edu.vub.at.actors.natives
Class NATActorMirror

java.lang.Object
  edu.vub.at.objects.natives.NATNil
      edu.vub.at.objects.natives.NATByRef
          edu.vub.at.actors.natives.NATActorMirror

All Implemented Interfaces:

ATAbstractGrammar, ATActorMirror, ATConversions, ATExpression, ATNil, ATObject, ATStatement, java.io.Serializable

public class NATActorMirror

extends NATByRef

implements ATActorMirror

The NATActorMirror class implements the concurrency model of ambienttalk. It continually consumes meta-events which are written to a synchronized queue. This way the actor is notified of incoming messages, discovered and lost services, etc. When no meta- messages are available, the actor consumes base-level messages as they are stored in its inbox. These messages have a receiver object internal to the actor and they will be invoked on this receiver by the actor's thread.

Author:

smostinc

See Also:

Serialized Form

Nested Class Summary

static class	NATActorMirror.NATProtocol A protocol object is defined as: object: { def installedMirror := //the installed actor mirror; def uninstall() { //uninstall the protocol object } }
static class	NATActorMirror.NATPublication A publication object is defined as: object: { def topic := //topic under which service is published; def service := //the exported service object; def cancel() { //unexport the service object } }
static class	NATActorMirror.NATSubscription A subscription object is defined as: object: { def topic := //topic subscribed to; def handler := //the closure to be triggered; def cancel() { //unsubscribe the handler } }

Field Summary

private ELDiscoveryActor

discoveryActor_

Fields inherited from class edu.vub.at.objects.natives.NATNil

_INSTANCE_

Fields inherited from interface edu.vub.at.actors.ATActorMirror

_IN_, _OUT_, _PROVIDED_, _REQUIRED_

Constructor Summary

NATActorMirror(ELVirtualMachine host)
When initializing a new actor, do not forget that this constructor is still executed by the creating actor, not by the created actor.

Method Summary

ATActorMirror	base_asActorMirror()
ATAsyncMessage	base_createMessage(ATObject sender, ATSymbol selector, ATTable arguments) Creates a first-class message in the language.
ATObject	base_install_(ATClosure code) def install: { code }
ATObject	base_provide(ATStripe topic, ATObject service) This mechanism is the most basic mechanism to provide a service.
ATObject	base_require(ATStripe topic, ATClosure handler, ATBoolean isPermanent) This mechanism is the most basic mechanism to require a service.
ATObject	base_send(ATAsyncMessage message) When default base-level objects send an asynchronous message, they delegate this responsibility to their actor by means of this base-level method.
static NATLocalFarRef	createActor(ELVirtualMachine host, Packet parametersPkt, Packet initcodePkt, ATActorMirror actorMirror) Creates a new actor on the specified host Virtual Machine.
static NATLocalFarRef	createEmptyActor(ELVirtualMachine host, ATActorMirror actorMirror) Auxiliary creation method to create an actor with an empty behaviour.
ATObject	meta_clone() Clone the receiver object.
ATTable	meta_getStripes() Returns the stripes of this object.
ATObject	meta_newInstance(ATTable initargs) actor.new(closure) => same effect as evaluating 'actor: closure'
NATText	meta_print() Prints out the object in a human-readable way.
ATObject	meta_receive(ATAsyncMessage msg) Handles a first-class message of which it is the receiver.
ATObject	meta_send(ATAsyncMessage msg) To send a message msg to a receiver object rcv: - if rcv is a local reference, schedule accept(msg) in my incoming event queue - if rcv is a far reference, schedule msg in far reference's outbox

Methods inherited from class edu.vub.at.objects.natives.NATByRef

meta_pass, meta_resolve

Methods inherited from class edu.vub.at.objects.natives.NATNil

asAmbientTalkObject, asJavaClassUnderSymbiosis, asJavaObjectUnderSymbiosis, asNativeBoolean, asNativeException, asNativeFarReference, asNativeFraction, asNativeNumber, asNativeNumeric, asNativeTable, asNativeText, base__opeql__opeql_, base_asAsyncMessage, base_asBegin, base_asBoolean, base_asClosure, base_asDefinition, base_asExpression, base_asFarReference, base_asField, base_asHandler, base_asMessage, base_asMessageCreation, base_asMethod, base_asMirror, base_asNumber, base_asSplice, base_asStatement, base_asStripe, base_asSymbol, base_asTable, base_asUnquoteSplice, base_asVariableAssignment, base_init, base_isBoolean, base_isCallFrame, base_isClosure, base_isFarReference, base_isMessageCreation, base_isMethod, base_isMirror, base_isSplice, base_isStripe, base_isSymbol, base_isTable, base_isUnquoteSplice, base_isVariableAssignment, base_new, createChild, equals, isAmbientTalkObject, isJavaObjectUnderSymbiosis, isNativeBoolean, isNativeField, isNativeText, meta_addField, meta_addMethod, meta_assignField, meta_assignVariable, meta_defineField, meta_doesNotUnderstand, meta_eval, meta_extend, meta_getDynamicParent, meta_getLexicalParent, meta_grabField, meta_grabMethod, meta_invoke, meta_isCloneOf, meta_isRelatedTo, meta_isStripedWith, meta_listFields, meta_listMethods, meta_lookup, meta_quote, meta_respondsTo, meta_select, meta_share, readResolve, toString, writeReplace

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface edu.vub.at.objects.ATObject

base__opeql__opeql_, base_init, base_new, meta_addField, meta_addMethod, meta_assignField, meta_assignVariable, meta_defineField, meta_doesNotUnderstand, meta_eval, meta_extend, meta_getDynamicParent, meta_getLexicalParent, meta_grabField, meta_grabMethod, meta_invoke, meta_isCloneOf, meta_isRelatedTo, meta_isStripedWith, meta_listFields, meta_listMethods, meta_lookup, meta_pass, meta_quote, meta_resolve, meta_respondsTo, meta_select, meta_share

Methods inherited from interface edu.vub.at.objects.coercion.ATConversions

asAmbientTalkObject, asJavaClassUnderSymbiosis, asJavaObjectUnderSymbiosis, asNativeBoolean, asNativeException, asNativeFarReference, asNativeFraction, asNativeNumber, asNativeNumeric, asNativeTable, asNativeText, base_asAsyncMessage, base_asBegin, base_asBoolean, base_asClosure, base_asDefinition, base_asExpression, base_asFarReference, base_asField, base_asHandler, base_asMessage, base_asMessageCreation, base_asMethod, base_asMirror, base_asNumber, base_asSplice, base_asStatement, base_asStripe, base_asSymbol, base_asTable, base_asUnquoteSplice, base_asVariableAssignment, base_isBoolean, base_isCallFrame, base_isClosure, base_isFarReference, base_isMessageCreation, base_isMethod, base_isMirror, base_isSplice, base_isStripe, base_isSymbol, base_isTable, base_isUnquoteSplice, base_isVariableAssignment, isAmbientTalkObject, isJavaObjectUnderSymbiosis, isNativeBoolean, isNativeField, isNativeText

Field Detail

discoveryActor_

private final ELDiscoveryActor discoveryActor_

Constructor Detail

NATActorMirror

public NATActorMirror(ELVirtualMachine host)

When initializing a new actor, do not forget that this constructor is still executed by the creating actor, not by the created actor. To make the created actor perform something, it is necessary to use meta_receive to send itself messages for later execution.

Method Detail

createActor

public static NATLocalFarRef createActor(ELVirtualMachine host,
                                         Packet parametersPkt,
                                         Packet initcodePkt,
                                         ATActorMirror actorMirror)
                                  throws InterpreterException

Creates a new actor on the specified host Virtual Machine. The actor its behaviour is intialized by means of the passed parameters and initialization code. The calling thread is **blocked** until the actor has been constructed. However, actor behaviour and root initialization is carried out by the newly created actor itself.

Parameters:

host - the VM hosting this actor - after creation, the actor registers itself with this VM

parametersPkt - the serialized parameters used to invoke the initialization code

initcodePkt - the serialized initialization code used to initialize the actor behaviour

actorMirror - this actor's mirror

Returns:

a far reference to the behaviour of the actor

Throws:

InterpreterException

createEmptyActor

public static NATLocalFarRef createEmptyActor(ELVirtualMachine host,
                                              ATActorMirror actorMirror)
                                       throws InterpreterException

Auxiliary creation method to create an actor with an empty behaviour. Equivalent to evaluating: actor: { nil }

Throws:

InterpreterException

base_createMessage

public ATAsyncMessage base_createMessage(ATObject sender,
                                         ATSymbol selector,
                                         ATTable arguments)
                                  throws InterpreterException

Description copied from interface: ATActorMirror

Creates a first-class message in the language. Note that upon creation the message does not have a receiver yet. This field will be set once the message is actually being sent, a fact which can be intercepted by overriding the sendTo base-level method.

Specified by:

base_createMessage in interface ATActorMirror

Throws:

InterpreterException

base_provide

public ATObject base_provide(ATStripe topic,
                             ATObject service)
                      throws InterpreterException

Description copied from interface: ATActorMirror

This mechanism is the most basic mechanism to provide a service. It requires a separate service description and an object offering the service. The return value is a publication object which allows cancelling the service offer.

Specified by:

base_provide in interface ATActorMirror

Throws:

InterpreterException

base_require

public ATObject base_require(ATStripe topic,
                             ATClosure handler,
                             ATBoolean isPermanent)
                      throws InterpreterException

Description copied from interface: ATActorMirror

This mechanism is the most basic mechanism to require a service. The return value is a subscription object which allows cancelling the service offer.

Specified by:

base_require in interface ATActorMirror

Parameters:

isPermanent - - if true, the subscription is permanent, if false, once the subscription has been satisfied, it is automatically cancelled.

Throws:

InterpreterException

meta_clone

public ATObject meta_clone()
                    throws InterpreterException

Description copied from interface: ATObject

Clone the receiver object. This cloning closely corresponds to the allocation phase in class-based OO languages. In class-based languages, instance creation is based on the equation = () (i.e. first allocate a new instance, then initialize it). In our object-based model, allocation is replaced by cloning. When an object is asked to clone itself, it will also clone its dynamic parent if it extends this parent in an 'is-a' relationship. This is similar to the observation that, in class-based languages, allocating a new object of a subclass entails allocating space for the state of the superclass. Triggers the objectCloned event on this object's beholders (mirror observers). Initializing the clone is the responsibility of the method named .

Specified by:

meta_clone in interface ATObject

Overrides:

meta_clone in class NATNil

Throws:

InterpreterException

meta_newInstance

public ATObject meta_newInstance(ATTable initargs)
                          throws InterpreterException

actor.new(closure) => same effect as evaluating 'actor: closure'

Specified by:

meta_newInstance in interface ATObject

Overrides:

meta_newInstance in class NATNil

Throws:

InterpreterException

meta_print

public NATText meta_print()
                   throws InterpreterException

Description copied from interface: ATObject

Prints out the object in a human-readable way.

Specified by:

meta_print in interface ATObject

Overrides:

meta_print in class NATNil

Throws:

InterpreterException

meta_send

public ATObject meta_send(ATAsyncMessage msg)
                   throws InterpreterException

To send a message msg to a receiver object rcv: - if rcv is a local reference, schedule accept(msg) in my incoming event queue - if rcv is a far reference, schedule msg in far reference's outbox

Specified by:

meta_send in interface ATObject

Overrides:

meta_send in class NATNil

Throws:

InterpreterException

meta_receive

public ATObject meta_receive(ATAsyncMessage msg)
                      throws InterpreterException

Description copied from interface: ATObject

Handles a first-class message of which it is the receiver.

Specified by:

meta_receive in interface ATObject

Overrides:

meta_receive in class NATNil

Throws:

InterpreterException

meta_getStripes

public ATTable meta_getStripes()
                        throws InterpreterException

Description copied from interface: ATObject

Returns the stripes of this object. Note that only the stripes that were attached directly to this object are returned, not all of the parent's stripes as well.

Specified by:

meta_getStripes in interface ATObject

Overrides:

meta_getStripes in class NATNil

Throws:

InterpreterException

base_send

public ATObject base_send(ATAsyncMessage message)
                   throws InterpreterException

When default base-level objects send an asynchronous message, they delegate this responsibility to their actor by means of this base-level method. The actor's base-level 'send' operation dispatches to its meta-level 'send' operation. In effect, the semantics of an object sending an async message are the same as those of an actor sending an async message directly. TODO(discuss) is this the desirable semantics for the base-level hook?

Specified by:

base_send in interface ATActorMirror

Throws:

InterpreterException

base_install_

public ATObject base_install_(ATClosure code)
                       throws InterpreterException

def install: { code }

Specified by:

base_install_ in interface ATActorMirror

Parameters:

code - meta-level code that overrides an actor's MOP methods

Returns:

a protocol object that allows to uninstall the MOP code

Throws:

InterpreterException

See Also:

Technically, this MOP installation is achieved by performing an imperative mixin operation on the actor's mirror.

base_asActorMirror

public ATActorMirror base_asActorMirror()
                                 throws XTypeMismatch

Specified by:

base_asActorMirror in interface ATConversions

Overrides:

base_asActorMirror in class NATNil

Throws:

XTypeMismatch