1 files changed, 40 insertions, 0 deletions

diff --git a/framework/src/onos/core/api/src/main/java/org/onosproject/net/host/HostEvent.java b/framework/src/onos/core/api/src/main/java/org/onosproject/net/host/HostEvent.java
index 98329df0..92824cf8 100644
--- a/framework/src/onos/core/api/src/main/java/org/onosproject/net/host/HostEvent.java
+++ b/framework/src/onos/core/api/src/main/java/org/onosproject/net/host/HostEvent.java
@@ -15,9 +15,12 @@
  */
 package org.onosproject.net.host;
 
+import org.joda.time.LocalDateTime;
 import org.onosproject.event.AbstractEvent;
 import org.onosproject.net.Host;
 
+import static com.google.common.base.MoreObjects.toStringHelper;
+
 /**
  * Describes end-station host event.
  */
@@ -48,6 +51,8 @@ public class HostEvent extends AbstractEvent<HostEvent.Type, Host> {
         HOST_MOVED
     }
 
+    private Host prevSubject;
+
     /**
      * Creates an event of a given type and for the specified host and the
      * current time.
@@ -70,4 +75,39 @@ public class HostEvent extends AbstractEvent<HostEvent.Type, Host> {
         super(type, host, time);
     }
 
+    /**
+     * Creates an event with previous subject.
+     *
+     * The previous subject is ignored if the type is not moved or updated
+     *
+     * @param type host event type
+     * @param host event host subject
+     * @param prevSubject previous host subject
+     */
+    public HostEvent(Type type, Host host, Host prevSubject) {
+        super(type, host);
+        if (type == Type.HOST_MOVED || type == Type.HOST_UPDATED) {
+            this.prevSubject = prevSubject;
+        }
+    }
+
+    /**
+     * Gets the previous subject in this host event.
+     *
+     * @return the previous subject, or null if previous subject is not
+     *         specified.
+     */
+    public Host prevSubject() {
+        return this.prevSubject;
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this)
+                .add("time", new LocalDateTime(time()))
+                .add("type", type())
+                .add("subject", subject())
+                .add("prevSubject", prevSubject())
+                .toString();
+    }
 }