Class ErrnoHandler

java.lang.Object

express.mvp.myra.transport.iouring.ErrnoHandler

public final class ErrnoHandler
extends Object

Utility class for handling Linux errno codes in io_uring operations.

This class maps native Linux error codes to meaningful Java exceptions with actionable recovery hints. It is essential for debugging io_uring operations where completion queue entries (CQEs) return negative errno values on failure.

Common Error Scenarios

Errno codes and their meanings

Errno	Name	Meaning	Recovery
11	EAGAIN	Resource temporarily unavailable	Retry operation
32	EPIPE	Broken pipe	Reconnect
104	ECONNRESET	Connection reset by peer	Reconnect
110	ETIMEDOUT	Connection timed out	Check network, retry
111	ECONNREFUSED	Connection refused	Verify server running

Usage Example

int result = LibUring.cqeGetRes(cqe);
if (result < 0) {
    if (ErrnoHandler.isRetryable(result)) {
        // Retry the operation
    } else if (ErrnoHandler.isConnectionLost(result)) {
        // Reconnect
    } else {
        throw ErrnoHandler.fromErrno(result, "send");
    }
}

See Also:

• LibUring.cqeGetRes(java.lang.foreign.MemorySegment)
• TransportException

Method Summary

Modifier and Type	Method	Description
static TransportException	fromErrno(int errno, String operation)	Creates a TransportException from an errno code with context.
static boolean	isConnectionLost(int errno)	Checks if the errno indicates the connection was lost.
static boolean	isConnectionRefused(int errno)	Checks if the errno indicates the connection was refused.
static boolean	isRetryable(int errno)	Checks if the errno indicates a retryable (transient) error.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

fromErrno

public static TransportException fromErrno(int errno,
 String operation)

Creates a TransportException from an errno code with context.

The exception message includes the operation name, error description, and actionable recovery hints for common errors.

Parameters:

errno - the Linux errno value (may be negative, will be converted to absolute)

operation - description of the failed operation (e.g., "send", "recv", "connect")

Returns:

a TransportException with descriptive message and recovery hints

isRetryable

public static boolean isRetryable(int errno)

Checks if the errno indicates a retryable (transient) error.

Retryable errors are temporary conditions that may succeed on retry, such as resource temporarily unavailable or operation in progress.

Parameters:

errno - the Linux errno value (may be negative)

Returns:

true if the operation should be retried

isConnectionLost

public static boolean isConnectionLost(int errno)

Checks if the errno indicates the connection was lost.

Connection loss requires reconnection to recover. This includes broken pipe, connection reset, and timeout errors.

Parameters:

errno - the Linux errno value (may be negative)

Returns:

true if the connection was lost and reconnection is needed

isConnectionRefused

public static boolean isConnectionRefused(int errno)

Checks if the errno indicates the connection was refused.

Connection refused means no service is listening on the target port. This typically requires verifying the server is running before retrying.

Parameters:

errno - the Linux errno value (may be negative)

Returns:

true if the connection was refused