protected T instance;

        protected Consumer<T> destroyer;

        protected ComponentHolder(final T instance, final Consumer<T> destroyer) {
            this.instance = instance;
            this.destroyer = destroyer;
        }

        protected T get() {
            return instance;
        }

        protected void destroy() {

    }

    @Override
    public boolean available() {
        return SingletonLaContainerFactory.hasContainer();
    }

    @Override
    public void destroy() {
        SingletonLaContainerFactory.destroy();
    }

public class WebApiFilter implements Filter {

    @Override
    public void init(final FilterConfig filterConfig) throws ServletException {
        // nothing
    }

    @Override
    public void destroy() {
        // nothing
    }

    @Override
    public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain)
            throws IOException, ServletException {

        }
        final String commandDestroyTimeoutStr = fessConfig.getSystemProperty("thumbnail.command.destroy.timeout");
        if (commandDestroyTimeoutStr != null) {
            commandDestroyTimeout = Long.valueOf(commandDestroyTimeoutStr);
        }
    }

    @Override
    public void destroy() {
        destoryTimer.cancel();
        destoryTimer = null;
    }

    @Override

public interface ThumbnailGenerator {

    String getName();

    boolean generate(String thumbnailId, File outputFile);

    boolean isTarget(Map<String, Object> docMap);

    boolean isAvailable();

    void destroy();

    Tuple3<String, String, String> createTask(String path, Map<String, Object> docMap);

public class EmptyGenerator extends BaseThumbnailGenerator {

    @Override
    public boolean generate(final String thumbnailId, final File outputFile) {
        return false;
    }

    @Override
    public void destroy() {
        // nothing
    }

import org.codelibs.core.lang.StringUtil;

/**
 * @author shinsuke
 *
 */
public interface CrawlerContainer {

    <T> T getComponent(String name);

    boolean available();

    void destroy();

    default void initialize() {
        final StringBuilder buf = new StringBuilder(100);
        final String value = System.getProperty("java.protocol.handler.pkgs");
        if (StringUtil.isEmpty(value)) {

    protected final ConcurrentHashMap<String, JobProcess> runningProcessMap = new ConcurrentHashMap<>();

    protected int processDestroyTimeout = 10;

    @PreDestroy
    public void destroy() {
        for (final String sessionId : runningProcessMap.keySet()) {
            if (logger.isInfoEnabled()) {
                logger.info("Stopping process {}", sessionId);
            }

                } catch (final Exception e) {
                    // ignore
                }
            }
            if (currentProcess != null) {
                try {
                    currentProcess.destroy();
                } catch (final Exception e) {
                    // ignore
                }
            }
            currentProcess = null;

        }
    }

    @Override
    public void rollback() {
        for (final MultipartFormFile formFile : elementsFile.values()) {
            formFile.destroy();
        }
    }

    // ===================================================================================
    //                                                                            Add Text