* governing permissions and limitations under the License.
 */
package org.codelibs.fess.ds.callback;

import static org.codelibs.core.stream.StreamUtil.stream;

import java.util.ArrayList;
import java.util.Deque;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.LinkedBlockingQueue;