* @param buf the StringBuilder to append to
     * @param libDir the directory containing JAR files
     * @param basePath the base path to prepend to JAR file names
     */
    protected void appendJarFile(final String cpSeparator, final StringBuilder buf, final File libDir, final String basePath) {
        final File[] jarFiles = libDir.listFiles((FilenameFilter) (dir, name) -> name.toLowerCase().endsWith(".jar"));

        /**
         * Fess configuration for settings.
         */
        protected final FessConfig fessConfig;

        FilePurgeVisitor(final Path basePath, final String imageExtention, final long expiry) {
            this.basePath = basePath;
            this.imageExtention = imageExtention;
            this.expiry = expiry;
            fessConfig = ComponentUtil.getFessConfig();

        try {
            // Measure timing for differences at different positions
            long timeStart = measureEqualsTime(baseAuth, startAuth, TIMING_ITERATIONS);
            long timeMiddle = measureEqualsTime(baseAuth, middleAuth, TIMING_ITERATIONS);
            long timeEnd = measureEqualsTime(baseAuth, endAuth, TIMING_ITERATIONS);

            // Calculate relative timing differences