/**
 * Abstract base class for thumbnail generators.
 * Provides common functionality for thumbnail generation implementations.
 */
public abstract class BaseThumbnailGenerator implements ThumbnailGenerator {
    private static final Logger logger = LogManager.getLogger(BaseThumbnailGenerator.class);

    /** Map of conditions for thumbnail generation. */
    protected final Map<String, String> conditionMap = new HashMap<>();

    protected final List<ThumbnailGenerator> generatorList = new ArrayList<>();

    /**
     * Queue for thumbnail generation tasks containing URL, content, and path tuples.
     */
    protected BlockingQueue<Tuple3<String, String, String>> thumbnailTaskQueue;

    /**
     * Flag indicating whether thumbnail generation is currently in progress.
     */
    protected volatile boolean generating;

    private Thread thumbnailQueueThread;

     * This implementation is empty as no cleanup is required.
     */
    @Override
    public void destroy() {
    }

    /**
     * Creates a thumbnail generation task for the specified document.
     *
     * @param path the file path or URL of the document
     * @param docMap the document metadata map containing field values

 */
public class CommandGenerator extends BaseThumbnailGenerator {
    private static final Logger logger = LogManager.getLogger(CommandGenerator.class);

    /** List of command strings to execute for thumbnail generation. */
    protected List<String> commandList;

    /** Timeout for command execution in milliseconds. */
    protected long commandTimeout = 30 * 1000L;// 30sec

 */
public class GenerateThumbnailJob extends ExecJob {
    /** Logger for this class. */
    static final Logger logger = LogManager.getLogger(GenerateThumbnailJob.class);

    /** Number of threads to use for thumbnail generation. */
    protected int numOfThreads = 1;

    /** Flag indicating whether to perform cleanup operations. */
    protected boolean cleanup = false;

    /**
     * Default constructor for the GenerateThumbnailJob.

  }

  /**
   * Returns a {@link Collection} of all the permutations of the specified {@link Iterable}.
   *
   * <p><i>Notes:</i> This is an implementation of the algorithm for Lexicographical Permutations
   * Generation, described in Knuth's "The Art of Computer Programming", Volume 4, Chapter 7,
   * Section 7.2.1.2. The iteration order follows the lexicographical order. This means that the

└── LeaseManager.java            - Central lease management
```

#### 1.2 Implementation Tasks
- [ ] Define lease state constants (SMB2_LEASE_READ, SMB2_LEASE_HANDLE, SMB2_LEASE_WRITE)
- [ ] Implement lease key generation and management
- [ ] Add lease context to Create request/response
- [ ] Implement lease break notification handling
- [ ] Modify SmbFile to support lease-based caching
- [ ] Add lease upgrade/downgrade logic

- **XML Processing** (`org.codelibs.core.xml`) - XML DOM utilities, SAX parser helpers, and schema validation support
- **SQL Utilities** (`org.codelibs.core.sql`) - JDBC helper methods for result sets, prepared statements, and connection management
- **Network & I/O** (`org.codelibs.core.net`, `org.codelibs.core.nio`) - URL utilities, UUID generation, MIME type detection, and NIO channel operations

    /** Helper for performing search operations and managing search requests. */
    @Resource
    protected SearchHelper searchHelper;

    /** Manager for handling thumbnail generation and display. */
    @Resource
    protected ThumbnailManager thumbnailManager;

    /** Helper for managing label types and label-based filtering. */
    @Resource
    protected LabelTypeHelper labelTypeHelper;

     * When enabled, a login link is shown to unauthenticated users.
     */
    @Size(max = 10)
    public String loginLink;

    /**
     * Enable or disable thumbnail generation for documents.
     * When enabled, thumbnails are generated for supported file types.
     */
    @Size(max = 10)
    public String thumbnail;

    /**