int count = 1;
        final ExecutorService executorService = Executors.newFixedThreadPool(options.numOfThreads);
        try {
            while (count != 0) {
                count = ComponentUtil.getThumbnailManager().generate(executorService, options.cleanup);
                totalCount += count;
            }
            executorService.shutdown();
            executorService.awaitTermination(60, TimeUnit.SECONDS);

            this.windowSize = windowSize;
        }
    }

    @Override
    @PreDestroy
    public void close() throws Exception {
        if (executorService != null) {
            try {
                executorService.shutdown();
                executorService.awaitTermination(60, TimeUnit.SECONDS);
            } catch (final InterruptedException e) {
                if (logger.isDebugEnabled()) {

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;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

import org.apache.logging.log4j.LogManager;

        }
        final ThumbnailQueueBhv thumbnailQueueBhv = ComponentUtil.getComponent(ThumbnailQueueBhv.class);
        thumbnailQueueBhv.batchInsert(list);
    }

    public int generate(final ExecutorService executorService, final boolean cleanup) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final List<String> idList = new ArrayList<>();

import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

import javax.annotation.PostConstruct;