=head1 NAME

Event::generic - generic event handling

=head1 SYNOPSIS

 use Event::generic;

 $source = Event::generic::Source->new;

 $w = Event->generic(source => $source, ...);
 $w = $source->watch(...);

 $source = $w->source;
 $w->source($source);

 $source->event;
 $source->event($data);

 $data = $event->data;

=head1 DESCRIPTION

This module provides a watcher type within the C<Event> framework.
You must understand the architecture of the C<Event> system in order to
understand this document.

This module provides a system of reified event sources and watchers
watching those sources.  Events are generated solely by a method on the
event source object.  The events may carry arbitrary data to the event
handler callbacks.  This module is intended for situations where the
events of interest are best determined by Perl code.

=head1 CLASSES

=over

=item Event::generic::Source

A reified event source.

=item Event::generic

A watcher that can watch C<Event::generic::Source> event sources.

=item Event::Event::Dataful

A (target) event that can carry arbitrary data.

=back

=head1 EVENT SOURCE CLASS

=head2 Constructor

=over

=item Event::generic::Source->new

Creates and returns a new event source.

=back

=head2 Methods

=over

=item $source->event

=item $source->event(DATA)

The invocation of this method is a source event for watchers of the
event source.  When this method is called, each active watcher of the
event source generates a target event.  The I<DATA>, if supplied, is
copied into the target event objects, from which it can be retrieved
using the C<data()> method.

=item $source->watch(ATTR => VALUE, ...)

Generates and returns a new watcher, configured to watch this event
source.  The standard watcher attributes may be specified as arguments.
The watcher returned is an ordinary C<Event::generic>, and may be
reconfigured to watch a different event source.

=back

=head1 WATCHER CLASS

=head2 Type-specific attributes

=over

=item source => $source

The event source to watch.  This must be either an
C<Event::generic::Source> object or C<undef>.  When set to C<undef>,
no source is being watched, and the watcher cannot be started.

=back

=head1 EVENT CLASS

=head2 Type-specific methods

=over

=item $event->data

Returns the data associated with the event, which may be any scalar.
This is read-only, and is set by the event source.

=back

=head1 SEE ALSO

L<Event>
