cleanup usage of event dispatcher with CacheInvalidator

Author: dbu

CHANGELOG.md

@@ -1,6 +1,12 @@
 Changelog
 =========
 
+* **2015-02-11** It is no longer possible to change the event dispatcher of the
+  CacheInvalidator once its instantiated. If you need a custom dispatcher, set it
+  right after creating the invalidator instance. Deprecated CacheInvalidator::addSubscriber
+  in favor of either using the event dispatcher instance you inject or do
+  getEventDispatcher()->addSubscriber($subscriber)
+
 1.2.0
 -----
 

doc/cache-invalidator.rst

@@ -197,7 +197,7 @@ Then add the logger as a subscriber to the cache invalidator::
     use FOS\HttpCache\EventListener\LogSubscriber;
 
     $subscriber = new LogSubscriber($monolog);
-    $cacheInvalidator->addSubscriber($subscriber);
+    $cacheInvalidator->getEventDispatcher()->addSubscriber($subscriber);
 
 Now, if you flush the invalidator, errors will be logged::
 

src/CacheInvalidator.php

@@ -118,6 +118,11 @@ public function supports($operation)
      */
     public function setEventDispatcher(EventDispatcherInterface $eventDispatcher)
     {
+        if ($this->eventDispatcher) {
+            // if you want to set a custom event dispatcher, do so right after instantiating
+            // the invalidator.
+            throw new \Exception('You may not change the event dispatcher once it is set.');
+        }
         $this->eventDispatcher = $eventDispatcher;
     }
 
@@ -141,6 +146,8 @@ public function getEventDispatcher()
      * @param EventSubscriberInterface $subscriber
      *
      * @return $this
+     *
+     * @deprecated Use getEventDispatcher()->addSubscriber($subscriber) instead.
      */
     public function addSubscriber(EventSubscriberInterface $subscriber)
     {

tests/Unit/CacheInvalidatorTest.php

@@ -209,7 +209,7 @@ public function testProxyClientExceptionsAreLogged()
             ->with('critical', '403 error response "Forbidden" from caching proxy at http://127.0.0.1', array('exception' => $responseException))
             ->getMock();
 
-        $cacheInvalidator->addSubscriber(new LogSubscriber($logger));
+        $cacheInvalidator->getEventDispatcher()->addSubscriber(new LogSubscriber($logger));
 
         $cacheInvalidator
             ->flush()