From 55df7237fe09683410e8f6911fc3a67ea934bd57 Mon Sep 17 00:00:00 2001
From: Tom Henderson <tomh@tomh.org>
Date: Wed, 8 Aug 2018 16:31:39 -0700
Subject: [PATCH] network:  Add ApplicationContainer::StartWithJitter()

---
 CHANGES.html                                |  1 +
 RELEASE_NOTES                               |  2 ++
 src/network/helper/application-container.cc | 14 ++++++++++++++
 src/network/helper/application-container.h  | 14 ++++++++++++++
 4 files changed, 31 insertions(+)

diff --git a/CHANGES.html b/CHANGES.html
index c68f32087..5e9cfcdf5 100644
--- a/CHANGES.html
+++ b/CHANGES.html
@@ -63,6 +63,7 @@ nodes to be placed outside of buildings defined in the scenario.</li>
     hash of various fields of the packet header (depending on the packet type).</li>
   <li> Added a priority queue disc (PrioQueueDisc).</li>
   <li> Added a new trace source in StaWifiMac for tracing beacon arrivals</li>
+  <li> Added a new helper method to ApplicationContainer to start applications with some jitter around the start time</li>
 </ul>
 <h2>Changes to existing API:</h2>
 <ul>
diff --git a/RELEASE_NOTES b/RELEASE_NOTES
index 8c8cff901..896a67279 100644
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -30,6 +30,8 @@ New user-visible features
   that are located within buildings defined in the scenario.
 - (tcp) Added PRR as recovery algorithm
 - (wifi) Add a new trace source to StaWifiMac to trace beacon arrivals
+- (network) Add a method to allow random variable-based jitter to be added
+  to the start times of applications in a container.
 
 Bugs fixed
 ----------
diff --git a/src/network/helper/application-container.cc b/src/network/helper/application-container.cc
index 243eac34d..8c394a083 100644
--- a/src/network/helper/application-container.cc
+++ b/src/network/helper/application-container.cc
@@ -19,10 +19,13 @@
  */
 
 #include "ns3/names.h"
+#include "ns3/log.h"
 #include "application-container.h"
 
 namespace ns3 {
 
+NS_LOG_COMPONENT_DEFINE ("ApplicationContainer");
+
 ApplicationContainer::ApplicationContainer ()
 {
 }
@@ -90,6 +93,17 @@ ApplicationContainer::Start (Time start)
     }
 }
 void 
+ApplicationContainer::StartWithJitter (Time start, Ptr<RandomVariableStream> rv)
+{
+  for (Iterator i = Begin (); i != End (); ++i)
+    {
+      Ptr<Application> app = *i;
+      double value = rv->GetValue ();
+      NS_LOG_DEBUG ("Start application at time " << start.GetSeconds () + value << "s");
+      app->SetStartTime (start + Seconds (value));
+    }
+}
+void 
 ApplicationContainer::Stop (Time stop)
 {
   for (Iterator i = Begin (); i != End (); ++i)
diff --git a/src/network/helper/application-container.h b/src/network/helper/application-container.h
index 88ba9a9d4..25aef36bd 100644
--- a/src/network/helper/application-container.h
+++ b/src/network/helper/application-container.h
@@ -24,6 +24,7 @@
 #include <stdint.h>
 #include <vector>
 #include "ns3/application.h"
+#include "ns3/random-variable-stream.h"
 
 namespace ns3 {
 
@@ -193,6 +194,19 @@ public:
    */
   void Start (Time start);
 
+  /**
+   * \brief Start all of the Applications in this container at the start time 
+   * given as a parameter, plus some jitter.
+   *
+   * This method iterates through the contained Applications and calls
+   * their Start() methods with the provided start Time, plus a jitter value
+   * drawn from the provided random variable.
+   *
+   * \param start The Time at which each of the applications should start.
+   * \param rv The random variable that adds jitter (units of seconds)
+   */
+  void StartWithJitter (Time start, Ptr<RandomVariableStream> rv);
+
   /**
    * \brief Arrange for all of the Applications in this container to Stop()
    * at the Time given as a parameter.