JBZoo / Event

The EventEmitter is a simple pattern that allows you to create an object that emits events, and allow you to listen to those events.

Install

composer require jbzoo/event

Simple example

use JBZoo\Event\EventManager;

$eManager = new EventManager();

// Simple
$eManager->on('create', function () {
    echo "Something action";
});

// Just do it!
$eManager->trigger('create');

Set priority

By supplying a priority, you are ensured that subscribers handle in a specific order. The default priority is EventManager::MID. Anything below that will be triggered earlier, anything higher later. If there are two subscribers with the same priority, they will execute in an undefined, but deterministic order.

// Run it first
$eManager->on('create', function () {
    echo "Something high priority action";
}, EventManager::HIGH);

// Run it latest
$eManager->on('create', function () {
    echo "Something another action";
}, EventManager::LOW);

// Custom index
$eManager->on('create', function () {
    echo "Something action";
}, 42);

// Don't care...
$eManager->on('create', function () {
    echo "Something action";
});

Types of Callback

All default PHP callbacks are supported, so closures are not required.

$eManager->on('create', function(){ /* ... */ }); // Custom function
$eManager->on('create', 'myFunction');            // Custom function name
$eManager->on('create', ['myClass', 'myMethod']); // Static function
$eManager->on('create', [$object, 'Method']);     // Method of instance

Cancel queue of events

use JBZoo\Event\ExceptionStop;

$eManager->on('create', function () {
    throw new ExceptionStop('Some reason'); // Special exception for JBZoo/Event
});

$eManager->trigger('create'); // return 'Some reason' or TRUE if all events done

Passing arguments

Arguments can be passed as an array.

$eManager->on('create', function ($entityId) {
    echo "An entity with id ", $entityId, " just got created.\n";
});
$entityId = 5;
$eManager->trigger('create', [$entityId]);

Because you cannot really do anything with the return value of a listener, you can pass arguments by reference to communicate between listeners and back to the emitter.

$eManager->on('create', function ($entityId, &$warnings) {
    echo "An entity with id ", $entityId, " just got created.\n";
    $warnings[] = "Something bad may or may not have happened.\n";
});
$warnings = [];
$eManager->trigger('create', [$entityId, &$warnings]);

Namespaces

$eManager->on('item.*', function () {
    // item.init
    // item.save
    echo "Any actions with item";
});

$eManager->on('*.init', function () {
    // tag.init
    // item.init
    echo "Init any entity";
});

$eManager->on('*.save', function () {
    // tag.save
    // item.save
    echo "Saving any entity in system";
});

$eManager->on('*.save.after', function () {
    // tag.save.after
    // item.save.after
    echo "Any entity on after save";
});

$eManager->trigger('tag.init');
$eManager->trigger('tag.save.before');
$eManager->trigger('tag.save');
$eManager->trigger('tag.save.after');

$eManager->trigger('item.init');
$eManager->trigger('item.save.before');
$eManager->trigger('item.save');
$eManager->trigger('item.save.after');

Summary benchmark info (execution time) PHP v7.4

All benchmark tests are executing without xdebug and with a huge random array and 100.000 iterations.

Benchmark tests based on the tool phpbench/phpbench. See details here.

Please, pay attention - 1μs = 1/1.000.000 of second!

benchmark: ManyCallbacks

subject	groups	its	revs	mean	stdev	rstdev	mem_real	diff
benchOneUndefined	undefined	10	100000	0.65μs	0.01μs	1.00%	6,291,456b	1.00x
benchOneWithStarBegin	*.bar	10	100000	0.67μs	0.01μs	1.44%	6,291,456b	1.04x
benchOneWithAllStars	.	10	100000	0.68μs	0.03μs	4.18%	6,291,456b	1.04x
benchOneWithStarEnd	foo.*	10	100000	0.68μs	0.01μs	1.24%	6,291,456b	1.04x
benchOneNested	foo.bar	10	100000	43.23μs	0.46μs	1.07%	6,291,456b	66.56x
benchOneSimple	foo	10	100000	45.07μs	2.63μs	5.83%	6,291,456b	69.39x

benchmark: ManyCallbacksWithPriority

subject	groups	its	revs	mean	stdev	rstdev	mem_real	diff
benchOneUndefined	undefined	10	100000	0.65μs	0.01μs	1.35%	6,291,456b	1.00x
benchOneNestedStarAll	.	10	100000	0.67μs	0.01μs	1.34%	6,291,456b	1.03x
benchOneWithStarBegin	*.bar	10	100000	0.67μs	0.01μs	1.10%	6,291,456b	1.04x
benchOneWithStarEnd	foo.*	10	100000	0.68μs	0.01μs	1.13%	6,291,456b	1.05x
benchOneSimple	foo	10	100000	4.54μs	0.02μs	0.35%	6,291,456b	7.03x
benchOneNested	foo.bar	10	100000	4.58μs	0.04μs	0.81%	6,291,456b	7.10x

benchmark: OneCallback

subject	groups	its	revs	mean	stdev	rstdev	mem_real	diff
benchOneWithStarBegin	*.bar	10	100000	0.69μs	0.03μs	4.00%	6,291,456b	1.00x
benchOneWithStarEnd	foo.*	10	100000	0.70μs	0.03μs	4.22%	6,291,456b	1.00x
benchOneNestedStarAll	.	10	100000	0.70μs	0.04μs	6.02%	6,291,456b	1.01x
benchOneUndefined	undefined	10	100000	0.71μs	0.05μs	7.44%	6,291,456b	1.02x
benchOneSimple	foo	10	100000	1.18μs	0.03μs	2.27%	6,291,456b	1.70x
benchOneNested	foo.bar	10	100000	1.25μs	0.03μs	2.46%	6,291,456b	1.81x

benchmark: Random

subject	groups	its	revs	mean	stdev	rstdev	mem_real	diff
benchOneSimple	random.*.triggers	10	100000	4.29μs	0.33μs	7.69%	6,291,456b	1.00x

Unit tests and check code style

make update
make test-all

License

MIT