emptyGenerator = new EmptyGenerator();

        // Test adding conditions - this should work without container
        emptyGenerator.addCondition("field1", "pattern1");
        emptyGenerator.addCondition("field1", "pattern2");
        emptyGenerator.addCondition("field2", "pattern.*");

        // We can't test isTarget properly without container,
        // but we can verify conditions are added
        assertNotNull(emptyGenerator);

        Pattern[] patterns = (Pattern[]) propMap.get(CRAWLER_METADATA_CONTENT_EXCLUDES);
        if (patterns == null) {
            patterns = split(getCrawlerMetadataContentExcludes(), ",")
                    .get(stream -> stream.filter(StringUtil::isNotBlank).map(Pattern::compile).toArray(n -> new Pattern[n]));
            propMap.put(CRAWLER_METADATA_CONTENT_EXCLUDES, patterns);
        }

    }

    /**
     * Converts a GSA URL pattern into a regular expression pattern suitable for Fess.
     * Handles various GSA pattern formats including regexp, contains, and URL-based patterns.
     *
     * @param s the input GSA pattern string
     * @return a regular expression pattern string, or empty string for comments/invalid patterns
     */
    protected String getFilterPath(final String s) {

    /**
     * Cache for client rules mapping client names to their corresponding URL patterns.
     * This cache improves performance by avoiding repeated parsing of client configuration rules.
     * The key is the rule string, and the value is a pair containing the client name and compiled pattern.
     */
    protected ConcurrentHashMap<String, Pair<String, Pattern>> clientRuleCache = new ConcurrentHashMap<>();

    /**

### Key Architectural Patterns
- **Factory Pattern** - `BeanDescFactory` for creating bean descriptors, `ParameterizedClassDescFactory` for generic type handling
- **Builder Pattern** - `CopyOptions` for configuring bean copying operations with fluent API
- **Adapter Pattern** - Logging adapters (`JclLoggerAdapter`, `JulLoggerAdapter`) for different logging frameworks

        assertFalse(validator.isValid("* * * *", context));
    }

    // Test common valid cron patterns that are likely to work
    public void test_basicValidCronExpressions() {
        final ConstraintValidatorContext context = null;

        // Test basic patterns that should be valid
        String[] potentiallyValidCrons = { "0 0 * * * ?", // Every hour
                "0 */15 * * * ?", // Every 15 minutes

                final Pattern pattern = Pattern.compile(value);
                paramMap.put(URL_EXCLUDE_PATTERN, pattern);
                if (logger.isDebugEnabled()) {
                    logger.debug("Using exclude pattern: {}", pattern);
                }
            }
            if (paramMap.get(URL_EXCLUDE_PATTERN) instanceof final Pattern pattern) {
                if (pattern.matcher(url).matches()) {

  }

  static CommonPattern compilePattern(String pattern) {
    Preconditions.checkNotNull(pattern);
    return patternCompiler.compile(pattern);
  }

  static boolean patternCompilerIsPcreLike() {
    return patternCompiler.isPcreLike();
  }

  private static PatternCompiler loadPatternCompiler() {
    // We want the JDK Pattern compiler:
    // - under Android (where it hurts startup performance)

    /** Format identifier for PDF date parsing */
    private static final String PDF_DATE = "pdf_date";

    /** Regular expression pattern for matching email addresses */
    private static final Pattern EMAIL_ADDRESS_PATTERN =
            Pattern.compile("[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,6}", Pattern.CASE_INSENSITIVE);

    /**
     * Cache for storing resource file modification timestamps to enable cache busting.

        // Pattern uses Object (identity) equality, so we have to reach
        // inside to compare individual fields.
        return Objects.equals(pattern.pattern(), that.pattern.pattern())
            && pattern.flags() == that.pattern.flags();
      }
      return false;
    }

    @Override
    public String toString() {
      String patternString =