Scala example source code file (annotations.scala)

This example Scala source code file (annotations.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

array, beanproperty, beanproperty, c, count, foo, int, int, integer, sourceannotation, sourceannotation, string, string, unit

The Scala annotations.scala source code

object Test1 {
  class Foo {
    @remote
    def foo: Unit = ()
  }
  def run {
    val method = classOf[Foo].getMethod("foo")
    method.getExceptionTypes foreach println
  }
}

object Test2 {
  import java.io.{BufferedReader,FileReader, IOException}
  class Reader(fname: String) {
    private val in = new BufferedReader(new FileReader(fname))

    @throws(classOf[IOException])
    def read() = in.read()
  }
  def run {
    val method = classOf[Reader].getMethod("read")
    method.getExceptionTypes foreach println
  }
}

/* Java:
public class Main {
    @Deprecated
    public void foo() {}
    public static void main(String[] args) throws Exception {
        Method method = Class.forName("test.Main").getMethod("foo", new Class[]{});
        Annotation annotation = method.getAnnotation(Deprecated.class);
        System.out.println(annotation); // @java.lang.Deprecated()
    }
}
*/
object Test3 {
  import java.lang.Deprecated
  class Foo {
    @Deprecated
    def foo: Unit = ()
  }
  def run {
    val method = classOf[Foo].getMethod("foo")
    val annotation = method.getAnnotation(classOf[Deprecated])
    println(annotation)
  }
}

/* Java:
@Retention(value=RetentionPolicy.RUNTIME)
@interface Source {
   public String url();
   public String mail();
}
@Source(url="http://scala.epfl.ch", mail="scala@lists.epfl.ch")
class Foo {}
public class Main {
    public static void main(String[] args) throws Exception {
        Class clazz = Class.forName("test.Foo");
        Annotation[] annotations = clazz.getAnnotations();
        for (int i = 0; i < annotations.length; i++)
            System.out.println(annotations[i]);
        // @test.Main$Source(url=http://scala-lang.org, mail=scala@lists.epfl.ch)
    }
}
*/
object Test4 {
  import test.SourceAnnotation // defined in SourceAnnotation.java
  @SourceAnnotation(value = "http://scala-lang.org",
                    mails = Array("scala@lists.epfl.ch", "scala-lounge@lists.epfl.ch"))
  class Foo1
  @SourceAnnotation(value = "http://bloodsuckers.com",
                    mails = Array("you@bloodsuckers.com"))
  class Foo2
  @SourceAnnotation("http://bloodsuckers.com")
  class Foo3
  class Foo4 {
    @SourceAnnotation("file:///dev/null")
    val x = 1
  }
  class Foo5 {
    @SourceAnnotation("file:///dev/zero")
    def bar: Int = 0
  }
  class Foo6 @SourceAnnotation("primary constructor") (s: String) {
    // to guarantee that primary constructor annotations
    // are not applied to secondary constructors
    def this() = this("")
  }
  class Foo7(s: String) {
    @SourceAnnotation("secondary constructor")
    def this() = this("")
  }
  class Foo8(@SourceAnnotation("constructor val") val n: Int) {}
  class Foo9 {
    import scala.annotation.target._
    import scala.reflect.BeanProperty
    @(SourceAnnotation @getter)("http://apple.com") val x = 0
    @BeanProperty @(SourceAnnotation @beanSetter)("http://uppla.com") var y = 0

    type myAnn = SourceAnnotation @beanGetter @field
    @BeanProperty @myAnn("http://eppli.com") var z = 0
  }
  class Foo10(@SourceAnnotation("on param 1") val name: String)
  class Foo11(@(SourceAnnotation @scala.annotation.target.field)("on param 2") val name: String)
  class Foo12(@(SourceAnnotation @scala.annotation.target.setter)("on param 3") var name: String)
  def run {
    import java.lang.annotation.Annotation
    import java.lang.reflect.AnnotatedElement
    def printSourceAnnotation(a: Annotation) {
      val ann = a.asInstanceOf[SourceAnnotation]
      println("@test.SourceAnnotation(mails=" + ann.mails.deepMkString("{", ",", "}") +
              ", value=" + ann.value + ")")
    }
    def printSourceAnnotations(target: AnnotatedElement) {
      //print SourceAnnotation in a predefined way to insure
      // against difference in the JVMs (e.g. Sun's vs IBM's)
      val anns = target.getAnnotations()
      anns foreach printSourceAnnotation
      if (anns.length > 0) {
        println(target)
        println
      }
    }
    def printParamSourceAnnotations(target: { def getParameterAnnotations(): Array[Array[Annotation]] }) {
      val anns = target.getParameterAnnotations().flatten
      anns foreach printSourceAnnotation
      if (anns.length > 0) {
        println(target)
        println
      }
    }
    printSourceAnnotations(classOf[Foo1])
    printSourceAnnotations(classOf[Foo2])
    printSourceAnnotations(classOf[Foo3])
    classOf[Foo4].getDeclaredFields  foreach printSourceAnnotations
    classOf[Foo4].getDeclaredMethods foreach printSourceAnnotations
    classOf[Foo5].getDeclaredMethods foreach printSourceAnnotations
    classOf[Foo6].getDeclaredConstructors foreach printSourceAnnotations
    classOf[Foo7].getDeclaredConstructors foreach printSourceAnnotations
    classOf[Foo8].getDeclaredFields  foreach printSourceAnnotations
    classOf[Foo8].getDeclaredMethods foreach printSourceAnnotations
    classOf[Foo8].getDeclaredConstructors foreach printParamSourceAnnotations
    classOf[Foo9].getDeclaredFields.sortWith((x, y) => x.toString < y.toString)  foreach printSourceAnnotations
    classOf[Foo9].getDeclaredMethods.sortWith((x, y) => x.toString < y.toString) foreach printSourceAnnotations
    classOf[Foo10].getDeclaredFields.sortWith((x, y) => x.toString < y.toString)  foreach printSourceAnnotations
    classOf[Foo10].getDeclaredMethods.sortWith((x, y) => x.toString < y.toString) foreach printSourceAnnotations
    classOf[Foo10].getDeclaredConstructors foreach printParamSourceAnnotations
    classOf[Foo11].getDeclaredFields.sortWith((x, y) => x.toString < y.toString)  foreach printSourceAnnotations
    classOf[Foo11].getDeclaredMethods.sortWith((x, y) => x.toString < y.toString) foreach printSourceAnnotations
    classOf[Foo11].getDeclaredConstructors foreach printParamSourceAnnotations
    classOf[Foo12].getDeclaredFields.sortWith((x, y) => x.toString < y.toString)  foreach printSourceAnnotations
    classOf[Foo12].getDeclaredMethods.sortWith((x, y) => x.toString < y.toString) foreach printSourceAnnotations
    classOf[Foo12].getDeclaredConstructors foreach printParamSourceAnnotations
  }
}

object Test5 {
  import scala.reflect.BeanProperty
  import java.lang.Integer

  class Count {
    // we use "Integer" instead of "Int" because of Java reflection
    @BeanProperty
    var count: Integer = 0

    private val getter =
      getClass().getMethod("getCount")
    private val setter =
      getClass().getMethod("setCount", classOf[Integer])

    def get = getter.invoke(this).asInstanceOf[Integer].intValue
    def set(n: Int) = setter.invoke(this, new Integer(n))
  }
  def run {
    val count = new Count
    println(count.get)
    count.set(99)
    println(count.get)
  }
}

object Test6 {
  import scala.reflect.BeanProperty
  import scala.reflect.BooleanBeanProperty
  class C(@BeanProperty var text: String)
  class D(@BooleanBeanProperty var prop: Boolean) {
    @BeanProperty val m: Int = if (prop) 1 else 2
  }

  def run {
    val c = new C("bob")
    c.setText("dylan")
    println(c.getText())
    if (new D(true).isProp()) {
      println(new D(false).getM())
    }
  }
}

// #3345
class A3345(@volatile private var i:Int)

object Test {
  def main(args: Array[String]) {
    Test1.run
    Test2.run
    Test3.run     // requires the use of -target:jvm-1.5
    Test4.run
    Test5.run
    Test6.run
  }
}