org.erights.e.elib.ref
Class WhenBrokenReactor

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

All Implemented Interfaces:

DeadManSwitch, Marker, OneArgFunc, PassByProxy

class WhenBrokenReactor

extends Object

implements DeadManSwitch, OneArgFunc, PassByProxy

Used to implement Ref.whenBroken(Object, OneArgFunc).

Wraps a 'done' function (the second argument of whenBroken), so that the done function will eventually be invoked with the original reference exactly once under the following conditions:

• The original reference is broken

This object is woken up by __reactToLostClient and the response to __whenBroken, but in both cases it ignores the argument and treats the message just as a wakeup call.

Author:

Mark S. Miller, Terry Stanley

See Also:

WhenResolvedReactor

Field Summary

private Resolver	myOptResolver
private OneArgFunc	myOptWrapped
private Object	myRef

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

HONORARY, HONORED_NAMES

Constructor Summary

WhenBrokenReactor(OneArgFunc wrapped, Object ref, Resolver optResolver)
Should ref become broken, invoke wrapped, and resolve optResolver (if not null) to its outcome.

Method Summary

void	__reactToLostClient(Throwable problem) Just like run/1, this is treated merely as a wakeup call to check myRef.
Object	run(Object ignored) Causes us to wakeup and check if myRef is broken.

Methods inherited from class java.lang.Object

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

Field Detail

myOptWrapped

private OneArgFunc myOptWrapped

myRef

private Object myRef

myOptResolver

private Resolver myOptResolver

Constructor Detail

WhenBrokenReactor

public WhenBrokenReactor(OneArgFunc wrapped,
                         Object ref,
                         Resolver optResolver)

Should ref become broken, invoke wrapped, and resolve optResolver (if not null) to its outcome.

Assumes a first __whenBroken will be sent with this WhenBrokenReactor as argument.

Method Detail

run

public Object run(Object ignored)

Causes us to wakeup and check if myRef is broken.

If myRef is broken, then invoke myOptWrapped once (resolving myOptResolver to the outcome), and remember not to invoke it again (by forgetting it). Also forget myRef and myOptResolver, since we won't need them again. Further invocations silently return null rather than complaining.

If myRef is not resolved, then send a new

     myRef <- __whenMoreResolved(this)
 

message whose response should wake me up again. If myRef is resolved but not broken, then be clever.

Specified by:

run in interface OneArgFunc

Returns:

Always returns null, irrespective of what myOptWrapped.run(arg) returns.

__reactToLostClient

public void __reactToLostClient(Throwable problem)

Just like run/1, this is treated merely as a wakeup call to check myRef.

Specified by:

__reactToLostClient in interface DeadManSwitch

See Also:

org.erights.e.elib.prim.MirandaMethods#__reactToLostClient