[ONOS-7731] Update api interface & implementation of openstack vtap app

Change-Id: I7c3c7888b00a7357b13e3b1756e9cd0a1bb6a5c0
diff --git a/apps/openstackvtap/app/src/main/java/org/onosproject/openstackvtap/codec/OpenstackVtapNetworkCodec.java b/apps/openstackvtap/app/src/main/java/org/onosproject/openstackvtap/codec/OpenstackVtapNetworkCodec.java
new file mode 100644
index 0000000..6dd6b5c
--- /dev/null
+++ b/apps/openstackvtap/app/src/main/java/org/onosproject/openstackvtap/codec/OpenstackVtapNetworkCodec.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2018-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.openstackvtap.codec;
+
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onlab.packet.IpAddress;
+import org.onosproject.codec.CodecContext;
+import org.onosproject.codec.JsonCodec;
+import org.onosproject.openstackvtap.api.OpenstackVtapNetwork;
+import org.onosproject.openstackvtap.impl.DefaultOpenstackVtapNetwork;
+import org.slf4j.Logger;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Openstack vtap network codec used for serializing and de-serializing JSON string.
+ */
+public final class OpenstackVtapNetworkCodec extends JsonCodec<OpenstackVtapNetwork> {
+
+    private final Logger log = getLogger(getClass());
+
+    private static final String MODE = "mode";
+    private static final String NETWORK_ID = "networkId";
+    private static final String SERVER_IP = "serverIp";
+    private static final String NODES = "nodes";
+
+    private static final String JSON_NULL_MESSAGE = "% cannot be null";
+    private static final String JSON_MISSING_MESSAGE = "% is required";
+    private static final String JSON_TYPE_MESSAGE = "% is not json object type";
+
+    @Override
+    public ObjectNode encode(OpenstackVtapNetwork network, CodecContext context) {
+        checkNotNull(network, JSON_NULL_MESSAGE, "OpenstackVtapNetwork object");
+
+        ObjectNode result = context.mapper().createObjectNode()
+                .put(MODE, network.mode().toString())
+                .put(NETWORK_ID, network.networkId())
+                .put(SERVER_IP, network.serverIp().toString());
+
+        return result;
+    }
+
+    @Override
+    public OpenstackVtapNetwork decode(ObjectNode json, CodecContext context) {
+        checkNotNull(json, JSON_NULL_MESSAGE, "OpenstackVtapNetwork json");
+        checkState(json.isObject(), JSON_TYPE_MESSAGE, "OpenstackVtapNetwork json");
+
+        DefaultOpenstackVtapNetwork.Builder builder = DefaultOpenstackVtapNetwork.builder()
+                .mode(OpenstackVtapNetwork.Mode.valueOf(checkNotNull(json.get(MODE).asText(null),
+                        JSON_MISSING_MESSAGE, MODE)))
+                .networkId(json.get(NETWORK_ID).asInt(0))
+                .serverIp(IpAddress.valueOf(checkNotNull(json.get(SERVER_IP).asText(null),
+                        JSON_MISSING_MESSAGE, SERVER_IP)));
+
+        log.debug("OpenstackVtapNetwork is {}", builder.build().toString());
+        return builder.build();
+    }
+}