Added more event and listener interface definitions.
diff --git a/net/api/src/main/java/org/onlab/onos/net/host/HostEvent.java b/net/api/src/main/java/org/onlab/onos/net/host/HostEvent.java
new file mode 100644
index 0000000..b06e8b8
--- /dev/null
+++ b/net/api/src/main/java/org/onlab/onos/net/host/HostEvent.java
@@ -0,0 +1,53 @@
+package org.onlab.onos.net.host;
+
+import org.onlab.onos.event.AbstractEvent;
+import org.onlab.onos.net.Host;
+
+/**
+ * Describes end-station host event.
+ */
+public class HostEvent extends AbstractEvent<HostEvent.Type, Host> {
+
+ /**
+ * Type of host events.
+ */
+ public enum Type {
+ /**
+ * Signifies that a new host has been detected.
+ */
+ HOST_ADDED,
+
+ /**
+ * Signifies that a host has been removed.
+ */
+ HOST_REMOVED,
+
+ /**
+ * Signifies that a host location has changed.
+ */
+ HOST_MOVED
+ }
+
+ /**
+ * Creates an event of a given type and for the specified host and the
+ * current time.
+ *
+ * @param type host event type
+ * @param host event host subject
+ */
+ public HostEvent(Type type, Host host) {
+ super(type, host);
+ }
+
+ /**
+ * Creates an event of a given type and for the specified host and time.
+ *
+ * @param type host event type
+ * @param host event host subject
+ * @param time occurrence time
+ */
+ public HostEvent(Type type, Host host, long time) {
+ super(type, host, time);
+ }
+
+}