Add an option to specify identity for subscriber; Add an option to pu…

…blish event only for specified targets

dew-common/src/dev/shiza/dew/event/EventBus.java

@@ -12,5 +12,5 @@ static EventBus create(final SubscriptionFacade subscriptionFacade) {
 
   void subscribe(final Subscriber subscriber) throws SubscribingException;
 
-  void publish(final Event event) throws EventPublishingException;
+  void publish(final Event event, final String... targets) throws EventPublishingException;
 }

dew-common/src/dev/shiza/dew/event/EventBusImpl.java

@@ -4,6 +4,7 @@
 import dev.shiza.dew.subscription.Subscription;
 import dev.shiza.dew.subscription.SubscriptionFacade;
 import java.lang.invoke.MethodHandle;
+import java.util.Arrays;
 import java.util.Set;
 
 final class EventBusImpl implements EventBus {
@@ -20,16 +21,21 @@ public void subscribe(final Subscriber subscriber) {
   }
 
   @Override
-  public void publish(final Event event) {
+  public void publish(final Event event, final String... targets) {
     final Set<Subscription> subscriptions =
         subscriptionFacade.getSubscriptionsByEventType(event.getClass());
     for (final Subscription subscription : subscriptions) {
-      notifySubscription(subscription, event);
+      notifySubscription(subscription, event, targets);
     }
   }
 
-  private void notifySubscription(final Subscription subscription, final Event event) {
+  private void notifySubscription(
+      final Subscription subscription, final Event event, final String[] targets) {
     final Subscriber subscriber = subscription.subscriber();
+    if (hasSpecifiedTarget(targets) && isExcludedSubscription(subscriber, targets)) {
+      return;
+    }
+
     for (final MethodHandle invocation : subscription.invocations()) {
       notifySubscribedMethods(invocation, subscriber, event);
     }
@@ -45,4 +51,12 @@ private void notifySubscribedMethods(
           exception);
     }
   }
+
+  private boolean hasSpecifiedTarget(final String[] targets) {
+    return targets.length > 0;
+  }
+
+  private boolean isExcludedSubscription(final Subscriber subscriber, final String[] targets) {
+    return Arrays.stream(targets).noneMatch(identity -> subscriber.identity().equals(identity));
+  }
 }

dew-common/src/dev/shiza/dew/subscription/Subscriber.java

@@ -1,3 +1,8 @@
 package dev.shiza.dew.subscription;
 
-public interface Subscriber {}
+public interface Subscriber {
+
+  default String identity() {
+    return null;
+  }
+}