Module dispatcher

Connect receiver to sender for signal

receiver -- a callable Python object which is to receive
    messages/signals/events.  Receivers must be hashable
    objects.

    if weak is True, then receiver must be weak-referencable
    (more precisely saferef.safeRef() must be able to create
    a reference to the receiver).

    Receivers are fairly flexible in their specification,
    as the machinery in the robustApply module takes care
    of most of the details regarding figuring out appropriate
    subsets of the sent arguments to apply to a given
    receiver.

    Note:
        if receiver is itself a weak reference (a callable),
        it will be de-referenced by the system's machinery,
        so *generally* weak references are not suitable as
        receivers, though some use might be found for the
        facility whereby a higher-level library passes in
        pre-weakrefed receiver references.

signal -- the signal to which the receiver should respond

    if Any, receiver will receive any signal from the
    indicated sender (which might also be Any, but is not
    necessarily Any).
    
    Otherwise must be a hashable Python object other than
    None (DispatcherError raised on None).
    
sender -- the sender to which the receiver should respond

    if Any, receiver will receive the indicated signals
    from any sender.
    
    if Anonymous, receiver will only receive indicated
    signals from send/sendExact which do not specify a
    sender, or specify Anonymous explicitly as the sender.

    Otherwise can be any python object.
    
weak -- whether to use weak references to the receiver
    By default, the module will attempt to use weak
    references to the receiver objects.  If this parameter
    is false, then strong references will be used.

returns None, may raise DispatcherTypeError

Disconnect receiver from sender for signal

receiver -- the registered receiver to disconnect
signal -- the registered signal to disconnect
sender -- the registered sender to disconnect
weak -- the weakref state to disconnect

disconnect reverses the process of connect,
the semantics for the individual elements are
logically equivalent to a tuple of
(receiver, signal, sender, weak) used as a key
to be deleted from the internal routing tables.
(The actual process is slightly more complex
but the semantics are basically the same).

Note:
    Using disconnect is not required to cleanup
    routing when an object is deleted, the framework
    will remove routes for deleted objects
    automatically.  It's only necessary to disconnect
    if you want to stop routing to a live object.
    
returns None, may raise DispatcherTypeError or
    DispatcherKeyError

Get list of receivers from global tables

This utility function allows you to retrieve the
raw list of receivers from the connections table
for the given sender and signal pair.

Note:
    there is no guarantee that this is the actual list
    stored in the connections table, so the value
    should be treated as a simple iterable/truth value
    rather than, for instance a list to which you
    might append new records.

Normally you would use liveReceivers( getReceivers( ...))
to retrieve the actual receiver objects as an iterable
object.

Filter sequence of receivers to get resolved, live receivers

This is a generator which will iterate over the passed sequence, checking for weak references and resolving them, then returning all live receivers.

Get list of all receivers from global tables

This gets all dereferenced receivers which should receive the given signal from sender, each receiver should be produced only once by the resulting generator

Send signal from sender to all connected receivers.

signal -- (hashable) signal value, see connect for details

sender -- the sender of the signal

    if Any, only receivers registered for Any will receive
    the message.

    if Anonymous, only receivers registered to receive
    messages from Anonymous or Any will receive the message

    Otherwise can be any python object (normally one
    registered with a connect if you actually want
    something to occur).

arguments -- positional arguments which will be passed to
    *all* receivers. Note that this may raise TypeErrors
    if the receivers do not allow the particular arguments.
    Note also that arguments are applied before named
    arguments, so they should be used with care.

named -- named arguments which will be filtered according
    to the parameters of the receivers to only provide those
    acceptable to the receiver.

Return a list of tuple pairs [(receiver, response), ... ]

if any receiver raises an error, the error propagates back
through send, terminating the dispatch loop, so it is quite
possible to not have all receivers called if a raises an
error.

Send signal only to those receivers registered for exact message

sendExact allows for avoiding Any/Anonymous registered handlers, sending only to those receivers explicitly registered for a particular signal on a particular sender.

__cvsid__

Value:

"$Id: dispatcher.py,v 1.9 2005/09/17 04:55:57 mcfletch Exp $"