[ONOS-5599] Store meter features into MeterStore

Change-Id: I22f7366b87cad6fc706b6ff7b0ccff1a0e85ad6a
diff --git a/core/api/src/main/java/org/onosproject/net/meter/MeterFeaturesKey.java b/core/api/src/main/java/org/onosproject/net/meter/MeterFeaturesKey.java
new file mode 100644
index 0000000..be49f96
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/meter/MeterFeaturesKey.java
@@ -0,0 +1,63 @@
+/*
+ * 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.net.meter;
+
+import org.onosproject.net.DeviceId;
+
+import java.util.Objects;
+
+/**
+ * A meter features key represents a meter features uniquely.
+ * Right now only deviceId is used but this class might be useful in
+ * virtualization in which a unique deviceId could have multiple features (guess).
+ */
+public final class MeterFeaturesKey {
+    private final DeviceId deviceId;
+
+    private MeterFeaturesKey(DeviceId deviceId) {
+        this.deviceId = deviceId;
+    }
+
+    public static MeterFeaturesKey key(DeviceId did) {
+        return new MeterFeaturesKey(did);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        MeterFeaturesKey mfk = (MeterFeaturesKey) obj;
+        return Objects.equals(deviceId, mfk.deviceId());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(deviceId);
+    }
+
+    @Override
+    public String toString() {
+        return "mfk@" + deviceId.toString();
+    }
+
+    public DeviceId deviceId() {
+        return deviceId;
+    }
+}