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 javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  
  import org.fest.swing.annotation.RunsInCurrentThread;
  
  /**
   * Finds the focus owner using the roots of a {@code Component} hierarchy.
   * 
   * @author Alex Ruiz
   */
  class HierarchyBasedFocusOwnerFinder implements FocusOwnerFinderStrategy {
    private final ContainerFocusOwnerFinder delegate;
    private final HierarchyRootsSource rootsSource;
  
    HierarchyBasedFocusOwnerFinder() {
      this(new ContainerFocusOwnerFinder(), new HierarchyRootsSource());
    }
  
    HierarchyBasedFocusOwnerFinder(@Nonnull ContainerFocusOwnerFinder newDelegate,
        @Nonnull HierarchyRootsSource newRootsSource) {
      delegate = newDelegate;
      rootsSource = newRootsSource;
    }
  
    @Override
    @RunsInCurrentThread
    public @Nullable Component focusOwner() {
      for (Container c : rootsSource.existingHierarchyRoots()) {
        Component focus = delegate.focusOwnerOf(c);
        if (focus != null) {
          return focus;
        }
      }
      return null;
    }
  }
  