[ONOS-4438] Add codecs for mastership REST API

Add codecs for RoleInfo, MastershipTerm and MastershipRole.

Change-Id: I1135c7fc0ed591446d6268229b54fda70391fdb9
diff --git a/core/common/src/main/java/org/onosproject/codec/impl/CodecManager.java b/core/common/src/main/java/org/onosproject/codec/impl/CodecManager.java
index c03a3fa..908e8ee 100644
--- a/core/common/src/main/java/org/onosproject/codec/impl/CodecManager.java
+++ b/core/common/src/main/java/org/onosproject/codec/impl/CodecManager.java
@@ -23,6 +23,7 @@
 import org.apache.felix.scr.annotations.Service;
 import org.onlab.packet.Ethernet;
 import org.onosproject.cluster.ControllerNode;
+import org.onosproject.cluster.RoleInfo;
 import org.onosproject.codec.CodecService;
 import org.onosproject.codec.JsonCodec;
 import org.onosproject.core.Application;
@@ -31,12 +32,14 @@
 import org.onosproject.incubator.net.virtual.VirtualLink;
 import org.onosproject.incubator.net.virtual.VirtualNetwork;
 import org.onosproject.incubator.net.virtual.VirtualPort;
+import org.onosproject.mastership.MastershipTerm;
 import org.onosproject.net.Annotations;
 import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.Device;
 import org.onosproject.net.Host;
 import org.onosproject.net.HostLocation;
 import org.onosproject.net.Link;
+import org.onosproject.net.MastershipRole;
 import org.onosproject.net.Path;
 import org.onosproject.net.Port;
 import org.onosproject.net.device.PortStatistics;
@@ -136,6 +139,9 @@
         registerCodec(VirtualDevice.class, new VirtualDeviceCodec());
         registerCodec(VirtualPort.class, new VirtualPortCodec());
         registerCodec(VirtualLink.class, new VirtualLinkCodec());
+        registerCodec(MastershipTerm.class, new MastershipTermCodec());
+        registerCodec(MastershipRole.class, new MastershipRoleCodec());
+        registerCodec(RoleInfo.class, new RoleInfoCodec());
         log.info("Started");
     }
 
diff --git a/core/common/src/main/java/org/onosproject/codec/impl/MastershipRoleCodec.java b/core/common/src/main/java/org/onosproject/codec/impl/MastershipRoleCodec.java
new file mode 100644
index 0000000..9a7f7f9
--- /dev/null
+++ b/core/common/src/main/java/org/onosproject/codec/impl/MastershipRoleCodec.java
@@ -0,0 +1,76 @@
+/*
+ * 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.codec.impl;
+
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onosproject.codec.CodecContext;
+import org.onosproject.codec.JsonCodec;
+import org.onosproject.net.MastershipRole;
+import org.slf4j.Logger;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.onlab.util.Tools.nullIsIllegal;
+import static org.onosproject.net.MastershipRole.MASTER;
+import static org.onosproject.net.MastershipRole.NONE;
+import static org.onosproject.net.MastershipRole.STANDBY;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Codec for mastership role.
+ */
+public final class MastershipRoleCodec extends JsonCodec<MastershipRole> {
+    private final Logger log = getLogger(getClass());
+
+    // JSON field names
+    private static final String ROLE = "role";
+
+    private static final String MISSING_MEMBER_MESSAGE = " member is required in MastershipRole";
+
+    @Override
+    public ObjectNode encode(MastershipRole mastershipRole, CodecContext context) {
+        checkNotNull(mastershipRole, "MastershipRole cannot be null");
+        ObjectNode result = context.mapper().createObjectNode()
+                .put(ROLE, mastershipRole.name());
+        return result;
+    }
+
+    @Override
+    public MastershipRole decode(ObjectNode json, CodecContext context) {
+        if (json == null || !json.isObject()) {
+            return null;
+        }
+
+        String roleJson = nullIsIllegal(json.get(ROLE),
+                ROLE + MISSING_MEMBER_MESSAGE).asText();
+        MastershipRole mastershipRole;
+        switch (roleJson) {
+            case "MASTER":
+                mastershipRole = MASTER;
+                break;
+            case "STANDBY":
+                mastershipRole = STANDBY;
+                break;
+            case "NONE":
+                mastershipRole = NONE;
+                break;
+            default:
+                log.warn("The mastership role {} is not defined.", roleJson);
+                return null;
+        }
+
+        return mastershipRole;
+    }
+}
diff --git a/core/common/src/main/java/org/onosproject/codec/impl/MastershipTermCodec.java b/core/common/src/main/java/org/onosproject/codec/impl/MastershipTermCodec.java
new file mode 100644
index 0000000..c8f3915
--- /dev/null
+++ b/core/common/src/main/java/org/onosproject/codec/impl/MastershipTermCodec.java
@@ -0,0 +1,64 @@
+/*
+ * 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.codec.impl;
+
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onosproject.cluster.NodeId;
+import org.onosproject.codec.CodecContext;
+import org.onosproject.codec.JsonCodec;
+import org.onosproject.mastership.MastershipTerm;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.onlab.util.Tools.nullIsIllegal;
+
+/**
+ * Codec for mastership term.
+ */
+public class MastershipTermCodec extends JsonCodec<MastershipTerm> {
+
+    // JSON field names
+    private static final String MASTER = "master";
+    private static final String TERM_NUMBER = "termNumber";
+
+    private static final String MISSING_MEMBER_MESSAGE = " member is required in MastershipTerm";
+
+    @Override
+    public ObjectNode encode(MastershipTerm term, CodecContext context) {
+        checkNotNull(term, "Mastership term cannot be null");
+        ObjectNode result = context.mapper().createObjectNode()
+                .put(MASTER, term.master().id())
+                .put(TERM_NUMBER, term.termNumber());
+
+        return result;
+    }
+
+    @Override
+    public MastershipTerm decode(ObjectNode json, CodecContext context) {
+        if (json == null || !json.isObject()) {
+            return null;
+        }
+
+        // node identifier of master
+        NodeId nodeId = NodeId.nodeId(nullIsIllegal(json.get(MASTER),
+                MASTER + MISSING_MEMBER_MESSAGE).asText());
+
+        // term number
+        long termNumber = nullIsIllegal(json.get(TERM_NUMBER),
+                TERM_NUMBER + MISSING_MEMBER_MESSAGE).asLong();
+
+        return MastershipTerm.of(nodeId, termNumber);
+    }
+}
diff --git a/core/common/src/main/java/org/onosproject/codec/impl/RoleInfoCodec.java b/core/common/src/main/java/org/onosproject/codec/impl/RoleInfoCodec.java
new file mode 100644
index 0000000..c63c078
--- /dev/null
+++ b/core/common/src/main/java/org/onosproject/codec/impl/RoleInfoCodec.java
@@ -0,0 +1,88 @@
+/*
+ * 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.codec.impl;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onosproject.cluster.NodeId;
+import org.onosproject.cluster.RoleInfo;
+import org.onosproject.codec.CodecContext;
+import org.onosproject.codec.JsonCodec;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.IntStream;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.onlab.util.Tools.nullIsIllegal;
+
+/**
+ * Codec for role info.
+ */
+public final class RoleInfoCodec extends JsonCodec<RoleInfo> {
+
+    // JSON field names
+    private static final String MASTER = "master";
+    private static final String BACKUPS = "backups";
+
+    private static final String MISSING_MEMBER_MESSAGE = " member is required in MastershipTerm";
+
+    @Override
+    public ObjectNode encode(RoleInfo roleInfo, CodecContext context) {
+        checkNotNull(roleInfo, "RoleInfo cannot be null");
+
+        ObjectNode result = context.mapper().createObjectNode();
+
+        if (roleInfo.master() != null) {
+            result.put(MASTER, roleInfo.master().id());
+        }
+
+        ArrayNode backups = context.mapper().createArrayNode();
+        roleInfo.backups().forEach(backup -> backups.add(backup.id()));
+
+        if (roleInfo.backups().size() != 0) {
+            result.set(BACKUPS, backups);
+        }
+
+        return result;
+    }
+
+    @Override
+    public RoleInfo decode(ObjectNode json, CodecContext context) {
+        if (json == null || !json.isObject()) {
+            return null;
+        }
+
+        // parse node identifier of master
+        NodeId nodeId = json.get(MASTER) == null ?
+                null : NodeId.nodeId(json.get(MASTER).asText());
+
+        // parse node identifier of backups
+        List<NodeId> backups = new ArrayList<>();
+
+        ArrayNode backupsJson = (ArrayNode) nullIsIllegal(json.get(BACKUPS),
+                BACKUPS + MISSING_MEMBER_MESSAGE);
+
+        IntStream.range(0, backupsJson.size()).forEach(i -> {
+            JsonNode backupJson = nullIsIllegal(backupsJson.get(i),
+                    "Backup node id cannot be null");
+            backups.add(NodeId.nodeId(backupJson.asText()));
+        });
+
+        return new RoleInfo(nodeId, backups);
+    }
+}