DisconnectedRef (ELib API)

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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