org.erights.e.elib.ref
Class DisconnectedRef

java.lang.Object
  |
  +--org.erights.e.elib.ref.Ref
        |
        +--org.erights.e.elib.ref.DisconnectedRef

All Implemented Interfaces:

Amplifiable, Callable, Marker, PassByConstruction, Persistent, Serializable

class DisconnectedRef

extends Ref

implements Persistent, PassByConstruction

What a FarRef becomes when it breaks -- a BROKEN Ref with identity.

Maintains the same()ness identity and sameness hash of the FarRef. A DisconnectedRef is listed as an HONORARY Selfless object for implementation reasons only: (HONORARY because it encapsulates its identity, so it isn't transparent).

A DisconnectedRef's contents must be transitively transparently Selfless and passable by construction. DisconnectedRef is listed as implementing PassByConstruction for implementation reasons only. Not being NEAR, by definition it is not a PassByContruction object.

Author:

Mark S. Miller

Field Summary

(package private) Object	myIdentity
private Throwable	myProblem
private static long	serialVersionUID

Fields inherited from class org.erights.e.elib.ref.Ref

BROKEN, EVENTUAL, NEAR, TheViciousRef

Fields inherited from interface org.erights.e.elib.serial.Persistent

HONORARY, HONORED_NAMES

Fields inherited from interface org.erights.e.elib.serial.PassByConstruction

HONORARY, HONORED_NAMES

Constructor Summary

(package private)

DisconnectedRef(Throwable problem, Object identity) Makes a Ref that will never deliver messages to any object because of problem, but which is considered the same() as a particular object.

Method Summary

Object	callAll(String verb, Object[] args) This default implementation switches on state() and either synchronously forward the message, if we're NEAR, or complains.
(package private) void	commit() Used by a resolvers to turn off switchability, and thereby make this Ref equivalent to its current target.
private Throwable	doBreakage(String verb, Object[] args) Should be called only if the state is already BROKEN.
boolean	equals(Object other) As an HONORARY Selfless object, my .equals() and .hashCode() determine sameness.
int	hashCode() As an HONORARY Selfless object, my .equals() and .hashCode() determine sameness.
boolean	isResolved() Suppressed:
Throwable	optProblem() Returns this broken ref's problem.
(package private) Ref	resolutionRef() Returns this.
Ref	sendAll(String verb, Object[] args) Suppressed: Use E.sendAll(obj, verb, args) rather than obj.sendAll(verb, args).
Throwable	sendAllOnly(String verb, Object[] args) Suppressed: Use E.sendAllOnly(obj, verb, args) rather than obj.sendAllOnly(verb, args).
(package private) void	setTarget(Ref newTarget) Used by a resolvers to change the target.
String	state() Returns BROKEN.

Methods inherited from class org.erights.e.elib.ref.Ref

broken, disconnected, getAllegedType, getOptProxyHandler, GetRefMaker, ignore, isBroken, isDeepFrozen, isDeepPassByCopy, isEventual, isFar, isNear, isPassByProxy, isPBC, isPersistent, isResolved, isSameEver, isSelfish, isSelfless, isSettled, makeBufferingPromise, makeSwitchablePromise, optBroken, optProblem, optSealedDispatch, optSealedDispatch, optShorten, promise, resolution, resolution, respondsTo, sendMsg, state, toCallable, toRef, toString, whenBroken, whenBrokenOnly, whenResolved, whenResolvedOnly

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

myProblem

private final Throwable myProblem

myIdentity

final Object myIdentity

Constructor Detail

DisconnectedRef

DisconnectedRef(Throwable problem,
                Object identity)

Makes a Ref that will never deliver messages to any object because of problem, but which is considered the same() as a particular object.

Iff two [Broken]FarRefs have the same() identity, then they are considered the same().

identity must itself be an honorary Selfless object.

Method Detail

equals

public boolean equals(Object other)

As an HONORARY Selfless object, my .equals() and .hashCode() determine sameness.

NOTE: Uses myIdentity's .equals(), which is safe, as myIdentity must be an honorary Selfless object.

Overrides:

equals in class Object

Parameters:

other - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

See Also:

Object.hashCode(), java.util.Hashtable

hashCode

public int hashCode()

As an HONORARY Selfless object, my .equals() and .hashCode() determine sameness. NOTE: Uses myIdentity's .hashCode(), which is safe, as myIdentity must be an honorary Selfless object.

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

java.lang.Object#equals(java.lang.Object), java.util.Hashtable

optProblem

public Throwable optProblem()

Returns this broken ref's problem.

All implementations of optProblem/0 must be thread safe, in order for Ref.state/0 to be thread safe.

Specified by:

optProblem in class Ref

Returns:

our problem

See Also:

Ref.optProblem(Object)

resolutionRef

Ref resolutionRef()

Returns this.

All implementations of resolutionRef/0 must be thread safe, in order for Ref.resolution/0 to be thread safe.

Specified by:

resolutionRef in class Ref

Returns:

this.

state

public String state()

Returns BROKEN.

All implementations of state/0 must be thread safe, in order for Ref.isNear/1 to be thread safe.

Overrides:

state in class Ref

Returns:

BROKEN

See Also:

Ref.state(Object)

doBreakage

private Throwable doBreakage(String verb,
                             Object[] args)

Should be called only if the state is already BROKEN.

Takes care of __whenMoreResolved(reactor) and __whenBroken(reactor). If you know verb/args aren't one of these, you don't need to call doBreakage().

Returns:

Why wasn't a __whenMoreResolved/1 or __whenBroken/1 queued? It isn't queued if this vat or comm connection is shut down, in which case the returned problem explains why. If null is returned, then the message wasn't __whenMoreResolved/1 or __whenBroken/1, in which case there was nothing to queue, or it was one of these and it was queued, though it may still not arrive.

callAll

public Object callAll(String verb,
                      Object[] args)

This default implementation switches on state() and either synchronously forward the message, if we're NEAR, or complains.

Specified by:

callAll in interface Callable

Specified by:

callAll in class Ref

sendAll

public Ref sendAll(String verb,
                   Object[] args)

Description copied from class: Ref

Suppressed: Use E.sendAll(obj, verb, args) rather than obj.sendAll(verb, args).

Specified by:

sendAll in class Ref

sendAllOnly

public Throwable sendAllOnly(String verb,
                             Object[] args)

Description copied from class: Ref

Suppressed: Use E.sendAllOnly(obj, verb, args) rather than obj.sendAllOnly(verb, args).

Specified by:

sendAllOnly in class Ref

Returns:

Why wasn't this event queued? It isn't queued if this vat or comm connection is shut down, in which case the returned problem explains why. If null is returned, then the event was queued, though it may still not arrive.

isResolved

public boolean isResolved()

Description copied from class: Ref

Suppressed:

Specified by:

isResolved in class Ref

setTarget

void setTarget(Ref newTarget)

Description copied from class: Ref

Used by a resolvers to change the target. If newTarget is equivalent to this Ref, then this Ref becomes broken by a ViciousCycleException.

Specified by:

setTarget in class Ref

commit

void commit()

Description copied from class: Ref

Used by a resolvers to turn off switchability, and thereby make this Ref equivalent to its current target.

If the current target is already equivalent to this Ref, then this Ref becomes broken by a ViciousCycleException.

Specified by:

commit in class Ref