Examples: incorporate latest change of NDNPing Class

Change-Id: I01d59de621992a87c082074766dc18e9a7b549a2
diff --git a/examples/nlsr/mcn_failure.py b/examples/nlsr/mcn_failure.py
index 1bd0449..decb586 100644
--- a/examples/nlsr/mcn_failure.py
+++ b/examples/nlsr/mcn_failure.py
@@ -1,6 +1,6 @@
 # -*- Mode:python; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
 #
-# Copyright (C) 2015-2019, The University of Memphis,
+# Copyright (C) 2015-2021, The University of Memphis,
 #                          Arizona Board of Regents,
 #                          Regents of the University of California.
 #
@@ -32,7 +32,7 @@
 from minindn.apps.nlsr import Nlsr
 from minindn.helpers.experiment import Experiment
 from minindn.helpers.nfdc import Nfdc
-from minindn.helpers.ndnpingclient import NDNPingClient
+from minindn.helpers.ndnping import NDNPing
 
 from nlsr_common import getParser
 
@@ -63,7 +63,7 @@
     if args.nPings != 0:
         Experiment.setupPing([mcn], Nfdc.STRATEGY_BEST_ROUTE)
         for nodeToPing in pingedDict[mcn]:
-            NDNPingClient.ping(mcn, nodeToPing, PING_COLLECTION_TIME_AFTER_RECOVERY)
+            NDNPing.ping(mcn, nodeToPing, nPings=PING_COLLECTION_TIME_AFTER_RECOVERY)
 
         time.sleep(PING_COLLECTION_TIME_AFTER_RECOVERY)
 
diff --git a/examples/nlsr/multiple_failure.py b/examples/nlsr/multiple_failure.py
index 48d1afd..0833ff1 100644
--- a/examples/nlsr/multiple_failure.py
+++ b/examples/nlsr/multiple_failure.py
@@ -1,6 +1,6 @@
 # -*- Mode:python; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
 #
-# Copyright (C) 2015-2019, The University of Memphis,
+# Copyright (C) 2015-2021, The University of Memphis,
 #                          Arizona Board of Regents,
 #                          Regents of the University of California.
 #
@@ -32,7 +32,7 @@
 from minindn.apps.nlsr import Nlsr
 from minindn.helpers.experiment import Experiment
 from minindn.helpers.nfdc import Nfdc
-from minindn.helpers.ndnpingclient import NDNPingClient
+from minindn.helpers.ndnping import NDNPing
 
 from nlsr_common import getParser
 
@@ -45,7 +45,7 @@
     FAILURE_INTERVAL = 60
     RECOVERY_INTERVAL = 60
 
-    # This is the number of pings required to make it through the full experiment
+    # Number of pings required to make it through the full experiment
     nInitialPings = (PING_COLLECTION_TIME_BEFORE_FAILURE +
                      len(ndn.net.hosts) * (FAILURE_INTERVAL + RECOVERY_INTERVAL))
     print('Scheduling with {} initial pings'.format(nInitialPings))
@@ -82,11 +82,11 @@
 
         # Restart pings
         for nodeToPing in pingedDict[host]:
-            NDNPingClient.ping(host, nodeToPing, nPings)
+            NDNPing.ping(host, nodeToPing, nPings=nPings)
 
         time.sleep(RECOVERY_INTERVAL - recovery_time)
 
-    #Experiment.checkConvergence(ndn, ndn.net.hosts, args.ctime, quit=True)
+    Experiment.checkConvergence(ndn, ndn.net.hosts, args.ctime, quit=True)
 
 if __name__ == '__main__':
     setLogLevel('info')
diff --git a/examples/wifi/wifi_ping.py b/examples/wifi/wifi_ping.py
index bd48b15..a712342 100644
--- a/examples/wifi/wifi_ping.py
+++ b/examples/wifi/wifi_ping.py
@@ -27,7 +27,7 @@
 from minindn.apps.app_manager import AppManager
 from minindn.apps.nfd import Nfd
 from minindn.helpers.nfdc import Nfdc
-from minindn.helpers.ndnpingclient import NDNPingClient
+from minindn.helpers.ndnping import NDNPing
 from time import sleep
 # This experiment uses the singleap topology and is intended to be a basic
 # test case where we see if two nodes can send interests to each other.
@@ -64,13 +64,14 @@
     nfds = AppManager(ndnwifi, ndnwifi.net.stations, Nfd)
 
     info("Starting pingserver...")
-    ping_server_proc = getPopen(b, "ndnpingserver /example")
+    NDNPing.startPingServer(b, "/example")
     Nfdc.createFace(a, b.IP())
     Nfdc.registerRoute(a, "/example", b.IP())
 
     info("Starting ping...")
-    NDNPingClient.ping(a, "/example", 10)
+    NDNPing.ping(a, "/example", nPings=10)
 
+    sleep(10)
     # Start the CLI
     MiniNDNWifiCLI(ndnwifi.net)
     ndnwifi.net.stop()
diff --git a/minindn/helpers/ndnping.py b/minindn/helpers/ndnping.py
index 5d2f3d4..b1a4081 100644
--- a/minindn/helpers/ndnping.py
+++ b/minindn/helpers/ndnping.py
@@ -1,6 +1,6 @@
 # -*- Mode:python; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
 #
-# Copyright (C) 2015-2020, The University of Memphis,
+# Copyright (C) 2015-2021, The University of Memphis,
 #                          Arizona Board of Regents,
 #                          Regents of the University of California.
 #
@@ -28,7 +28,8 @@
 class NDNPing(object):
     @staticmethod
     def ping(source, prefix, pingDataFile="output-client", nPings=1, interval=None, timeout=None,
-            starting_seq_num=None, identifier=None, allow_stale_data=False, print_timestamp=True, sleepTime=0.2):
+             starting_seq_num=None, identifier=None, allow_stale_data=False, print_timestamp=True,
+             sleepTime=0.2):
         print('Scheduling ping(s) from {} for {}'.format(source.name, prefix))
         # Use '&' to run in background and perform parallel pings
         source.cmd("mkdir -p ping-data")
@@ -46,8 +47,9 @@
         ))
         time.sleep(sleepTime)
 
-    def startPingServer(source, prefix, pingDataFile="output-server", freshness=None, satisfy=None, 
-            size=None, timestamp=False, quiet=False):
+    @staticmethod
+    def startPingServer(source, prefix, pingDataFile="output-server", freshness=None, satisfy=None,
+                        size=None, timestamp=False, quiet=False):
         """
         Start a pingserver
          :param string preifx: prefix to start pingserver on