[ONOS-6607] Get active flow entries count in FlowRuleService

Change-Id: I68b4d916f92427c06a82d3622fcc05738f64541c
diff --git a/web/api/src/main/resources/definitions/StatisticsFlowsActiveEntries.json b/web/api/src/main/resources/definitions/StatisticsFlowsActiveEntries.json
new file mode 100644
index 0000000..9a677d7
--- /dev/null
+++ b/web/api/src/main/resources/definitions/StatisticsFlowsActiveEntries.json
@@ -0,0 +1,38 @@
+{
+  "type": "object",
+  "title": "statistics",
+  "required": [
+    "statistics"
+  ],
+  "properties": {
+    "statistics": {
+      "type": "array",
+      "required": [
+        "statistics"
+      ],
+      "xml": {
+        "name": "statistics",
+        "wrapped": true
+      },
+      "items": {
+        "type": "object",
+        "title": "statistics",
+        "required": [
+          "device",
+          "activeEntries"
+        ],
+        "properties": {
+          "device": {
+            "type": "string",
+            "example": "of:0000000000000001"
+          },
+          "activeEntries": {
+            "type": "integer",
+            "format": "int64",
+            "example": 0
+          }
+        }
+      }
+    }
+  }
+}
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