SYNOPSIS

package Cat;
use Mojo::Base 'Mojo::EventEmitter';
# Emit events
sub poke {
my $self = shift;
$self->emit(roar => 3);
}
package main;
# Subscribe to events
my $tiger = Cat->new;
$tiger->on(roar => sub {
my ($tiger, $times) = @_;
say 'RAWR!' for 1 .. $times;
});
$tiger->poke;

DESCRIPTION

Mojo::EventEmitter is a simple base class for event emitting objects.

EVENTS

Mojo::EventEmitter can emit the following events.

error

  $e->on(error => sub {
    my ($e, $err) = @_;
    ...
  });

This is a special event for errors, it will not be emitted directly by this class but is fatal if unhandled.

  $e->on(error => sub {
    my ($e, $err) = @_;
    say "This looks bad: $err";
  });

METHODS

Mojo::EventEmitter inherits all methods from Mojo::Base and implements the following new ones.

catch

  $e = $e->catch(sub {...});

Subscribe to ``error'' event.

  # Longer version
  $e->on(error => sub {...});

emit

  $e = $e->emit('foo');
  $e = $e->emit('foo', 123);

Emit event.

has_subscribers

  my $bool = $e->has_subscribers('foo');

Check if event has subscribers.

on

  my $cb = $e->on(foo => sub {...});

Subscribe to event.

  $e->on(foo => sub {
    my ($e, @args) = @_;
    ...
  });

once

  my $cb = $e->once(foo => sub {...});

Subscribe to event and unsubscribe again after it has been emitted once.

  $e->once(foo => sub {
    my ($e, @args) = @_;
    ...
  });

subscribers

  my $subscribers = $e->subscribers('foo');

All subscribers for event.

  # Unsubscribe last subscriber
  $e->unsubscribe(foo => $e->subscribers('foo')->[-1]);
  # Change order of subscribers
  @{$e->subscribers('foo')} = reverse @{$e->subscribers('foo')};

unsubscribe

  $e = $e->unsubscribe('foo');
  $e = $e->unsubscribe(foo => $cb);

Unsubscribe from event.

DEBUGGING

You can set the "MOJO_EVENTEMITTER_DEBUG" environment variable to get some advanced diagnostics information printed to "STDERR".

  MOJO_EVENTEMITTER_DEBUG=1