API for LLDP, NS, NA, ARP counter added in Packet stats app

Change-Id: If49f35d2fb302496f59e095a2ae6062ca48108ad
diff --git a/apps/packet-stats/web/src/main/java/org/onosproject/packetstats/rest/PacketStatsWebResource.java b/apps/packet-stats/web/src/main/java/org/onosproject/packetstats/rest/PacketStatsWebResource.java
new file mode 100644
index 0000000..a6bf190
--- /dev/null
+++ b/apps/packet-stats/web/src/main/java/org/onosproject/packetstats/rest/PacketStatsWebResource.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2014-present Open Networking Foundation
+ *
+ * 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.packetstats.rest;
+import javax.ws.rs.Path;
+import javax.ws.rs.GET;
+import javax.ws.rs.Produces;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+import org.onosproject.rest.AbstractWebResource;
+import com.codahale.metrics.MetricFilter;
+import com.codahale.metrics.Counter;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onlab.metrics.MetricsService;
+import java.util.Map;
+
+/**
+ * Packet Stats REST API.
+ */
+public class PacketStatsWebResource extends AbstractWebResource {
+    private final ObjectMapper mapper = new ObjectMapper();
+    private static final String METRIC_NAME = null;
+    MetricFilter filter = METRIC_NAME != null ? (name, metric) -> name.equals(METRIC_NAME) : MetricFilter.ALL;
+
+    @GET
+    @Path("counters")
+    @Produces(MediaType.APPLICATION_JSON)
+    public Response packetStatsCounters() {
+        ObjectNode node = getPacketStatsCountersJson();
+        return Response.status(200).entity(node).build();
+    }
+
+    private ObjectNode getPacketStatsCountersJson() {
+        MetricsService service = get(MetricsService.class);
+        ObjectNode node = mapper.createObjectNode();
+        ObjectNode pktCounterNode = mapper.createObjectNode();
+        Map<String, Counter> counters = service.getCounters(filter);
+
+        Counter arpCounter = counters.get("packetStatisticsComponent.arpFeature.arpPC");
+        Counter lldpCounter = counters.get("packetStatisticsComponent.lldpFeature.lldpPC");
+        Counter nsCounter = counters.get("packetStatisticsComponent.nbrSolicitFeature.nbrSolicitPC");
+        Counter naCounter = counters.get("packetStatisticsComponent.nbrAdvertFeature.nbrAdvertPC");
+
+        pktCounterNode.put("arpCounter", arpCounter.getCount());
+        pktCounterNode.put("lldpCounter", lldpCounter.getCount());
+        pktCounterNode.put("nsCounter", nsCounter.getCount());
+        pktCounterNode.put("naCounter", naCounter.getCount());
+
+        node.put("packet_stats_counters", pktCounterNode);
+        return node;
+
+    }
+}