Pull up components() method as an abstract method

Change-Id: I80aecb74958b697fb18336bbe39853dd5cb67578
diff --git a/core/api/src/main/java/org/onosproject/net/newresource/ContinuousResourceId.java b/core/api/src/main/java/org/onosproject/net/newresource/ContinuousResourceId.java
index 4dadacf..fb213ef 100644
--- a/core/api/src/main/java/org/onosproject/net/newresource/ContinuousResourceId.java
+++ b/core/api/src/main/java/org/onosproject/net/newresource/ContinuousResourceId.java
@@ -45,6 +45,7 @@
         this.name = "";
     }
 
+    @Override
     ImmutableList<Object> components() {
         return components;
     }
diff --git a/core/api/src/main/java/org/onosproject/net/newresource/DiscreteResourceId.java b/core/api/src/main/java/org/onosproject/net/newresource/DiscreteResourceId.java
index 4b83344..3e5fc93 100644
--- a/core/api/src/main/java/org/onosproject/net/newresource/DiscreteResourceId.java
+++ b/core/api/src/main/java/org/onosproject/net/newresource/DiscreteResourceId.java
@@ -42,6 +42,7 @@
         this.components = ImmutableList.of();
     }
 
+    @Override
     ImmutableList<Object> components() {
         return components;
     }
diff --git a/core/api/src/main/java/org/onosproject/net/newresource/ResourceId.java b/core/api/src/main/java/org/onosproject/net/newresource/ResourceId.java
index 262cef2..1d92436 100644
--- a/core/api/src/main/java/org/onosproject/net/newresource/ResourceId.java
+++ b/core/api/src/main/java/org/onosproject/net/newresource/ResourceId.java
@@ -16,6 +16,7 @@
 package org.onosproject.net.newresource;
 
 import com.google.common.annotations.Beta;
+import com.google.common.collect.ImmutableList;
 
 import java.util.Optional;
 
@@ -27,6 +28,8 @@
 public abstract class ResourceId {
     static final DiscreteResourceId ROOT = new DiscreteResourceId();
 
+    abstract ImmutableList<Object> components();
+
     /**
      * Returns the parent resource ID of this instance.
      *