return LaRequestUtil.getOptionalRequest().map(req -> (T) req.getAttribute(name)).orElse(null);
    }

    /**
     * Sets an error in the current request with the specified status code and message.
     *
     * @param statusCode The HTTP status code
     * @param message The error message
     */
    public static void setError(final int statusCode, final String message) {

        this.completed = true;
    }

    /**
     * Mark request as failed with error
     *
     * @param error exception that caused the failure
     */
    public void markFailed(Exception error) {
        this.error = error;
        this.completed = true;
    }

    /**
     * Get error if request failed
     *
     * @return exception if failed, null if successful
     */

    //                                                                      ==============
    /**
     * Displays the not found error page.
     *
     * @param form the error form containing error information
     * @return HTML response for the not found error page
     */
    @Execute
    public HtmlResponse index(final ErrorForm form) {
        return asHtml(virtualHost(path_Error_NotFoundJsp));
    }

    // Getters for all statistics...
}
```

## 9. Error Handling and Fallback

### 9.1 RDMA Error Recovery
```java
public class RdmaErrorHandler {
    public void handleRdmaError(RdmaConnection connection, Exception error) {
        log.warn("RDMA error occurred: {}", error.getMessage());
        
        if (isRecoverableError(error)) {
            // Attempt to recover connection
            try {

     *
     * @throws IOException if an I/O error occurs (not thrown in this implementation)
     */
    @Override
    public void close() throws IOException {
        // inputStream.close();
    }

    /**
     * Returns the number of bytes that can be read from this input stream without blocking.
     *
     * @return the number of bytes available
     * @throws IOException if an I/O error occurs
     */
    @Override

 * to create an exception instance with a message, a cause, or both.
 *
 * <p>Usage examples:</p>
 * <pre>
 * throw new SuggesterException("An error occurred");
 * throw new SuggesterException(new IOException("IO error"));
 * throw new SuggesterException("An error occurred", new IOException("IO error"));
 * </pre>
 *
 * @see RuntimeException
 */
public class SuggesterException extends RuntimeException {

     * @throws IOException if an I/O error occurs
     */
    public PacDataInputStream(final InputStream in) throws IOException {
        this.dis = new DataInputStream(in);
        this.size = in.available();
    }

    /**
     * Aligns the stream position to the specified boundary.
     * @param mask the alignment mask (typically 2, 4, or 8)
     * @throws IOException if an I/O error occurs
     */

      immediateFailedFuture(OTHER_THROWABLE);
  static final Error ERROR = new Error("mymessage");
  static final Future<String> FAILED_FUTURE_ERROR = immediateFailedFuture(ERROR);
  static final Future<String> RUNTIME_EXCEPTION_FUTURE =
      UncheckedThrowingFuture.throwingRuntimeException(RUNTIME_EXCEPTION);
  static final Future<String> ERROR_FUTURE = UncheckedThrowingFuture.throwingError(ERROR);

 */
package org.codelibs.fess.exception;

import org.apache.lucene.queryparser.classic.ParseException;

/**
 * Exception thrown when a query parsing error occurs.
 * This exception wraps Lucene's ParseException to provide consistent error handling
 * within the Fess search framework.
 *
 */
public class QueryParseException extends FessSystemException {

    /** Serial version UID for serialization compatibility */

            } catch (InterruptedException ignore) {}
            deferred.reject(new Exception());
        });
        th.start();

        final CountDownLatch latch = new CountDownLatch(1);
        deferred.promise().error(error -> latch.countDown());
        assertTrue(latch.await(10, TimeUnit.SECONDS));
    }

    @Test
    public void test_doneAfterReject() throws Exception {