/interpreter/tags/reactive-pattern-matching/src/edu/vub/at/actors/ATActorMirror.java

http://ambienttalk.googlecode.com/ · Java · 216 lines · 25 code · 22 blank · 169 comment · 0 complexity · 5e3a3fc3635b0c6841541cbd752d8082 MD5 · raw file

  1. /**
  2. * AmbientTalk/2 Project
  3. * ATActorMirror.java created on Aug 21, 2006
  4. * (c) Programming Technology Lab, 2006 - 2007
  5. * Authors: Tom Van Cutsem & Stijn Mostinckx
  6. *
  7. * Permission is hereby granted, free of charge, to any person
  8. * obtaining a copy of this software and associated documentation
  9. * files (the "Software"), to deal in the Software without
  10. * restriction, including without limitation the rights to use,
  11. * copy, modify, merge, publish, distribute, sublicense, and/or
  12. * sell copies of the Software, and to permit persons to whom the
  13. * Software is furnished to do so, subject to the following
  14. * conditions:
  15. *
  16. * The above copyright notice and this permission notice shall be
  17. * included in all copies or substantial portions of the Software.
  18. *
  19. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  20. * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  21. * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  22. * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  23. * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  24. * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  25. * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  26. * OTHER DEALINGS IN THE SOFTWARE.
  27. */
  28. package edu.vub.at.actors;
  29. import edu.vub.at.exceptions.InterpreterException;
  30. import edu.vub.at.exceptions.XIllegalOperation;
  31. import edu.vub.at.objects.ATBoolean;
  32. import edu.vub.at.objects.ATClosure;
  33. import edu.vub.at.objects.ATObject;
  34. import edu.vub.at.objects.ATTable;
  35. import edu.vub.at.objects.ATTypeTag;
  36. import edu.vub.at.objects.grammar.ATSymbol;
  37. /**
  38. * The class ATActorMirror prescribes the minimal set of methods to be provided by the default
  39. * implementation of an actor mirror. Since new actor mirrors can be installed dynamically,
  40. * ATActorMirror defines the dependencies of the lexically scoped objects on the dynamic 'actor
  41. * context' to perform their duties. The hooks defined in this class relate to:
  42. *
  43. * <ul>
  44. * <li>Asynchronous message creation and sending to influence the communication protocol</li>
  45. * <li>Service advertising and requesting to influence the service discovery protocol</li>
  46. * <li>Mirror creation to provide support for true stratification</li>
  47. * <li>Actor protocol installation to deal with actor mirror interaction and to allow freezing
  48. * an actor with a given protocol</li>
  49. * </ul>
  50. *
  51. * @author smostinc
  52. */
  53. public interface ATActorMirror extends ATObject {
  54. /* ---------------------------------------------------
  55. * -- Language Construct to NATActorMirror Protocol --
  56. * --------------------------------------------------- */
  57. /**
  58. * Creates a first-class message in the language. Note that upon creation the
  59. * message does not have a receiver yet. This field will be set once the message
  60. * is actually being sent, a fact which can be intercepted by overriding the sendTo
  61. * base-level method.
  62. *
  63. * @param selector the name of the method to trigger remotely
  64. * @param arguments the actual arguments of the message
  65. * @param types the types with which the message will be born
  66. */
  67. public ATAsyncMessage base_createMessage(ATSymbol selector, ATTable arguments, ATTable types) throws InterpreterException;
  68. /**
  69. * Creates a mirror on the given object. This method serves as the 'mirror factory'
  70. * for the current actor.
  71. */
  72. public ATObject base_createMirror(ATObject onObject) throws InterpreterException;
  73. /**
  74. * This method implements the default asynchronous message sending semantics for
  75. * this particular actor. In addition to the ability to override the send meta-
  76. * operation on a single object to have specific adaptions, this hook allows the
  77. * programmer to modify the message sending semantics for all objects inside an
  78. * actor. The default implementation ensures the correct passing of messages when
  79. * they transgress the boundaries of the sending actor.
  80. *
  81. * @throws InterpreterException
  82. */
  83. public ATObject base_send(ATObject receiver, ATAsyncMessage message) throws InterpreterException;
  84. /**
  85. * When an actor receives an asynchronous message for a given receiver, it will delegate this
  86. * to the meta-level 'receive' operation of the designated object. This operation is introduced
  87. * as a mechanism to alter the semantics of message reception for all objects contained in an
  88. * actor. It can be used e.g. to keep track of all succesfully processed messages.
  89. */
  90. public ATObject base_receive(ATObject receiver, ATAsyncMessage message) throws InterpreterException;
  91. /**
  92. * This method provides access to a snapshot of the inbox of an actor. It is however not causally
  93. * connected to the inbox; adding/removing elements to/from this snapshot will not affect the inbox of
  94. * the actor.
  95. * @return a table containing all letters that are scheduled to be processed
  96. */
  97. public ATTable base_listIncomingLetters() throws InterpreterException;
  98. /**
  99. * This mechanism allows for changing the scheduling semantics of the actor's inbox.
  100. * @return a letter, which can be canceled again
  101. */
  102. public ATObject base_schedule(ATObject receiver, ATAsyncMessage message) throws InterpreterException;
  103. /**
  104. * This method fetches and processes the next letter from the inbox.
  105. * It should take into account the possibility that the inbox is empty.
  106. */
  107. public ATObject base_serve() throws InterpreterException;
  108. /**
  109. * This method provides access to a snapshot of the current published services of an actor.
  110. * The result is not causally connected; adding/removing elements to/from this snapshot will
  111. * not affect the current publications.
  112. * @return a table containing all publications of this actor
  113. */
  114. public ATTable base_listPublications() throws InterpreterException;
  115. /**
  116. * This method provides access to a snapshot of the current subscriptions of an actor.
  117. * The result is not causally connected; adding/removing elements to/from this snapshot will
  118. * not affect the current subscriptions.
  119. * @return a table containing all subscriptions of this actor
  120. */
  121. public ATTable base_listSubscriptions() throws InterpreterException;
  122. /**
  123. * This mechanism is the most basic mechanism to provide a service. It requires
  124. * a separate service description and an object offering the service. The return
  125. * value is a publication object which allows cancelling the service offer.
  126. */
  127. public ATObject base_provide(ATTypeTag topic, ATObject service) throws InterpreterException;
  128. /**
  129. * This mechanism is the most basic mechanism to require a service. The return
  130. * value is a subscription object which allows cancelling the service offer.
  131. * @param bool - if true, the subscription is permanent, if false, once the subscription
  132. * has been satisfied, it is automatically cancelled.
  133. */
  134. public ATObject base_require(ATTypeTag topic, ATClosure handler, ATBoolean bool) throws InterpreterException;
  135. /**
  136. * Create a far reference to a local object. Custom actor mirrors may override
  137. * this method in order to return different kinds of object references, e.g.
  138. * leased object references.
  139. *
  140. * @param toObject a **near** reference to the object to export
  141. * @return a local far reference to the object being exported
  142. * @throws XIllegalOperation if the passed object is a far reference, i.e. non-local
  143. */
  144. public ATObject base_createReference(ATObject toObject) throws InterpreterException;
  145. /**
  146. * def oldprotocol := actor.becomeMirroredBy: newprotocol
  147. *
  148. * Installs a new meta-object protocol into this actor.
  149. *
  150. * @param protocol meta-level code that overrides an actor's MOP methods
  151. * @return the previously installed meta-object protocol
  152. */
  153. public ATObject base_becomeMirroredBy_(ATActorMirror protocol) throws InterpreterException;
  154. /**
  155. * def aM := implicitActorMirror.getExplicitActorMirror()
  156. *
  157. * This method serves as the 'mirror factory' for explicit actor mirrors.
  158. *
  159. * @return an explicit actor mirror for the current actor.
  160. */
  161. public ATActorMirror base_getExplicitActorMirror() throws InterpreterException;
  162. /* -------------------------------------
  163. * -- Object Passing Protocol Support --
  164. * ------------------------------------- */
  165. /**
  166. * This mechanism interacts with the built-in receptionists set of the actor to
  167. * produce a new far object reference to a local object. The created far object
  168. * is by no means unique within the actor that created it.
  169. *
  170. * Creating such far references is performed when passing objects by reference
  171. * in the meta_pass method of scoped objects such as closures, objects and fields.
  172. *
  173. * @param object the local object to be given a reference to
  174. * @return a newly created far object reference
  175. *
  176. * @see edu.vub.at.objects.ATObject#meta_pass(ATFarReference)
  177. */
  178. //public ATFarReference base_export(ATObject object) throws InterpreterException;
  179. /**
  180. * This mechanism interacts with the built-in receptionists set of the actor to
  181. * resolve far references (which were received as part of an async message). The
  182. * method returns a local object whenever the far object denotes an object
  183. * hosted by this actor.
  184. *
  185. * If the denoted object is not hosted by this actor, a far object (possibly but
  186. * not necessarily the passed one) is returned which is the local and unique
  187. * representative of the remote object. This object will contain the queue of
  188. * messages to be transmitted to the remote object.
  189. *
  190. * @param farReference the far reference to be resolved
  191. * @return a local object | a unique far reference for this actor
  192. */
  193. //public ATObject base_resolve(ATFarReference farReference) throws InterpreterException;
  194. }