Refactor Meter, MeterRequest, Band protobuf related translators

Change-Id: Iec01522ba2aeb1aa59655fbb4520e3488eae3ebb
diff --git a/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/BandEnumsProtoTranslator.java b/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/BandEnumsProtoTranslator.java
new file mode 100644
index 0000000..b607e1a
--- /dev/null
+++ b/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/BandEnumsProtoTranslator.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2017-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.incubator.protobuf.models.net.meter;
+
+import org.onosproject.grpc.net.meter.models.BandEnumsProto;
+import org.onosproject.net.meter.Band;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Optional;
+
+/**
+ * gRPC message conversion related utilities for band enums.
+ */
+public final class BandEnumsProtoTranslator {
+
+    private static final Logger log = LoggerFactory.getLogger(BandEnumsProtoTranslator.class);
+
+    /**
+     * Translates gRPC enum Band Type to ONOS enum.
+     *
+     * @param bandType BandType in gRPC enum
+     * @return equivalent in ONOS enum
+     */
+    public static Optional<Object> translate(BandEnumsProto.BandTypeProto bandType) {
+        switch (bandType) {
+            case DROP:
+                return Optional.of(Band.Type.DROP);
+            case REMARK:
+                return Optional.of(Band.Type.REMARK);
+            case EXPERIMENTAL:
+                return Optional.of(Band.Type.EXPERIMENTAL);
+            default:
+                log.warn("Unrecognized BandType gRPC message: {}", bandType);
+                return Optional.empty();
+        }
+    }
+
+    // Utility class not intended for instantiation.
+    private BandEnumsProtoTranslator() {}
+}
diff --git a/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/BandProtoTranslator.java b/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/BandProtoTranslator.java
new file mode 100644
index 0000000..c5448f1
--- /dev/null
+++ b/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/BandProtoTranslator.java
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2017-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.incubator.protobuf.models.net.meter;
+
+import org.onosproject.grpc.net.meter.models.BandEnumsProto;
+import org.onosproject.grpc.net.meter.models.BandProtoOuterClass.BandProto;
+import org.onosproject.net.meter.Band;
+import org.onosproject.net.meter.DefaultBand;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * gRPC message conversion related utilities for band service.
+ */
+public final class BandProtoTranslator {
+
+    private static final Logger log = LoggerFactory.getLogger(BandProtoTranslator.class);
+
+    /**
+     * Translates gRPC Band to {@link Band}.
+     *
+     * @param gBand gRPC message
+     * @return {@link Band}
+     */
+    public static Band translate(BandProto gBand) {
+        Band.Type type = (Band.Type) BandEnumsProtoTranslator.translate(gBand.getType()).get();
+        long rate = gBand.getRate();
+        long burstSize = gBand.getBurst();
+        short prec = (short) gBand.getDropPrecedence();
+        Band band = new DefaultBand(type, rate, burstSize, prec);
+        return band;
+    }
+
+    /**
+     * Translates gRPC List Bands to Collection Band.
+     *
+     * @param listBands gRPC message
+     * @return Collection Band
+     */
+    public static Collection<Band> translate(List<BandProto>  listBands) {
+        Collection<Band> bands = new ArrayList<>();
+        listBands.forEach(d -> bands.add(translate(d)));
+        return bands;
+    }
+
+    /**
+     * Translates ONOS enum Band Type to gRPC enum.
+     *
+     * @param bandType BandType in ONOS enum
+     * @return equivalent in gRPC enum
+     */
+    public static BandEnumsProto.BandTypeProto translate(Band.Type bandType) {
+        switch (bandType) {
+            case DROP:
+                return BandEnumsProto.BandTypeProto.DROP;
+            case REMARK:
+                return BandEnumsProto.BandTypeProto.REMARK;
+            case EXPERIMENTAL:
+                return BandEnumsProto.BandTypeProto.EXPERIMENTAL;
+            default:
+                log.warn("Unrecognized BandType ONOS message: {}", bandType);
+                return BandEnumsProto.BandTypeProto.UNRECOGNIZED;
+        }
+    }
+
+    // Utility class not intended for instantiation.
+    private BandProtoTranslator() {}
+}
diff --git a/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/MeterEnumsProtoTranslator.java b/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/MeterEnumsProtoTranslator.java
new file mode 100644
index 0000000..6b7fb3e
--- /dev/null
+++ b/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/MeterEnumsProtoTranslator.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright 2017-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.incubator.protobuf.models.net.meter;
+
+import org.onosproject.grpc.net.meter.models.MeterEnumsProto;
+import org.onosproject.net.meter.Meter;
+import org.onosproject.net.meter.MeterState;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Optional;
+
+/**
+ * gRPC message conversion related utilities for meter enums.
+ */
+public final class MeterEnumsProtoTranslator {
+
+    private static final Logger log = LoggerFactory.getLogger(MeterEnumsProtoTranslator.class);
+
+    /**
+     * Translates gRPC enum MeterUnit to ONOS enum.
+     *
+     * @param unit meterUnit in gRPC enum
+     * @return equivalent in ONOS enum
+     */
+    public static Optional<Object> translate(MeterEnumsProto.MeterUnitProto unit) {
+        switch (unit) {
+            case PKTS_PER_SEC:
+                return Optional.of(Meter.Unit.PKTS_PER_SEC);
+            case KB_PER_SEC:
+                return Optional.of(Meter.Unit.KB_PER_SEC);
+            default:
+                log.warn("Unrecognized MeterUnit gRPC message: {}", unit);
+                return Optional.empty();
+        }
+    }
+
+    /**
+     * Translates ONOS enum Meter.Unit Type to gRPC enum.
+     *
+     * @param unit Meter.Unit in ONOS enum
+     * @return equivalent in gRPC enum
+     */
+    public static MeterEnumsProto.MeterUnitProto translate(Meter.Unit unit) {
+        switch (unit) {
+            case PKTS_PER_SEC:
+                return MeterEnumsProto.MeterUnitProto.PKTS_PER_SEC;
+            case KB_PER_SEC:
+                return MeterEnumsProto.MeterUnitProto.KB_PER_SEC;
+            default:
+                log.warn("Unrecognized MeterUnit ONOS message: {}", unit);
+                return MeterEnumsProto.MeterUnitProto.UNRECOGNIZED;
+        }
+    }
+
+    /**
+     * Translates ONOS enum MeterState Type to gRPC enum.
+     *
+     * @param meterState MeterState in ONOS enum
+     * @return equivalent in gRPC enum
+     */
+    public static MeterEnumsProto.MeterStateProto translate(MeterState meterState) {
+        switch (meterState) {
+            case PENDING_ADD:
+                return MeterEnumsProto.MeterStateProto.PENDING_ADD;
+            case ADDED:
+                return MeterEnumsProto.MeterStateProto.ADDED;
+            case PENDING_REMOVE:
+                return MeterEnumsProto.MeterStateProto.PENDING_REMOVE;
+            case REMOVED:
+                return MeterEnumsProto.MeterStateProto.REMOVED;
+            default:
+                log.warn("Unrecognized MeterState ONOS message: {}", meterState);
+                return MeterEnumsProto.MeterStateProto.UNRECOGNIZED;
+        }
+    }
+
+    // Utility class not intended for instantiation.
+    private MeterEnumsProtoTranslator() {}
+}
diff --git a/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/MeterProtoTranslator.java b/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/MeterProtoTranslator.java
index 85f0a97..1044664 100644
--- a/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/MeterProtoTranslator.java
+++ b/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/MeterProtoTranslator.java
@@ -15,31 +15,15 @@
  */
 package org.onosproject.incubator.protobuf.models.net.meter;
 
+import com.google.common.annotations.Beta;
+import org.onosproject.grpc.net.meter.models.BandProtoOuterClass.BandProto;
+import org.onosproject.grpc.net.meter.models.MeterProtoOuterClass.MeterProto;
+import org.onosproject.incubator.protobuf.models.core.ApplicationIdProtoTranslator;
+import org.onosproject.net.meter.Meter;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import org.onosproject.net.meter.Band;
-import org.onosproject.net.meter.MeterRequest;
-import org.onosproject.net.DeviceId;
-import org.onosproject.net.meter.DefaultBand;
-import org.onosproject.net.meter.DefaultMeterRequest;
-import org.onosproject.net.meter.Meter;
-import org.onosproject.net.meter.MeterState;
-import org.onosproject.core.ApplicationId;
-import org.onosproject.core.DefaultApplicationId;
-import org.onosproject.grpc.core.models.ApplicationIdProtoOuterClass.ApplicationIdProto;
-import org.onosproject.grpc.net.meter.models.BandProtoOuterClass.BandProto;
-import org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterRequestTypeProto;
-import org.onosproject.grpc.net.meter.models.MeterRequestProtoOuterClass.MeterRequestProto;
-import org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterUnitProto;
-import org.onosproject.grpc.net.meter.models.BandEnumsProto.BandTypeProto;
-import org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterStateProto;
-import org.onosproject.grpc.net.meter.models.MeterProtoOuterClass.MeterProto;
-
-import java.util.ArrayList;
-import java.util.Collection;
 import java.util.stream.Collectors;
-import com.google.common.annotations.Beta;
 
 /**
  * gRPC message conversion related utilities for meter service.
@@ -49,219 +33,6 @@
     private static final Logger log = LoggerFactory.getLogger(MeterProtoTranslator.class);
 
     /**
-     * Translates gRPC ApplicationId to {@link ApplicationId}.
-     *
-     * @param gAppId gRPC message
-     * @return {@link ApplicationId}
-     */
-    public static ApplicationId translate(ApplicationIdProto gAppId) {
-        int id = gAppId.getId();
-        String name = gAppId.getName();
-        ApplicationId appId = new DefaultApplicationId(id, name);
-        return appId;
-    }
-
-    /**
-     * Translates gRPC Band to {@link Band}.
-     *
-     * @param gBand gRPC message
-     * @return {@link Band}
-     */
-    public static Band translate(BandProto gBand) {
-        Band.Type type = translate(gBand.getType());
-        long rate = gBand.getRate();
-        long burstSize = gBand.getBurst();
-        short prec = (short) gBand.getDropPrecedence();
-        Band band = new DefaultBand(type, rate, burstSize, prec);
-        return band;
-    }
-
-    /**
-     * Translates gRPC List Bands to Collection Band.
-     *
-     * @param listBands gRPC message
-     * @return Collection Band
-     */
-    public static Collection<Band> translate(java.util.List<BandProto>  listBands) {
-        Collection<Band> bands = new ArrayList<>();
-        listBands.forEach(d -> {
-            bands.add(translate(d));
-        });
-        return bands;
-    }
-
-    /**
-     * Translates gRPC MeterRequestType to {@link MeterRequest.Type}.
-     *
-     * @param type gRPC message
-     * @return {@link MeterRequest.Type}
-     */
-    public static MeterRequest.Type translate(MeterRequestTypeProto type) {
-        switch (type) {
-            case ADD:
-                return MeterRequest.Type.ADD;
-            case MODIFY:
-                return MeterRequest.Type.MODIFY;
-            case REMOVE:
-                return MeterRequest.Type.REMOVE;
-            case UNRECOGNIZED:
-                log.warn("Unrecognized MeterRequest type gRPC message: {}", type);
-                return null;
-            default:
-                log.warn("Unrecognized MeterRequest type gRPC message: {}", type);
-                return null;
-        }
-    }
-
-    /**
-     * Translates gRPC MeterRequest to {@link MeterRequest}.
-     *
-     * @param meterRequest gRPC message
-     * @return {@link MeterRequest}
-     */
-    public static MeterRequest translate(MeterRequestProto meterRequest) {
-
-        DeviceId deviceid = DeviceId.deviceId(meterRequest.getDeviceId());
-        ApplicationId appId = translate(meterRequest.getApplicationId());
-        Meter.Unit unit = translate(meterRequest.getUnit());
-        boolean burst = meterRequest.getIsBurst();
-        Collection<Band> bands = translate(meterRequest.getBandsList());
-        MeterRequest.Type type = translate(meterRequest.getType());
-        if (type == MeterRequest.Type.ADD) {
-            return DefaultMeterRequest.builder()
-                    .forDevice(deviceid)
-                    .fromApp(appId)
-                    .withUnit(unit)
-                    .withBands(bands)
-                    .add();
-        } else {
-            return DefaultMeterRequest.builder()
-                    .forDevice(deviceid)
-                    .fromApp(appId)
-                    .withUnit(unit)
-                    .withBands(bands)
-                    .remove();
-        }
-    }
-
-    /**
-     * Translates {@link ApplicationId} to gRPC ApplicationId message.
-     *
-     * @param appId {@link ApplicationId}
-     * @return gRPC ApplicationId message
-     */
-    public static ApplicationIdProto translate(ApplicationId appId) {
-        return ApplicationIdProto.newBuilder()
-                .setId(appId.id())
-                .setName(appId.name())
-                .build();
-    }
-
-    /**
-     * Translates gRPC enum MeterUnit to ONOS enum.
-     *
-     * @param unit meterUnit in gRPC enum
-     * @return equivalent in ONOS enum
-     */
-    public static Meter.Unit translate(MeterUnitProto unit) {
-        switch (unit) {
-            case PKTS_PER_SEC:
-                return Meter.Unit.PKTS_PER_SEC;
-            case KB_PER_SEC:
-                return Meter.Unit.KB_PER_SEC;
-            case UNRECOGNIZED:
-                log.warn("Unrecognized MeterUnit gRPC message: {}", unit);
-                return null;
-            default:
-                log.warn("Unrecognized MeterUnit gRPC message: {}", unit);
-                return null;
-        }
-    }
-
-    /**
-     * Translates ONOS enum Meter.Unit Type to gRPC enum.
-     *
-     * @param unit Meter.Unit in ONOS enum
-     * @return equivalent in gRPC enum
-     */
-    public static MeterUnitProto translate(Meter.Unit unit) {
-        switch (unit) {
-            case PKTS_PER_SEC:
-                return org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterUnitProto.PKTS_PER_SEC;
-            case KB_PER_SEC:
-                return org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterUnitProto.KB_PER_SEC;
-            default:
-                log.warn("Unrecognized MeterUnit ONOS message: {}", unit);
-                return org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterUnitProto.UNRECOGNIZED;
-        }
-    }
-
-    /**
-     * Translates gRPC enum Band Type to ONOS enum.
-     *
-     * @param bandType BandType in gRPC enum
-     * @return equivalent in ONOS enum
-     */
-    public static Band.Type translate(BandTypeProto bandType) {
-        switch (bandType) {
-            case DROP:
-                return Band.Type.DROP;
-            case REMARK:
-                return Band.Type.REMARK;
-            case EXPERIMENTAL:
-                return Band.Type.EXPERIMENTAL;
-            case UNRECOGNIZED:
-                log.warn("Unrecognized BandType gRPC message: {}", bandType);
-                return null;
-            default:
-                log.warn("Unrecognized BandType gRPC message: {}", bandType);
-                return null;
-        }
-    }
-
-    /**
-     * Translates ONOS enum Band Type to gRPC enum.
-     *
-     * @param bandType BandType in ONOS enum
-     * @return equivalent in gRPC enum
-     */
-    public static BandTypeProto translate(Band.Type bandType) {
-        switch (bandType) {
-            case DROP:
-                return org.onosproject.grpc.net.meter.models.BandEnumsProto.BandTypeProto.DROP;
-            case REMARK:
-                return org.onosproject.grpc.net.meter.models.BandEnumsProto.BandTypeProto.REMARK;
-            case EXPERIMENTAL:
-                return org.onosproject.grpc.net.meter.models.BandEnumsProto.BandTypeProto.EXPERIMENTAL;
-            default:
-                log.warn("Unrecognized BandType ONOS message: {}", bandType);
-                return null;
-        }
-    }
-
-    /**
-     * Translates ONOS enum MeterState Type to gRPC enum.
-     *
-     * @param meterState MeterState in ONOS enum
-     * @return equivalent in gRPC enum
-     */
-    public static MeterStateProto translate(MeterState meterState) {
-        switch (meterState) {
-            case PENDING_ADD:
-                return org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterStateProto.PENDING_ADD;
-            case ADDED:
-                return org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterStateProto.ADDED;
-            case PENDING_REMOVE:
-                return org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterStateProto.PENDING_REMOVE;
-            case REMOVED:
-                return org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterStateProto.REMOVED;
-            default:
-                log.warn("Unrecognized MeterState ONOS message: {}", meterState);
-                return org.onosproject.grpc.net.meter.models.MeterEnumsProto.MeterStateProto.UNRECOGNIZED;
-        }
-    }
-
-    /**
      * Translates {@link Meter} to gRPC MeterCore message.
      *
      * @param meter {@link Meter}
@@ -270,20 +41,20 @@
     public static MeterProto translate(Meter meter) {
         return MeterProto.newBuilder()
                 .setDeviceId(meter.deviceId().toString())
-                .setApplicationId(translate(meter.appId()))
-                .setUnit(translate(meter.unit()))
+                .setApplicationId(ApplicationIdProtoTranslator.translate(meter.appId()))
+                .setUnit(MeterEnumsProtoTranslator.translate(meter.unit()))
                 .setIsBurst(meter.isBurst())
                 .addAllBands(meter.bands().stream()
                         .map(b -> BandProto.newBuilder()
                                 .setRate(b.rate())
                                 .setBurst(b.burst())
                                 .setDropPrecedence(b.dropPrecedence())
-                                .setType(translate(b.type()))
+                                .setType(BandProtoTranslator.translate(b.type()))
                                 .setPackets(b.packets())
                                 .setBytes(b.bytes())
                                 .build())
                         .collect(Collectors.toList()))
-                .setState(translate(meter.state()))
+                .setState(MeterEnumsProtoTranslator.translate(meter.state()))
                 .setLife(meter.life())
                 .setReferenceCount(meter.referenceCount())
                 .setPacketsSeen(meter.packetsSeen())
@@ -292,6 +63,5 @@
     }
 
     // Utility class not intended for instantiation.
-    private MeterProtoTranslator() {
-    }
+    private MeterProtoTranslator() {}
 }
diff --git a/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/MeterRequestProtoTranslator.java b/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/MeterRequestProtoTranslator.java
new file mode 100644
index 0000000..e63f35e
--- /dev/null
+++ b/incubator/protobuf/models/src/main/java/org/onosproject/incubator/protobuf/models/net/meter/MeterRequestProtoTranslator.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright 2017-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.incubator.protobuf.models.net.meter;
+
+import org.onosproject.core.ApplicationId;
+import org.onosproject.grpc.net.meter.models.MeterEnumsProto;
+import org.onosproject.grpc.net.meter.models.MeterRequestProtoOuterClass;
+import org.onosproject.incubator.protobuf.models.core.ApplicationIdProtoTranslator;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.meter.Band;
+import org.onosproject.net.meter.DefaultMeterRequest;
+import org.onosproject.net.meter.Meter;
+import org.onosproject.net.meter.MeterRequest;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collection;
+import java.util.Optional;
+
+/**
+ * gRPC message conversion related utilities for meter request service.
+ */
+public final class MeterRequestProtoTranslator {
+
+    private static final Logger log = LoggerFactory.getLogger(MeterRequestProtoTranslator.class);
+
+    /**
+     * Translates gRPC MeterRequestType to {@link MeterRequest.Type}.
+     *
+     * @param type gRPC message
+     * @return {@link MeterRequest.Type}
+     */
+    public static Optional<Object> translate(MeterEnumsProto.MeterRequestTypeProto type) {
+        switch (type) {
+            case ADD:
+                return Optional.of(MeterRequest.Type.ADD);
+            case MODIFY:
+                return Optional.of(MeterRequest.Type.MODIFY);
+            case REMOVE:
+                return Optional.of(MeterRequest.Type.REMOVE);
+            default:
+                log.warn("Unrecognized MeterRequest type gRPC message: {}", type);
+                return Optional.empty();
+        }
+    }
+
+    /**
+     * Translates gRPC MeterRequest to {@link MeterRequest}.
+     *
+     * @param meterRequest gRPC message
+     * @return {@link MeterRequest}
+     */
+    public static MeterRequest translate(MeterRequestProtoOuterClass.MeterRequestProto meterRequest) {
+
+        DeviceId deviceid = DeviceId.deviceId(meterRequest.getDeviceId());
+        ApplicationId appId = ApplicationIdProtoTranslator.translate(meterRequest.getApplicationId());
+        Meter.Unit unit = (Meter.Unit) MeterEnumsProtoTranslator.translate(meterRequest.getUnit()).get();
+        boolean burst = meterRequest.getIsBurst();
+        Collection<Band> bands = BandProtoTranslator.translate(meterRequest.getBandsList());
+        MeterRequest.Type type = (MeterRequest.Type) translate(meterRequest.getType()).get();
+        if (type == MeterRequest.Type.ADD) {
+            return DefaultMeterRequest.builder()
+                    .forDevice(deviceid)
+                    .fromApp(appId)
+                    .withUnit(unit)
+                    .withBands(bands)
+                    .add();
+        } else {
+            return DefaultMeterRequest.builder()
+                    .forDevice(deviceid)
+                    .fromApp(appId)
+                    .withUnit(unit)
+                    .withBands(bands)
+                    .remove();
+        }
+    }
+
+    // Utility class not intended for instantiation.
+    private MeterRequestProtoTranslator() {}
+}
diff --git a/incubator/protobuf/services/nb/src/main/java/org/onosproject/incubator/protobuf/services/nb/GrpcNbMeterService.java b/incubator/protobuf/services/nb/src/main/java/org/onosproject/incubator/protobuf/services/nb/GrpcNbMeterService.java
index cda8608..b62d0fb 100644
--- a/incubator/protobuf/services/nb/src/main/java/org/onosproject/incubator/protobuf/services/nb/GrpcNbMeterService.java
+++ b/incubator/protobuf/services/nb/src/main/java/org/onosproject/incubator/protobuf/services/nb/GrpcNbMeterService.java
@@ -18,6 +18,7 @@
 
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.onosproject.incubator.protobuf.models.net.meter.MeterRequestProtoTranslator;
 import org.onosproject.net.meter.MeterService;
 import org.onosproject.incubator.protobuf.models.net.meter.MeterProtoTranslator;
 
@@ -73,7 +74,7 @@
     public void submit(submitRequest request,
                        StreamObserver<submitReply> responseObserver) {
         submitReply.Builder replyBuilder = submitReply.newBuilder();
-        Meter meter = meterService.submit(MeterProtoTranslator.translate(request.getMeter()));
+        Meter meter = meterService.submit(MeterRequestProtoTranslator.translate(request.getMeter()));
         responseObserver.onNext(replyBuilder.setSubmitMeter(MeterProtoTranslator.translate(meter)).build());
         responseObserver.onCompleted();
     }
@@ -82,7 +83,7 @@
     public void withdraw(withdrawRequest request,
                          StreamObserver<withdrawReply> responseObserver) {
         withdrawReply.Builder replyBuilder = withdrawReply.newBuilder();
-        meterService.withdraw(MeterProtoTranslator.translate(request.getMeter()),
+        meterService.withdraw(MeterRequestProtoTranslator.translate(request.getMeter()),
                 MeterId.meterId(request.getMeterId()));
         responseObserver.onNext(replyBuilder.build());
         responseObserver.onCompleted();