Scala example source code file (AnyRef.scala)

This example Scala source code file (AnyRef.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

any, anyref, boolean, class, int, long, string, t, unit

The AnyRef.scala Scala example source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2002-2013, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */

package scala

/** Class `AnyRef` is the root class of all ''reference types''.
 *  All types except the value types descend from this class.
 *  @template
 */
trait AnyRef extends Any {

  /** The equality method for reference types.  Default implementation delegates to `eq`.
   *
   *  See also `equals` in [[scala.Any]].
   *
   *  @param  that    the object to compare against this object for equality.
   *  @return         `true` if the receiver object is equivalent to the argument; `false` otherwise.
   */
  def equals(that: Any): Boolean = this eq that

  /** The hashCode method for reference types.  See hashCode in [[scala.Any]].
   *
   *  @return   the hash code value for this object.
   */
  def hashCode: Int = sys.error("hashCode")

  /** Creates a String representation of this object.  The default
   *  representation is platform dependent.  On the java platform it
   *  is the concatenation of the class name, "@", and the object's
   *  hashcode in hexadecimal.
   *
   *  @return     a String representation of the object.
   */
  def toString: String = sys.error("toString")

  /** Executes the code in `body` with an exclusive lock on `this`.
   *
   *  @param    body    the code to execute
   *  @return           the result of `body`
   */
  def synchronized[T](body: => T): T

  /** Tests whether the argument (`arg0`) is a reference to the receiver object (`this`).
   *
   *  The `eq` method implements an [[http://en.wikipedia.org/wiki/Equivalence_relation equivalence relation]] on
   *  non-null instances of `AnyRef`, and has three additional properties:
   *
   *   - It is consistent: for any non-null instances `x` and `y` of type `AnyRef`, multiple invocations of
   *     `x.eq(y)` consistently returns `true` or consistently returns `false`.
   *   - For any non-null instance `x` of type `AnyRef`, `x.eq(null)` and `null.eq(x)` returns `false`.
   *   - `null.eq(null)` returns `true`.
   *
   *  When overriding the `equals` or `hashCode` methods, it is important to ensure that their behavior is
   *  consistent with reference equality.  Therefore, if two objects are references to each other (`o1 eq o2`), they
   *  should be equal to each other (`o1 == o2`) and they should hash to the same value (`o1.hashCode == o2.hashCode`).
   *
   *  @param  that    the object to compare against this object for reference equality.
   *  @return         `true` if the argument is a reference to the receiver object; `false` otherwise.
   */
  final def eq(that: AnyRef): Boolean = sys.error("eq")

  /** Equivalent to `!(this eq that)`.
   *
   *  @param  that    the object to compare against this object for reference equality.
   *  @return         `true` if the argument is not a reference to the receiver object; `false` otherwise.
   */
  final def ne(that: AnyRef): Boolean = !(this eq that)

  /** The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.
   *
   *  @param    arg0  the object to compare against this object for equality.
   *  @return         `true` if the receiver object is equivalent to the argument; `false` otherwise.
   */
  final def ==(that: Any): Boolean =
    if (this eq null) that.asInstanceOf[AnyRef] eq null
    else this equals that

  /** Create a copy of the receiver object.
   *
   *  The default implementation of the `clone` method is platform dependent.
   *
   *  @note   not specified by SLS as a member of AnyRef
   *  @return a copy of the receiver object.
   */
  protected def clone(): AnyRef

  /** Called by the garbage collector on the receiver object when there
   *  are no more references to the object.
   *
   *  The details of when and if the `finalize` method is invoked, as
   *  well as the interaction between `finalize` and non-local returns
   *  and exceptions, are all platform dependent.
   *
   *  @note   not specified by SLS as a member of AnyRef
   */
  protected def finalize(): Unit

  /** A representation that corresponds to the dynamic class of the receiver object.
   *
   *  The nature of the representation is platform dependent.
   *
   *  @note   not specified by SLS as a member of AnyRef
   *  @return a representation that corresponds to the dynamic class of the receiver object.
   */
  def getClass(): Class[_]

  /** Wakes up a single thread that is waiting on the receiver object's monitor.
   *
   *  @note   not specified by SLS as a member of AnyRef
   */
  def notify(): Unit

  /** Wakes up all threads that are waiting on the receiver object's monitor.
   *
   *  @note   not specified by SLS as a member of AnyRef
   */
  def notifyAll(): Unit

  /** Causes the current Thread to wait until another Thread invokes
   *  the notify() or notifyAll() methods.
   *
   *  @note   not specified by SLS as a member of AnyRef
   */
  def wait (): Unit
  def wait (timeout: Long, nanos: Int): Unit
  def wait (timeout: Long): Unit
}