Event history service and CLI
- Tool created while debugging ONOS-3509
Usage Example: (See recent Mastership and Device events)
onos> events -m -d
Change-Id: I87aceaf8fe61732a61c2d1e39399d0f10a729b54
diff --git a/core/api/src/main/java/org/onosproject/event/ListenerTracker.java b/core/api/src/main/java/org/onosproject/event/ListenerTracker.java
new file mode 100644
index 0000000..aa42460
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/event/ListenerTracker.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * 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 org.onosproject.event;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.annotation.concurrent.NotThreadSafe;
+
+import org.apache.commons.lang3.tuple.Pair;
+
+import com.google.common.annotations.Beta;
+import com.google.common.collect.Lists;
+
+/**
+ * Utility to keeps track of registered Listeners.
+ * <p>
+ * Usage Example:
+ * <pre>
+ * <code>
+ private ListenerTracker listeners;
+
+ {@code @Activate}
+ protected void activate() {
+ listeners = new ListenerTracker();
+ listeners.addListener(mastershipService, new InternalMastershipListener())
+ .addListener(deviceService, new InternalDeviceListener())
+ .addListener(linkService, new InternalLinkListener())
+ .addListener(topologyService, new InternalTopologyListener())
+ .addListener(hostService, new InternalHostListener());
+ }
+
+ {@code @Deactivate}
+ protected void deactivate() {
+ listeners.removeListeners();
+ }
+ * </code>
+ * </pre>
+ */
+@Beta
+@NotThreadSafe
+public class ListenerTracker {
+
+ @SuppressWarnings("rawtypes")
+ private List<Pair<ListenerService, EventListener>> listeners = new ArrayList<>();
+
+ /**
+ * Adds {@link EventListener} to specified {@link ListenerService}.
+ *
+ * @param service {@link ListenerService}
+ * @param listener {@link EventListener}
+ * @return self
+ */
+ public <E extends Event<?, ?>, L extends EventListener<E>>
+ ListenerTracker addListener(ListenerService<E, L> service, L listener) {
+ service.addListener(listener);
+ listeners.add(Pair.of(service, listener));
+ return this;
+ }
+
+ /**
+ * Removes all listeners in reverse order they have been registered.
+ */
+ public void removeListeners() {
+ Lists.reverse(listeners)
+ .forEach(r -> r.getLeft().removeListener(r.getRight()));
+ listeners.clear();
+ }
+}