#7461 introducing WidgetItem interface for handling display on output…

… container items

kernel/base/src/main/java/com/twosigma/beakerx/easyform/EasyForm.java

@@ -34,6 +34,7 @@
 import com.twosigma.beakerx.widget.DisplayableWidget;
 import com.twosigma.beakerx.widget.ValueWidget;
 import com.twosigma.beakerx.widget.Widget;
+import com.twosigma.beakerx.widget.WidgetItem;
 import org.apache.commons.lang3.StringUtils;
 
 import java.util.Collection;
@@ -45,7 +46,7 @@
 import java.util.stream.Collectors;
 
 @SuppressWarnings("unchecked")
-public class EasyForm extends ObservableMap<String, Object> implements DisplayableWidget {
+public class EasyForm extends ObservableMap<String, Object> implements DisplayableWidget, WidgetItem {
 
   public static final Integer HORIZONTAL = 1;
   public static final Integer VERTICAL = 2;
@@ -387,4 +388,8 @@ public void display() {
     this.getView().display();
   }
 
+  @Override
+  public Widget asWidget() {
+    return getView();
+  }
 }

kernel/base/src/main/java/com/twosigma/beakerx/jvm/object/OutputContainerLayoutManager.java

@@ -16,11 +16,11 @@
 package com.twosigma.beakerx.jvm.object;
 
 import com.twosigma.beakerx.MIMEContainerFactory;
-import com.twosigma.beakerx.easyform.EasyForm;
 import com.twosigma.beakerx.mimetype.MIMEContainer;
 import com.twosigma.beakerx.widget.HTML;
 import com.twosigma.beakerx.widget.HTMLPre;
 import com.twosigma.beakerx.widget.Widget;
+import com.twosigma.beakerx.widget.WidgetItem;
 
 import java.util.List;
 import java.util.Optional;
@@ -55,16 +55,13 @@ private Optional<Widget> toWidget(Object item) {
     if (item == null) {
       return handleNull();
     }
-    if (item instanceof EasyForm) {
-      return of(((EasyForm) item).getView());
+    if (item instanceof WidgetItem) {
+      return of(((WidgetItem) item).asWidget());
     }
     Widget widget = MIMEContainerFactory.getTableDisplay(item);
     if (widget != null) {
       return of(widget);
     }
-    if (item instanceof Widget) {
-      return of((Widget) item);
-    }
     if (item instanceof MIMEContainer) {
       return of(createHTML(((MIMEContainer) item).getData().toString()));
     }

kernel/base/src/main/java/com/twosigma/beakerx/widget/Widget.java

@@ -15,18 +15,18 @@
  */
 package com.twosigma.beakerx.widget;
 
+import com.twosigma.beakerx.kernel.KernelManager;
+import com.twosigma.beakerx.kernel.comm.Comm;
+import com.twosigma.beakerx.kernel.comm.TargetNamesEnum;
+import com.twosigma.beakerx.message.Message;
+
 import java.io.Serializable;
 import java.util.HashMap;
 
 import static com.twosigma.beakerx.handler.KernelHandlerWrapper.wrapBusyIdle;
 import static com.twosigma.beakerx.kernel.msg.JupyterMessages.DISPLAY_DATA;
 
-import com.twosigma.beakerx.kernel.KernelManager;
-import com.twosigma.beakerx.kernel.comm.Comm;
-import com.twosigma.beakerx.kernel.comm.TargetNamesEnum;
-import com.twosigma.beakerx.message.Message;
-
-public abstract class Widget implements CommFunctionality, DisplayableWidget {
+public abstract class Widget implements CommFunctionality, DisplayableWidget, WidgetItem {
 
   public static final String APPLICATION_VND_JUPYTER_WIDGET_VIEW_JSON = "application/vnd.jupyter.widget-view+json";
   public static final String MODEL_ID = "model_id";
@@ -179,4 +179,9 @@ public interface WidgetDisplayMethodStrategy {
     void display(Widget widget);
   }
 
+  @Override
+  public Widget asWidget() {
+    return this;
+  }
+
 }

kernel/base/src/main/java/com/twosigma/beakerx/widget/WidgetItem.java

@@ -0,0 +1,23 @@
+/*
+ *  Copyright 2018 TWO SIGMA OPEN SOURCE, LLC
+ *
+ *  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 com.twosigma.beakerx.widget;
+
+import com.twosigma.beakerx.widget.Widget;
+
+public interface WidgetItem {
+
+    Widget asWidget();
+}