]: Option[String]
Option[double]: Option[Object]
Option[int]: Option[Object]
Option[boolean]: Option[Object]
Option[SomeClass]: Option[SomeClass]
Ref[String]: Ref[String]
Ref[double]: Ref[Object]
Ref[int]: Ref[Object]
Ref[boolean]: Ref[Object]
Ref[SomeClass]: Ref[SomeClass]

A little better than yours, but with the Option[Val] issue not fixed.
Bummer. Not sure what to try next....

By the way, the blog-post that mentioned this issue earlier on the
scalabeans Wiki appears to have disappeared. This is not good.

Andreas

def main(args: Array[String]) {
testBean[OptionTestBean]("Option")
testBean[RefTestBean]("Ref")
}

def testBean[T<:AnyRef:Manifest](tn: String) {
val bd = descriptorOf[T]
val ns = Seq("String", "double", "int", "boolean", "SomeClass")
for ( (n, i) <- ns.zipWithIndex)
println(tn+"["+n+"]: "+bd.properties(i).scalaType)
}

case class OptionTestBean(
stringOpt: Option[String], doubleOpt: Option[Double],
intOpt: Option[Int], booleanOpt: Option[Boolean],
objOpt: Option[SomeClass]
)
case class RefTestBean(
stringOptRef: Ref[String], doubleRef: Ref[Double],
intRef: Ref[Int], booleanRef: Ref[Boolean],
objRef: Ref[SomeClass]
)
case class Ref[T](x: T)
class SomeClass

On Jul 31, 9:04 am, Dave wrote:
> Just to be sure I tested also outside of sbt java-only, but it was the
> same.
>
> C:\scala-2.9.1.RC1\examples\erase\target\scala-2.9.1.RC1>java -
> cp ../../../../li
> b/scala-library.jar;google-collect-1.0-
> rc2.jar;erase_2.9.1.RC1-1.0.jar;C:\Users\
> Dave\.ivy2\cache\org.scalastuff\scalabeans\jars\scalabeans-0.2-
> SNAPSHOT.jar;C:\U
> sers\Dave\.ivy2\cache\com.thoughtworks.paranamer\paranamer\jars
> \paranamer-2.3.ja
> r Main
> 5==5
> Option[String]==Option[String]
> Option[double]==Option[double]
> Option[int]==Option[int]
> Option[boolean]==Option[boolean]
> Option[SomeClass]==Option[Object]
> 5==5
> Ref[String]==Object
> Ref[double]==Object
> Ref[int]==Object
> Ref[boolean]==Object
> Ref[SomeClass]==Object
>
> google-collect-1.0-rc2.jar can be downloaded from:http://www.java2s.com/Code/Jar/GHI/Downloadgooglecollect10rc2jar.htm

Ah, I feel like I have made a breakthrough (of sorts...). The code I
posted was from inside an "object" declaration. On a hunch, I took the
test classes out to the package level, and voila:

Option[String]: Option[String]
Option[double]: Option[double]
Option[int]: Option[int]
Option[boolean]: Option[boolean]
Option[SomeClass]: Option[SomeClass]
Ref[String]: Ref[String]
Ref[double]: Ref[double]
Ref[int]: Ref[int]
Ref[boolean]: Ref[boolean]
Ref[SomeClass]: Ref[SomeClass]

So, it seems scalabeans only works with top-level classes, which is
still bummer, but not a show-stopper....

Andreas

On Aug 2, 3:50 pm, Andreas W wrote:
> You are right. When I run without JUnit, the below code returns:
>
> Option[String]: Option[String]
> Option[double]: Option[Object]
> Option[int]: Option[Object]
> Option[boolean]: Option[Object]
> Option[SomeClass]: Option[SomeClass]
> Ref[String]: Ref[String]
> Ref[double]: Ref[Object]
> Ref[int]: Ref[Object]
> Ref[boolean]: Ref[Object]
> Ref[SomeClass]: Ref[SomeClass]
>
> A little better than yours, but with the Option[Val] issue not fixed.
> Bummer. Not sure what to try next....
>
> By the way, the blog-post that mentioned this issue earlier on the
> scalabeans Wiki appears to have disappeared. This is not good.
>
> Andreas
>
>   def main(args: Array[String]) {
>     testBean[OptionTestBean]("Option")
>     testBean[RefTestBean]("Ref")
>   }
>
>   def testBean[T<:AnyRef:Manifest](tn: String) {
>     val bd = descriptorOf[T]
>     val ns = Seq("String", "double", "int", "boolean", "SomeClass")
>     for ( (n, i) <- ns.zipWithIndex)
>       println(tn+"["+n+"]: "+bd.properties(i).scalaType)
>   }
>
>   case class OptionTestBean(
>       stringOpt: Option[String], doubleOpt: Option[Double],
>       intOpt: Option[Int], booleanOpt: Option[Boolean],
>       objOpt: Option[SomeClass]
>   )
>   case class RefTestBean(
>       stringOptRef: Ref[String], doubleRef: Ref[Double],
>       intRef: Ref[Int], booleanRef: Ref[Boolean],
>       objRef: Ref[SomeClass]
>   )
>   case class Ref[T](x: T)
>   class SomeClass
>
> On Jul 31, 9:04 am, Dave wrote:
>
>
>
>
>
>
>
> > Just to be sure I tested also outside of sbt java-only, but it was the
> > same.
>
> > C:\scala-2.9.1.RC1\examples\erase\target\scala-2.9.1.RC1>java -
> > cp ../../../../li
> > b/scala-library.jar;google-collect-1.0-
> > rc2.jar;erase_2.9.1.RC1-1.0.jar;C:\Users\
> > Dave\.ivy2\cache\org.scalastuff\scalabeans\jars\scalabeans-0.2-
> > SNAPSHOT.jar;C:\U
> > sers\Dave\.ivy2\cache\com.thoughtworks.paranamer\paranamer\jars
> > \paranamer-2.3.ja
> > r Main
> > 5==5
> > Option[String]==Option[String]
> > Option[double]==Option[double]
> > Option[int]==Option[int]
> > Option[boolean]==Option[boolean]
> > Option[SomeClass]==Option[Object]
> > 5==5
> > Ref[String]==Object
> > Ref[double]==Object
> > Ref[int]==Object
> > Ref[boolean]==Object
> > Ref[SomeClass]==Object
>
> > google-collect-1.0-rc2.jar can be downloaded from:http://www.java2s.com/Code/Jar/GHI/Downloadgooglecollect10rc2jar.htm

Yes, that's it. It works here too

package declaration is necessary
and the test classes must be on top level/package level which I
already had (I forgot only declaring package erase).

package declaration is also necessary for the test class (remove it
and it doesn't work anymore).

C:\scala-2.9.1.RC1\examples\erase>sbt run

C:\scala-2.9.1.RC1\examples\erase>set SCRIPT_DIR=c:\sbt\

C:\scala-2.9.1.RC1\examples\erase>java -Xmx512M -jar "c:\sbt\sbt-
launch-0.10.1.j
ar" run
[info] Set current project to default-9123ff (in build file:/C:/
scala-2.9.1.RC1/
examples/erase/)
[info] Running erase.Main
5==5
Option[String]==Option[String]
Option[double]==Option[double]
Option[int]==Option[int]
Option[boolean]==Option[boolean]
Option[SomeClass]==Option[SomeClass]
5==5
Ref[String]==Ref[String]
Ref[double]==Ref[double]
Ref[int]==Ref[int]
Ref[boolean]==Ref[boolean]
Ref[SomeClass]==Ref[SomeClass]
[success] Total time: 2 s, completed 3-aug-2011 2:39:58

C:\scala-2.9.1.RC1\examples\erase>sbt test

C:\scala-2.9.1.RC1\examples\erase>set SCRIPT_DIR=c:\sbt\

C:\scala-2.9.1.RC1\examples\erase>java -Xmx512M -jar "c:\sbt\sbt-
launch-0.10.1.j
ar" test
[info] Set current project to default-9123ff (in build file:/C:/
scala-2.9.1.RC1/
examples/erase/)
[info] Compiling 1 Scala source to C:\scala-2.9.1.RC1\examples\erase
\target\scal
a-2.9.1.RC1\test-classes...
5==5
Option[String]==Option[String]
Option[double]==Option[double]
Option[int]==Option[int]
Option[boolean]==Option[boolean]
Option[SomeClass]==Option[SomeClass]
5==5
Ref[String]==Ref[String]
Ref[double]==Ref[double]
Ref[int]==Ref[int]
Ref[boolean]==Ref[boolean]
Ref[SomeClass]==Ref[SomeClass]
[info] Passed: : Total 1, Failed 0, Errors 0, Passed 1, Skipped 0
[success] Total time: 7 s, completed 3-aug-2011 2:40:20