content: /*
   * Created on Mar 30, 2008
   * 
   * 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 @2008-2013 the original author or authors.
   */
  package org.fest.swing.core;
  
  import static org.fest.swing.edt.GuiActionRunner.execute;
  import static org.fest.util.Lists.newArrayList;
  import static org.fest.util.Preconditions.checkNotNull;
  
  import java.awt.Component;
  import java.util.List;
  
  import javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  
  import org.fest.swing.annotation.RunsInCurrentThread;
  import org.fest.swing.annotation.RunsInEDT;
  import org.fest.swing.edt.GuiQuery;
  import org.fest.util.VisibleForTesting;
  
  /**
   * Finds the AWT or Swing {@code Component} owning the input focus.
   * 
   * @author Yvonne Wang
   * @author Alex Ruiz
   */
  public final class FocusOwnerFinder {
    private static final List<FocusOwnerFinderStrategy> STRATEGIES = newArrayList();
  
    static {
      initializeStrategies();
    }
  
    @VisibleForTesting
    static void initializeStrategies() {
      replaceStrategiesWith(new ReflectionBasedFocusOwnerFinder(), new HierarchyBasedFocusOwnerFinder());
    }
  
    @VisibleForTesting
    static void replaceStrategiesWith(@Nonnull FocusOwnerFinderStrategy... strategies) {
      STRATEGIES.clear();
      STRATEGIES.addAll(newArrayList(strategies));
    }
  
    @VisibleForTesting
    static @Nonnull List<FocusOwnerFinderStrategy> strategies() {
      return newArrayList(STRATEGIES);
    }
  
    /**
     * @return the focus owner. This method is executed in the event dispatch thread (EDT.)
     */
    @RunsInEDT
    public static @Nullable Component inEdtFocusOwner() {
      return execute(new GuiQuery<Component>() {
        @Override
        protected @Nullable Component executeInEDT() {
          return focusOwner();
        }
      });
    }
  
    /**
     * <p>
     * Returns the focus owner.
     * </p>
     * 
     * <p>
     * <b>Note:</b> This method is accessed in the current executing thread. Such thread may or may not be the event
     * dispatch thread (EDT.) Client code must call this method from the EDT.
     * </p>
     * 
     * @return the focus owner.
     */
    @RunsInCurrentThread
    public static @Nullable Component focusOwner() {
      for (FocusOwnerFinderStrategy strategy : STRATEGIES) {
        Component focusOwner = focusOwnerFrom(checkNotNull(strategy));
        if (focusOwner != null) {
          return focusOwner;
        }
      }
      return null;
    }
  
    private static @Nullable Component focusOwnerFrom(@Nonnull FocusOwnerFinderStrategy strategy) {
      try {
        return strategy.focusOwner();
      } catch (Exception e) {
        return null;
      }
    }
  
    private FocusOwnerFinder() {}
  }
  