Parse externalComponent options

lib/android/app/src/main/java/com/reactnativenavigation/parse/ExternalComponent.java

+package com.reactnativenavigation.parse;
+
+import com.reactnativenavigation.parse.params.NullText;
+import com.reactnativenavigation.parse.params.Text;
+import com.reactnativenavigation.parse.parsers.TextParser;
+
+import org.json.JSONObject;
+
+public class ExternalComponent {
+
+    public Text classCreator = new NullText();
+
+    public static ExternalComponent parse(JSONObject json) {
+        ExternalComponent options = new ExternalComponent();
+        if (json == null) {
+            return options;
+        }
+
+        options.classCreator = TextParser.parse(json, "classCreator");
+        if (!options.classCreator.hasValue()) {
+            throw new RuntimeException("ExternalClass must declare classCreator - a fully qualified method name");
+        }
+
+        return options;
+    }
+
+    public void mergeWith(ExternalComponent other) {
+        if (other.classCreator.hasValue()) {
+            classCreator = other.classCreator;
+        }
+    }
+
+    public void mergeWithDefault(ExternalComponent defaultOptions) {
+        if (!classCreator.hasValue()) {
+            classCreator = defaultOptions.classCreator;
+        }
+    }
+}

lib/android/app/src/main/java/com/reactnativenavigation/parse/Options.java

         result.fabOptions = FabOptions.parse(json.optJSONObject("fab"));
         result.animationsOptions = AnimationsOptions.parse(json.optJSONObject("animations"));
         result.sideMenuRootOptions = SideMenuRootOptions.parse(json.optJSONObject("sideMenu"));
+        result.externalComponent = ExternalComponent.parse(json.optJSONObject("externalComponent"));
 
         return result.withDefaultOptions(defaultOptions);
     }
     @NonNull public FabOptions fabOptions = new FabOptions();
     @NonNull public AnimationsOptions animationsOptions = new AnimationsOptions();
     @NonNull public SideMenuRootOptions sideMenuRootOptions = new SideMenuRootOptions();
+    @NonNull public ExternalComponent externalComponent = new ExternalComponent();
 
     void setTopTabIndex(int i) {
         topTabOptions.tabIndex = i;
         result.fabOptions.mergeWith(fabOptions);
         result.animationsOptions.mergeWith(animationsOptions);
         result.sideMenuRootOptions.mergeWith(sideMenuRootOptions);
+        result.externalComponent.mergeWith(externalComponent);
         return result;
     }
 
         result.fabOptions.mergeWith(other.fabOptions);
         result.animationsOptions.mergeWith(other.animationsOptions);
         result.sideMenuRootOptions.mergeWith(other.sideMenuRootOptions);
+        result.externalComponent.mergeWith(other.externalComponent);
         return result;
     }
 
         fabOptions.mergeWithDefault(other.fabOptions);
         animationsOptions.mergeWithDefault(other.animationsOptions);
         sideMenuRootOptions.mergeWithDefault(other.sideMenuRootOptions);
+        externalComponent.mergeWithDefault(other.externalComponent);
         return this;
     }
 

lib/android/app/src/test/java/com/reactnativenavigation/parse/OptionsTest.java

     private static final String BOTTOM_TABS_BADGE = "3";
     private static final String BOTTOM_TABS_CURRENT_TAB_ID = "ComponentId";
     private static final Number BOTTOM_TABS_CURRENT_TAB_INDEX = new Number(1);
+    private static final String EXTERNAL_CLASS_CREATOR = "com.rnn.creators.Creator.createFragment";
     private TypefaceLoader mockLoader;
 
     @Override
         JSONObject json = new JSONObject()
                 .put("topBar", createTopBar(TOP_BAR_VISIBLE.get()))
                 .put("fab", createFab())
+                .put("externalComponent", createExternalComponent())
                 .put("bottomTabs", createBottomTabs());
         Options result = Options.parse(mockLoader, json);
         assertResult(result);
         assertThat(result.fabOptions.hideOnScroll.get()).isEqualTo(FAB_HIDE_ON_SCROLL);
         assertThat(result.fabOptions.alignVertically.get()).isEqualTo(FAB_ALIGN_VERTICALLY);
         assertThat(result.fabOptions.alignHorizontally.get()).isEqualTo(FAB_ALIGN_HORIZONTALLY);
+        assertThat(result.externalComponent.classCreator.get()).isEqualTo(EXTERNAL_CLASS_CREATOR);
     }
 
     @NonNull
                 .put("visible", FAB_VISIBLE);
     }
 
+    private JSONObject createExternalComponent() throws JSONException {
+        return new JSONObject()
+                .put("classCreator", EXTERNAL_CLASS_CREATOR);
+    }
+
     @NonNull
     private JSONObject createOtherFab() throws JSONException {
         return new JSONObject()
                 .put("tabBadge", BOTTOM_TABS_BADGE);
     }
 
+    private JSONObject createOtherExternalClass() {
+        return new JSONObject();
+    }
+
     @Test
     public void mergeDoesNotMutate() throws Exception {
         JSONObject json1 = new JSONObject();
 
     @Test
     public void mergeDefaultOptions() throws Exception {
-        JSONObject json = new JSONObject();
-        json.put("topBar", createTopBar(TOP_BAR_VISIBLE.get()));
-        json.put("fab", createFab());
-        json.put("bottomTabs", createBottomTabs());
+        JSONObject json = new JSONObject()
+                .put("topBar", createTopBar(TOP_BAR_VISIBLE.get()))
+                .put("fab", createFab())
+                .put("bottomTabs", createBottomTabs())
+                .put("externalComponent", createExternalComponent());
         Options defaultOptions = Options.parse(mockLoader, json);
         Options options = new Options();
 
         JSONObject defaultJson = new JSONObject()
                 .put("topBar", createOtherTopBar())
                 .put("fab", createOtherFab())
-                .put("bottomTabs", createOtherBottomTabs());
+                .put("bottomTabs", createOtherBottomTabs())
+                .put("externalComponent", createExternalComponent());
         Options defaultOptions = Options.parse(mockLoader, defaultJson);
 
         JSONObject json = new JSONObject()