SimpleWidgetPanel.java

/*
 * Copyright 2014-2016 CyberVision, Inc.
 *
 * 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.kaaproject.kaa.server.admin.client.layout;

import com.google.gwt.user.client.ui.AcceptsOneWidget;
import com.google.gwt.user.client.ui.IsWidget;
import com.google.gwt.user.client.ui.LayoutPanel;
import com.google.gwt.user.client.ui.Widget;

public class SimpleWidgetPanel extends LayoutPanel implements AcceptsOneWidget {

  private Widget widget;

  @Override
  public void setWidget(IsWidget widget) {
    setOneWidget(asWidgetOrNull(widget));
  }

  private void setOneWidget(Widget widget) {
    // validate
    if (widget == this.widget) {
      return;
    }

    // remove the old widget
    if (this.widget != null) {
      super.remove(this.widget);
    }

    // logical attach
    this.widget = widget;

    if (widget != null) {
      super.add(widget);
    }
    forceLayout();
  }
}