feat(event): Add initial implementation of the internal event bus

admin/api/src/main/java/io/gravitee/admin/api/resources/ApiResource.java

@@ -34,7 +34,7 @@
 @Singleton
 @Produces(MediaType.APPLICATION_JSON)
 @Path("/apis")
-// TODO handle messages responses
+// TODO doNext messages responses
 public class ApiResource extends AbstractResource {
 
     @GET

gateway/api/src/main/java/io/gravitee/gateway/api/Policy.java

@@ -20,9 +20,9 @@
  */
 public interface Policy {
 
-    void onRequest(final Request request, final Response response, final PolicyHandler handler);
+    void onRequest(final Request request, final Response response, final PolicyChain handler);
 
-    void onResponse(final Request request, final Response response, final PolicyHandler handler);
+    void onResponse(final Request request, final Response response, final PolicyChain handler);
 
     String name();
 }

gateway/api/src/main/java/io/gravitee/gateway/api/PolicyHandler.java → gateway/api/src/main/java/io/gravitee/gateway/api/PolicyChain.java

@@ -19,9 +19,7 @@
  *
  * @author David BRASSELY (brasseld at gmail.com)
  */
-public interface PolicyHandler {
+public interface PolicyChain {
 
-    void handle(Request request, Response response);
-
-    void fail(Request request, Response response, Throwable throwable);
+    void doNext(Request request, Response response);
 }

gateway/api/src/main/java/io/gravitee/gateway/api/PolicyResult.java

@@ -0,0 +1,22 @@
+/**
+ * Copyright (C) 2015 The Gravitee team (http://gravitee.io)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.gravitee.gateway.api;
+
+/**
+ * @author David BRASSELY (brasseld at gmail.com)
+ */
+public interface PolicyResult {
+}

gateway/core/src/main/java/io/gravitee/gateway/core/Reactor.java

@@ -23,7 +23,7 @@
  *
  * @author David BRASSELY (brasseld at gmail.com)
  */
-public interface Reactor {
+public interface Reactor<T> {
 
-	Observable<Response> process(Request request);
+	T process(Request request);
 }

gateway/core/src/main/java/io/gravitee/gateway/core/event/Event.java

@@ -0,0 +1,26 @@
+/**
+ * Copyright (C) 2015 The Gravitee team (http://gravitee.io)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.gravitee.gateway.core.event;
+
+/**
+ * @author David BRASSELY (brasseld at gmail.com)
+ */
+public interface Event<T extends Enum, S> {
+
+  S content();
+
+  T type();
+}

gateway/core/src/main/java/io/gravitee/gateway/core/event/EventListener.java

@@ -0,0 +1,24 @@
+/**
+ * Copyright (C) 2015 The Gravitee team (http://gravitee.io)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.gravitee.gateway.core.event;
+
+/**
+ * @author David BRASSELY (brasseld at gmail.com)
+ */
+public interface EventListener<T extends Enum, S> {
+
+  void onEvent(Event<T, S> event);
+}

gateway/core/src/main/java/io/gravitee/gateway/core/policy/RequestPolicyHandler.java → gateway/core/src/main/java/io/gravitee/gateway/core/event/EventManager.java

@@ -13,28 +13,18 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package io.gravitee.gateway.core.policy;
-
-import io.gravitee.gateway.api.Policy;
-import io.gravitee.gateway.api.Request;
-import io.gravitee.gateway.api.Response;
-
-import java.util.Set;
+package io.gravitee.gateway.core.event;
 
 /**
  * @author David BRASSELY (brasseld at gmail.com)
  */
-public class RequestPolicyHandler extends AbstractPolicyHandler {
+public interface EventManager {
+
+  void publishEvent(Enum type, Object content);
+
+  void publishEvent(Event event);
 
-    public RequestPolicyHandler(Set<Policy> policies) {
-        super(policies);
-    }
+  <T extends Enum> void subscribeForEvents(EventListener<T, ?> eventListener, Class<T> events);
 
-    @Override
-    public void handle(Request request, Response response) {
-        if (iterator().hasNext()) {
-            Policy first = iterator().next();
-            first.onRequest(request, response, this);
-        }
-    }
+  <T extends Enum> void subscribeForEvents(EventListener<T, ?> eventListener, T... events);
 }

gateway/core/src/main/java/io/gravitee/gateway/core/event/impl/EventManagerImpl.java

@@ -0,0 +1,123 @@
+/**
+ * Copyright (C) 2015 The Gravitee team (http://gravitee.io)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.gravitee.gateway.core.event.impl;
+
+import io.gravitee.gateway.core.event.Event;
+import io.gravitee.gateway.core.event.EventListener;
+import io.gravitee.gateway.core.event.EventManager;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.*;
+
+/**
+ * @author David BRASSELY (brasseld at gmail.com)
+ */
+public class EventManagerImpl implements EventManager {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(EventManagerImpl.class);
+
+  private Map<ComparableEventType, Set<EventListenerWrapper>> listenersMap = new TreeMap();
+
+  public void publishEvent(Enum type, Object content) {
+    this.publishEvent(new SimpleEvent(type, content));
+  }
+
+  public void publishEvent(Event event) {
+    LOGGER.debug("Publish event {} - {}", event.type(), event.content());
+
+    Set<EventListenerWrapper> listeners = getEventListeners(event.type().getClass());
+    for(EventListenerWrapper listener : listeners) {
+      listener.eventListener().onEvent(event);
+    }
+  }
+
+  public <T extends Enum> void subscribeForEvents(EventListener<T, ?> eventListener, T... events) {
+    for( T event : events) {
+      addEventListener(eventListener, (Class<T>) event.getClass(), Arrays.asList(events));
+    }
+  }
+
+  public <T extends Enum> void subscribeForEvents(EventListener<T, ?> eventListener, Class<T> events) {
+    addEventListener(eventListener, events, EnumSet.allOf(events));
+  }
+
+  private <T extends Enum> void addEventListener(EventListener<T, ?> eventListener, Class<T> enumClass, Collection<T> events) {
+    LOGGER.info("Register new listener {} for event type {}", eventListener.getClass().getSimpleName(), enumClass);
+
+    Set<EventListenerWrapper> listeners = getEventListeners(enumClass);
+    listeners.add(new EventListenerWrapper(eventListener, events));
+  }
+
+  private <T extends Enum> Set<EventListenerWrapper> getEventListeners(Class<T> eventType) {
+    Set<EventListenerWrapper> listeners = this.listenersMap.get(new ComparableEventType(eventType));
+
+    if (listeners == null) {
+      listeners = new HashSet();
+      this.listenersMap.put(new ComparableEventType(eventType), listeners);
+    }
+
+    return listeners;
+  }
+
+  private class EventListenerWrapper<T extends Enum> {
+
+    private final EventListener<T, ?> eventListener;
+    private final Set<T> events;
+
+    public EventListenerWrapper(EventListener<T, ?> eventListener, Collection<T> events) {
+      this.eventListener = eventListener;
+      this.events = new HashSet(events);
+    }
+
+    public EventListener<T, ?> eventListener() {
+      return eventListener;
+    }
+
+    public Set<T> events() {
+      return events;
+    }
+  }
+
+  private class ComparableEventType<T> implements Comparable<ComparableEventType<T>> {
+
+    private static final int HASH = 7 * 89;
+    private final Class<? extends T> wrappedClass;
+
+    public ComparableEventType(Class<? extends T> wrappedClass) {
+      this.wrappedClass = wrappedClass;
+    }
+
+    @Override
+    public int compareTo(ComparableEventType<T> o) {
+      return wrappedClass.getCanonicalName().compareTo(o.wrappedClass.getCanonicalName());
+    }
+
+    @Override
+    public int hashCode() {
+      return HASH + (this.wrappedClass != null ? this.wrappedClass.hashCode() : 0);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (!(o instanceof ComparableEventType)) {
+        return false;
+      }
+
+      return compareTo((ComparableEventType<T>) o) == 0;
+    }
+  }
+}

gateway/core/src/main/java/io/gravitee/gateway/core/policy/ResponsePolicyHandler.java → gateway/core/src/main/java/io/gravitee/gateway/core/event/impl/SimpleEvent.java

@@ -13,28 +13,28 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package io.gravitee.gateway.core.policy;
+package io.gravitee.gateway.core.event.impl;
 
-import io.gravitee.gateway.api.Policy;
-import io.gravitee.gateway.api.Request;
-import io.gravitee.gateway.api.Response;
-
-import java.util.Set;
+import io.gravitee.gateway.core.event.Event;
 
 /**
  * @author David BRASSELY (brasseld at gmail.com)
  */
-public class ResponsePolicyHandler extends AbstractPolicyHandler {
+public class SimpleEvent<T extends Enum, S> implements Event<T, S> {
+
+  private final T type;
+  private final S content;
+
+  public SimpleEvent(T type, S content) {
+    this.type = type;
+    this.content = content;
+  }
 
-    public ResponsePolicyHandler(Set<Policy> policies) {
-        super(policies);
-    }
+  @Override public S content() {
+    return this.content;
+  }
 
-    @Override
-    public void handle(Request request, Response response) {
-        if (iterator().hasNext()) {
-            Policy first = iterator().next();
-            first.onResponse(request, response, this);
-        }
-    }
+  @Override public T type() {
+    return this.type;
+  }
 }

gateway/core/src/main/java/io/gravitee/gateway/core/handler/ContextHandler.java

@@ -0,0 +1,15 @@
+package io.gravitee.gateway.core.handler;
+
+import io.gravitee.gateway.api.Request;
+import io.gravitee.gateway.api.Response;
+
+/**
+ * @author David BRASSELY (brasseld at gmail.com)
+ */
+public class ContextHandler implements Handler {
+
+    @Override
+    public void handle(Request request, Response response) {
+
+    }
+}

gateway/core/src/main/java/io/gravitee/gateway/core/handler/Handler.java

@@ -0,0 +1,12 @@
+package io.gravitee.gateway.core.handler;
+
+import io.gravitee.gateway.api.Request;
+import io.gravitee.gateway.api.Response;
+
+/**
+ * @author David BRASSELY (brasseld at gmail.com)
+ */
+public interface Handler {
+
+    void handle(Request request, Response response);
+}

gateway/core/src/main/java/io/gravitee/gateway/core/policy/AbstractPolicyHandler.java → gateway/core/src/main/java/io/gravitee/gateway/core/policy/AbstractPolicyChain.java

@@ -16,9 +16,7 @@
 package io.gravitee.gateway.core.policy;
 
 import io.gravitee.gateway.api.Policy;
-import io.gravitee.gateway.api.PolicyHandler;
-import io.gravitee.gateway.api.Request;
-import io.gravitee.gateway.api.Response;
+import io.gravitee.gateway.api.PolicyChain;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -28,23 +26,18 @@
 /**
  * @author David BRASSELY (brasseld at gmail.com)
  */
-public abstract class AbstractPolicyHandler implements PolicyHandler {
+public abstract class AbstractPolicyChain implements PolicyChain {
 
     private final Logger LOGGER = LoggerFactory.getLogger(getClass());
 
     private Set<Policy> policies;
     private Iterator<Policy> policyIterator;
 
-    protected AbstractPolicyHandler(final Set<Policy> policies) {
+    protected AbstractPolicyChain(final Set<Policy> policies) {
         this.policies = policies;
         this.policyIterator = policies.iterator();
     }
 
-    @Override
-    public void fail(Request request, Response response, Throwable throwable) {
-        LOGGER.info("Exit policy chain...");
-    }
-
     public Set<Policy> getPolicies() {
         return this.policies;
     }