/interpreter/tags/reactive-pattern-matching/src/edu/vub/at/actors/ATActorMirror.java
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 29package edu.vub.at.actors; 30 31import edu.vub.at.exceptions.InterpreterException; 32import edu.vub.at.exceptions.XIllegalOperation; 33import edu.vub.at.objects.ATBoolean; 34import edu.vub.at.objects.ATClosure; 35import edu.vub.at.objects.ATObject; 36import edu.vub.at.objects.ATTable; 37import edu.vub.at.objects.ATTypeTag; 38import edu.vub.at.objects.grammar.ATSymbol; 39 40/** 41 * The class ATActorMirror prescribes the minimal set of methods to be provided by the default 42 * implementation of an actor mirror. Since new actor mirrors can be installed dynamically, 43 * ATActorMirror defines the dependencies of the lexically scoped objects on the dynamic 'actor 44 * context' to perform their duties. The hooks defined in this class relate to: 45 * 46 * <ul> 47 * <li>Asynchronous message creation and sending to influence the communication protocol</li> 48 * <li>Service advertising and requesting to influence the service discovery protocol</li> 49 * <li>Mirror creation to provide support for true stratification</li> 50 * <li>Actor protocol installation to deal with actor mirror interaction and to allow freezing 51 * an actor with a given protocol</li> 52 * </ul> 53 * 54 * @author smostinc 55 */ 56public interface ATActorMirror extends ATObject { 57 58 /* --------------------------------------------------- 59 * -- Language Construct to NATActorMirror Protocol -- 60 * --------------------------------------------------- */ 61 62 /** 63 * Creates a first-class message in the language. Note that upon creation the 64 * message does not have a receiver yet. This field will be set once the message 65 * is actually being sent, a fact which can be intercepted by overriding the sendTo 66 * base-level method. 67 * 68 * @param selector the name of the method to trigger remotely 69 * @param arguments the actual arguments of the message 70 * @param types the types with which the message will be born 71 */ 72 public ATAsyncMessage base_createMessage(ATSymbol selector, ATTable arguments, ATTable types) throws InterpreterException; 73 74 /** 75 * Creates a mirror on the given object. This method serves as the 'mirror factory' 76 * for the current actor. 77 */ 78 public ATObject base_createMirror(ATObject onObject) throws InterpreterException; 79 80 /** 81 * This method implements the default asynchronous message sending semantics for 82 * this particular actor. In addition to the ability to override the send meta- 83 * operation on a single object to have specific adaptions, this hook allows the 84 * programmer to modify the message sending semantics for all objects inside an 85 * actor. The default implementation ensures the correct passing of messages when 86 * they transgress the boundaries of the sending actor. 87 * 88 * @throws InterpreterException 89 */ 90 public ATObject base_send(ATObject receiver, ATAsyncMessage message) throws InterpreterException; 91 92 /** 93 * When an actor receives an asynchronous message for a given receiver, it will delegate this 94 * to the meta-level 'receive' operation of the designated object. This operation is introduced 95 * as a mechanism to alter the semantics of message reception for all objects contained in an 96 * actor. It can be used e.g. to keep track of all succesfully processed messages. 97 */ 98 public ATObject base_receive(ATObject receiver, ATAsyncMessage message) throws InterpreterException; 99 100 /** 101 * This method provides access to a snapshot of the inbox of an actor. It is however not causally 102 * connected to the inbox; adding/removing elements to/from this snapshot will not affect the inbox of 103 * the actor. 104 * @return a table containing all letters that are scheduled to be processed 105 */ 106 public ATTable base_listIncomingLetters() throws InterpreterException; 107 108 /** 109 * This mechanism allows for changing the scheduling semantics of the actor's inbox. 110 * @return a letter, which can be canceled again 111 */ 112 public ATObject base_schedule(ATObject receiver, ATAsyncMessage message) throws InterpreterException; 113 114 /** 115 * This method fetches and processes the next letter from the inbox. 116 * It should take into account the possibility that the inbox is empty. 117 */ 118 public ATObject base_serve() throws InterpreterException; 119 120 /** 121 * This method provides access to a snapshot of the current published services of an actor. 122 * The result is not causally connected; adding/removing elements to/from this snapshot will 123 * not affect the current publications. 124 * @return a table containing all publications of this actor 125 */ 126 public ATTable base_listPublications() throws InterpreterException; 127 128 /** 129 * This method provides access to a snapshot of the current subscriptions of an actor. 130 * The result is not causally connected; adding/removing elements to/from this snapshot will 131 * not affect the current subscriptions. 132 * @return a table containing all subscriptions of this actor 133 */ 134 public ATTable base_listSubscriptions() throws InterpreterException; 135 136 /** 137 * This mechanism is the most basic mechanism to provide a service. It requires 138 * a separate service description and an object offering the service. The return 139 * value is a publication object which allows cancelling the service offer. 140 */ 141 public ATObject base_provide(ATTypeTag topic, ATObject service) throws InterpreterException; 142 143 /** 144 * This mechanism is the most basic mechanism to require a service. The return 145 * value is a subscription object which allows cancelling the service offer. 146 * @param bool - if true, the subscription is permanent, if false, once the subscription 147 * has been satisfied, it is automatically cancelled. 148 */ 149 public ATObject base_require(ATTypeTag topic, ATClosure handler, ATBoolean bool) throws InterpreterException; 150 151 /** 152 * Create a far reference to a local object. Custom actor mirrors may override 153 * this method in order to return different kinds of object references, e.g. 154 * leased object references. 155 * 156 * @param toObject a **near** reference to the object to export 157 * @return a local far reference to the object being exported 158 * @throws XIllegalOperation if the passed object is a far reference, i.e. non-local 159 */ 160 public ATObject base_createReference(ATObject toObject) throws InterpreterException; 161 162 /** 163 * def oldprotocol := actor.becomeMirroredBy: newprotocol 164 * 165 * Installs a new meta-object protocol into this actor. 166 * 167 * @param protocol meta-level code that overrides an actor's MOP methods 168 * @return the previously installed meta-object protocol 169 */ 170 public ATObject base_becomeMirroredBy_(ATActorMirror protocol) throws InterpreterException; 171 172 /** 173 * def aM := implicitActorMirror.getExplicitActorMirror() 174 * 175 * This method serves as the 'mirror factory' for explicit actor mirrors. 176 * 177 * @return an explicit actor mirror for the current actor. 178 */ 179 public ATActorMirror base_getExplicitActorMirror() throws InterpreterException; 180 181 /* ------------------------------------- 182 * -- Object Passing Protocol Support -- 183 * ------------------------------------- */ 184 185 /** 186 * This mechanism interacts with the built-in receptionists set of the actor to 187 * produce a new far object reference to a local object. The created far object 188 * is by no means unique within the actor that created it. 189 * 190 * Creating such far references is performed when passing objects by reference 191 * in the meta_pass method of scoped objects such as closures, objects and fields. 192 * 193 * @param object the local object to be given a reference to 194 * @return a newly created far object reference 195 * 196 * @see edu.vub.at.objects.ATObject#meta_pass(ATFarReference) 197 */ 198 //public ATFarReference base_export(ATObject object) throws InterpreterException; 199 200 /** 201 * This mechanism interacts with the built-in receptionists set of the actor to 202 * resolve far references (which were received as part of an async message). The 203 * method returns a local object whenever the far object denotes an object 204 * hosted by this actor. 205 * 206 * If the denoted object is not hosted by this actor, a far object (possibly but 207 * not necessarily the passed one) is returned which is the local and unique 208 * representative of the remote object. This object will contain the queue of 209 * messages to be transmitted to the remote object. 210 * 211 * @param farReference the far reference to be resolved 212 * @return a local object | a unique far reference for this actor 213 */ 214 //public ATObject base_resolve(ATFarReference farReference) throws InterpreterException; 215 216}