Scala example source code file (package.scala)

This example Scala source code file (package.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

annotation

The package.scala Scala example source code

package scala.annotation

/**
 * When defining a field, the Scala compiler creates up to four accessors
 * for it: a getter, a setter, and if the field is annotated with
 * `@BeanProperty`, a bean getter and a bean setter.
 *
 * For instance in the following class definition
 *
 * {{{
 * class C(@myAnnot @BeanProperty var c: Int)
 * }}}
 *
 * there are six entities which can carry the annotation `@myAnnot`: the
 * constructor parameter, the generated field and the four accessors.
 *
 * By default, annotations on (`val`-, `var`- or plain) constructor parameters
 * end up on the parameter, not on any other entity. Annotations on fields
 * by default only end up on the field.
 *
 * The meta-annotations in package `scala.annotation.meta` are used
 * to control where annotations on fields and class parameters are copied.
 * This is done by annotating either the annotation type or the annotation
 * class with one or several of the meta-annotations in this package.
 *
 * ==Annotating the annotation type==
 *
 * The target meta-annotations can be put on the annotation type when
 * instantiating the annotation. In the following example, the annotation
 * `@Id` will be added only to the bean getter `getX`.
 *
 * {{{
 * import javax.persistence.Id
 * class A {
 *   @(Id @beanGetter) @BeanProperty val x = 0
 * }
 * }}}
 *
 * In order to annotate the field as well, the meta-annotation `@field`
 * would need to be added.
 *
 * The syntax can be improved using a type alias:
 *
 * {{{
 * object ScalaJPA {
 *   type Id = javax.persistence.Id @beanGetter
 * }
 * import ScalaJPA.Id
 * class A {
 *   @Id @BeanProperty val x = 0
 * }
 * }}}
 *
 * ==Annotating the annotation class==
 *
 * For annotations defined in Scala, a default target can be specified
 * in the annotation class itself, for example
 *
 * {{{
 * @getter
 * class myAnnotation extends Annotation
 * }}}
 *
 * This only changes the default target for the annotation `myAnnotation`.
 * When instantiating the annotation, the target can still be specified
 * as described in the last section.
 */
package object meta