* {@link MemoryDataHelper} to store and manage the URL patterns in memory.
 *
 */
public class UrlFilterServiceImpl implements UrlFilterService {

    /**
     * Creates a new UrlFilterServiceImpl instance.
     */
    public UrlFilterServiceImpl() {
        // NOP
    }

    /**
     * The memory data helper.
     */
    @Resource
    protected MemoryDataHelper dataHelper;

    /*

 - ConnectionAcquired
 - ... Standard Events...
 - ResponseBodyEnd _(0 bytes)_
 - **CacheHit**
 - ConnectionReleased
 - CallEnd
 
## Cache directory

The cache directory must be exclusively owned by a single instance.

Deleting the cache when it is no longer needed can be done.  However this may delete the purpose of the cache
which is designed to persist between app restarts.

```kotlin
cache.delete()
```
 

        assertSame(range, VersionRange.createFromVersionSpec("[1.0,1.2]")); // same instance from spec cache

        VersionRange spec = VersionRange.createFromVersionSpec("1.0");
        assertSame(spec, VersionRange.createFromVersionSpec("1.0")); // same instance from spec cache
        List<Restriction> restrictions = spec.getRestrictions();

        ComparableVersion c1 = new ComparableVersion("1");
        c1.parseVersion("2");

        Comparable<?> c2 = newComparable("2");

        assertEquals(c1, c2, "reused instance should be equivalent to new instance");
    }

    /**
     * Test <a href="https://issues.apache.org/jira/browse/MNG-7644">MNG-7644</a> edge cases
     * 1.0.0.RC1 &lt; 1.0.0-RC2 and more generally:

    //                                                                           =========
    private static final PathMappingDbm _instance = new PathMappingDbm();

    private PathMappingDbm() {
    }

    public static PathMappingDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final FavoriteLogDbm _instance = new FavoriteLogDbm();

    private FavoriteLogDbm() {
    }

    public static FavoriteLogDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final ThumbnailQueueDbm _instance = new ThumbnailQueueDbm();

    private ThumbnailQueueDbm() {
    }

    public static ThumbnailQueueDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

        // ## Act ##
        final CurlRequest request1 = Curl.get("http://example.com");
        final CurlRequest request2 = Curl.get("http://example.com");

        // ## Assert ##
        assertNotNull(request1);
        assertNotNull(request2);
        assertTrue("Factory methods should return different instances", request1 != request2);
    }

    /*

    //                                                                           =========
    private static final JobLogDbm _instance = new JobLogDbm();

    private JobLogDbm() {
    }

    public static JobLogDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

 * retrieval, storage, deletion, and search functionality.
 */
public class RelatedContentService extends FessAppService {

    /**
     * Default constructor.
     * Creates a new instance of RelatedContentService.
     */
    public RelatedContentService() {
        super();
    }

    /**
     * Behavior class for RelatedContent entity operations.