NAME
    POE::API::Hooks - Implement lightweight hooks into POE

SYNOPSIS
      use POE;
      use POE::API::Hooks;

      POE::API::Hooks->add(
          before_event_dispatch  => \&do_something,
          after_event_dispatch   => \&do_something,
          before_session_create  => \&do_something,
          after_session_create   => \&do_something,
          before_event_enqueue   => \&do_something,
          after_event_enqueue    => \&do_something,
      );

      # ... carry on with life as normal ...

DISCUSSION
    This module adds lightweight hooks into the inner workings of POE.
    Currently, one can add hooks into POE that get called before/after an
    event is dispatched, before/after a Session is created, and/or
    before/after an event is enqueued. These callbacks receive the exact
    same argument list as their Kernel/Session counterpart. For event
    dispatch related callbacks, see "_dispatch_event" and "_data_ev_enqueue"
    in POE::Kernel. For session related callbacks, see "create" in
    POE::Session.

WARNING
    This interface is designed for advanced users. Wrapping any of the
    available POE internals is a potentially dangerous operation. Please
    read the POE documentation and source code carefully before attempting
    an override of this nature.

METHODS
  add
      POE::API::Hooks->add(
          before_event_dispatch  => \&do_something,
          after_event_dispatch   => \&do_something,

          before_session_create  => \&do_something,
          after_session_create   => \&do_something,

          before_event_enqueue   => \&do_something,
          after_event_enqueue    => \&do_something,
      );

    "add" is the only public method of this class. The method installs the
    requested hooks. The list of options above contains all possible hooks.
    No hook is required so the user may set only one hook if they desire.

    The callback provided for each hook will be called, obviously, when that
    state occurs. "before_event_dispatch" will be called just before event
    dispatch, for instance. These callbacks are passed whatever arguments
    are provided to the wrapped subroutine. For instance, if a
    "before_session_create" callback is registered and a user calls
    "POE::Session->create('POE')", the registered callback will receive
    "('POE::Session', 'POE')" in @_.

BUGS
    When "$_[KERNEL]->call($_[SESSION], "event")" is used, _event_dispatch
    is bypassed. This is an optimization, not a bug, but it will cause the
    event_dispatch hook to be bypassed under this condition. Someone relying
    on the event_dispatch hook may call this a bug.

AUTHOR
    Matt Cashner (sungo@pobox.com)

LICENSE
    Copyright (c) 2004, 2008 Matt Cashner. All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:

    *   Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

    *   Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.

    *   Neither the name of Matt Cashner nor the names of its contributors
        may be used to endorse or promote products derived from this
        software without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
    IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
    TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
    PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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