Add keystone and neutron config classes and codec with unit tests

Change-Id: Ia89f5be9bac88927a383d56d56413ba23e3e5eb3
diff --git a/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/codec/KeystoneConfigCodec.java b/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/codec/KeystoneConfigCodec.java
new file mode 100644
index 0000000..95da63a
--- /dev/null
+++ b/apps/openstacknode/app/src/main/java/org/onosproject/openstacknode/codec/KeystoneConfigCodec.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.openstacknode.codec;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onosproject.codec.CodecContext;
+import org.onosproject.codec.JsonCodec;
+import org.onosproject.openstacknode.api.KeystoneConfig;
+import org.onosproject.openstacknode.api.OpenstackAuth;
+import org.onosproject.openstacknode.api.DefaultKeystoneConfig;
+
+import static org.onlab.util.Tools.nullIsIllegal;
+
+/**
+ * Keystone config codec used for serializing and de-serializing JSON string.
+ */
+public final class KeystoneConfigCodec extends JsonCodec<KeystoneConfig> {
+
+    private static final String ENDPOINT = "endpoint";
+    private static final String AUTHENTICATION = "authentication";
+
+    private static final String MISSING_MESSAGE = " is required in OpenstackNode";
+
+    @Override
+    public ObjectNode encode(KeystoneConfig entity, CodecContext context) {
+        ObjectNode result = context.mapper().createObjectNode()
+                .put(ENDPOINT, entity.endpoint());
+
+        ObjectNode authJson = context.codec(OpenstackAuth.class)
+                .encode(entity.authentication(), context);
+        result.set(AUTHENTICATION, authJson);
+
+        return result;
+    }
+
+    @Override
+    public KeystoneConfig decode(ObjectNode json, CodecContext context) {
+        if (json == null || !json.isObject()) {
+            return null;
+        }
+
+        String endpoint = nullIsIllegal(json.get(ENDPOINT).asText(),
+                ENDPOINT + MISSING_MESSAGE);
+
+        // parse authentication
+        JsonNode authJson = nullIsIllegal(json.get(AUTHENTICATION),
+                AUTHENTICATION + MISSING_MESSAGE);
+
+
+        final JsonCodec<OpenstackAuth> authCodec = context.codec(OpenstackAuth.class);
+        OpenstackAuth auth = authCodec.decode((ObjectNode) authJson.deepCopy(), context);
+
+        return DefaultKeystoneConfig.builder()
+                .endpoint(endpoint)
+                .authentication(auth)
+                .build();
+    }
+}