[ONOS-5012] implement RESTconf server

 - fix javadoc longer than 80 char limit
 - fix javadoc that missing @params
 - chain calls to StringBuilder.append()
 - combine constant strings in place

Change-Id: Ie2ef4fd4c19e955ad2d5a5584f5017a842abb790
diff --git a/protocols/restconf/server/utils/src/test/java/org/onosproject/restconf/utils/parser/json/DefaultJsonWalkerTest.java b/protocols/restconf/server/utils/src/test/java/org/onosproject/restconf/utils/parser/json/DefaultJsonWalkerTest.java
new file mode 100644
index 0000000..c82f0f8
--- /dev/null
+++ b/protocols/restconf/server/utils/src/test/java/org/onosproject/restconf/utils/parser/json/DefaultJsonWalkerTest.java
@@ -0,0 +1,144 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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.restconf.utils.parser.json;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.junit.Before;
+import org.junit.Test;
+import org.onosproject.protocol.restconf.server.utils.parser.api.JsonListener;
+import org.onosproject.protocol.restconf.server.utils.parser.json.DefaultJsonWalker;
+
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.core.Is.is;
+
+public class DefaultJsonWalkerTest {
+
+    private static final String[] EXP_TEXT_ARRAY = {
+            "Enter: type is OBJECT name is null",
+            "Enter: type is STRING name is name",
+            "Exit: type is STRING",
+            "Enter: type is STRING name is surname",
+            "Exit: type is STRING",
+            "Exit: type is OBJECT"
+    };
+
+    private static final String[] EXP_NODE_LIST_ARRAY = {
+            "Enter: type is OBJECT name is null",
+            "Enter: type is STRING name is surname",
+            "Exit: type is STRING",
+            "Enter: type is ARRAY name is networklist",
+            "Exit: type is ARRAY",
+            "Exit: type is OBJECT"
+    };
+
+    private static final String[] EXP_NODE_WITH_ARRAY = {
+            "Enter: type is OBJECT name is null",
+            "Enter: type is STRING name is surname",
+            "Exit: type is STRING",
+            "Enter: type is ARRAY name is networklist",
+            "Enter: type is OBJECT name is null",
+            "Enter: type is STRING name is network-id",
+            "Exit: type is STRING",
+            "Enter: type is STRING name is server-provided",
+            "Exit: type is STRING",
+            "Exit: type is OBJECT",
+            "Enter: type is OBJECT name is null",
+            "Enter: type is STRING name is network-id",
+            "Exit: type is STRING",
+            "Enter: type is STRING name is server-provided",
+            "Exit: type is STRING",
+            "Exit: type is OBJECT",
+            "Enter: type is OBJECT name is null",
+            "Enter: type is STRING name is network-id",
+            "Exit: type is STRING",
+            "Enter: type is STRING name is server-provided",
+            "Exit: type is STRING",
+            "Exit: type is OBJECT",
+            "Exit: type is ARRAY",
+            "Exit: type is OBJECT"
+    };
+    private static final String WRONG_CONTENT_MSG = "Wrong content in array";
+
+    private final List<String> logger = new ArrayList<>();
+
+    DefaultJsonWalker defaultJsonWalker = new DefaultJsonWalker();
+    InternalJsonListener jsonListener = new InternalJsonListener();
+
+    ObjectNode arrayNode;
+    ObjectNode textNode;
+    ObjectNode listNode;
+
+    @Before
+    public void setup() throws Exception {
+        textNode = loadJsonFile("/textNode.json");
+        listNode = loadJsonFile("/listNode.json");
+        arrayNode = loadJsonFile("/arrayNode.json");
+    }
+
+    private ObjectNode loadJsonFile(String path) throws Exception {
+        InputStream jsonStream = getClass().getResourceAsStream(path);
+        ObjectMapper mapper = new ObjectMapper();
+        return (ObjectNode) mapper.readTree(jsonStream);
+    }
+
+    private void assertWalkResult(String[] expectArray, List<String> logger) {
+        for (int i = 0; i < expectArray.length; i++) {
+            assertThat(WRONG_CONTENT_MSG,
+                       true,
+                       is(logger.get(i).contentEquals(expectArray[i])));
+        }
+    }
+
+    @Test
+    public void testWalkTextNode() throws Exception {
+
+        defaultJsonWalker.walk(jsonListener, null, textNode);
+        assertWalkResult(EXP_TEXT_ARRAY, logger);
+    }
+
+    @Test
+    public void testWalkNodeWithList() throws Exception {
+        defaultJsonWalker.walk(jsonListener, null, listNode);
+        assertWalkResult(EXP_NODE_LIST_ARRAY, logger);
+    }
+
+    @Test
+    public void testWalkNodeWithArray() throws Exception {
+        defaultJsonWalker.walk(jsonListener, null, arrayNode);
+        assertWalkResult(EXP_NODE_WITH_ARRAY, logger);
+    }
+
+    private class InternalJsonListener implements JsonListener {
+
+        @Override
+        public void enterJsonNode(String fieldName, JsonNode node) {
+            logger.add("Enter: type is " + node.getNodeType() + " name is " +
+                               fieldName);
+        }
+
+        @Override
+        public void exitJsonNode(JsonNode node) {
+            logger.add("Exit: type is " + node.getNodeType());
+        }
+    }
+}
\ No newline at end of file
diff --git a/protocols/restconf/server/utils/src/test/resources/arrayNode.json b/protocols/restconf/server/utils/src/test/resources/arrayNode.json
new file mode 100644
index 0000000..2035e82
--- /dev/null
+++ b/protocols/restconf/server/utils/src/test/resources/arrayNode.json
@@ -0,0 +1,18 @@
+{
+  "surname": "Bangalore",
+  "networklist":[
+    {
+      "network-id": "520",
+      "server-provided": "123"
+    },
+    {
+      "network-id": "521",
+      "server-provided": "124"
+    },
+    {
+      "network-id": "523",
+      "server-provided": "125"
+    }
+
+  ]
+}
\ No newline at end of file
diff --git a/protocols/restconf/server/utils/src/test/resources/listNode.json b/protocols/restconf/server/utils/src/test/resources/listNode.json
new file mode 100644
index 0000000..c7902f5
--- /dev/null
+++ b/protocols/restconf/server/utils/src/test/resources/listNode.json
@@ -0,0 +1,8 @@
+{
+  "surname": "Bangalore",
+  "networklist":[
+    "0.79",
+    "1.04",
+    "3.14"
+  ]
+}
\ No newline at end of file
diff --git a/protocols/restconf/server/utils/src/test/resources/textNode.json b/protocols/restconf/server/utils/src/test/resources/textNode.json
new file mode 100644
index 0000000..8894cfb
--- /dev/null
+++ b/protocols/restconf/server/utils/src/test/resources/textNode.json
@@ -0,0 +1,4 @@
+{
+  "name": "Huawei",
+  "surname": "Bangalore"
+}
\ No newline at end of file