content: /*
   * Created on May 31, 2009
   * 
   * 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.
   * 
   * Copyright @2009-2013 the original author or authors.
   */
  package org.fest.swing.core;
  
  import java.awt.Component;
  import java.awt.Container;
  import java.awt.Window;
  
  import javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  
  import org.fest.swing.annotation.RunsInCurrentThread;
  
  /**
   * Finds the focus owner of an AWT or Swing {@code Container}.
   * 
   * @author Alex Ruiz
   */
  class ContainerFocusOwnerFinder {
    @RunsInCurrentThread
    @Nullable Component focusOwnerOf(@Nullable Container c) {
      if (!(c instanceof Window)) {
        return null;
      }
      return focusOwnerOf((Window) c);
    }
  
    @RunsInCurrentThread
    private @Nullable Component focusOwnerOf(@Nonnull Window w) {
      if (!w.isShowing()) {
        return null;
      }
      Component focus = w.getFocusOwner();
      if (focus != null) {
        return focus;
      }
      for (Window o : w.getOwnedWindows()) {
        focus = o.getFocusOwner();
        if (focus != null) {
          return focus;
        }
      }
      return null;
    }
  }
  