org.apache.juneau.rest

Interface RestLogger

All Known Subinterfaces:

RestLogger.Null

All Known Implementing Classes:

BasicRestLogger, NoOpRestLogger

public interface RestLogger

Logging utility class.

See Also:

• RestContext.REST_logger
• Overview > juneau-rest-server > Logging and Error Handling

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	RestLogger.Null Represents no RestLogger.

Method Summary

Modifier and Type	Method and Description
void	log(Level level, String msg, Object... args) Log a message.
void	log(Level level, Throwable cause, String msg, Object... args) Log a message to the logger.
void	logObjects(Level level, String msg, Object... args) Same as log(Level, String, Object...) excepts runs the arguments through JsonSerializer.DEFAULT_LAX_READABLE.
void	onError(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res, RestException e) Callback method for logging errors during HTTP requests.

Method Detail

log

void log(Level level,
         Throwable cause,
         String msg,
         Object... args)

Log a message to the logger.

Parameters:

level - The log level.

cause - The cause.

msg - The message to log.

args - Optional MessageFormat-style arguments.

log

void log(Level level,
         String msg,
         Object... args)

Log a message.

Parameters:

level - The log level.

msg - The message to log.

args - Optional MessageFormat-style arguments.

logObjects

void logObjects(Level level,
                String msg,
                Object... args)

Same as log(Level, String, Object...) excepts runs the arguments through JsonSerializer.DEFAULT_LAX_READABLE.

Serialization of arguments do not occur if message is not logged, so it's safe to use this method from within debug log statements.

Example:

logObjects(DEBUG, "Pojo contents:\n{0}", myPojo);

Parameters:

level - The log level.

msg - The message to log.

args - Optional MessageFormat-style arguments.

onError

void onError(javax.servlet.http.HttpServletRequest req,
             javax.servlet.http.HttpServletResponse res,
             RestException e)

Callback method for logging errors during HTTP requests.

Typically, subclasses will override this method and log errors themselves.

The default implementation simply logs errors to the RestServlet logger.

Here's a typical implementation showing how stack trace hashing can be used to reduce log file sizes...

protected void onError(HttpServletRequest req, HttpServletResponse res, RestException e, boolean noTrace) { String qs = req.getQueryString(); String msg = "HTTP " + req.getMethod() + " " + e.getStatus() + " " + req.getRequestURI() + (qs == null ? "" : "?" + qs); int c = e.getOccurrence(); // REST_useStackTraceHashes is disabled, so we have to log the exception every time. if (c == 0) myLogger.log(Level.WARNING, format("[%s] %s", e.getStatus(), msg), e); // This is the first time we've countered this error, so log a stack trace // unless ?noTrace was passed in as a URL parameter. else if (c == 1 && ! noTrace) myLogger.log(Level.WARNING, format("[%h.%s.%s] %s", e.hashCode(), e.getStatus(), c, msg), e); // This error occurred before. // Only log the message, not the stack trace. else myLogger.log(Level.WARNING, format("[%h.%s.%s] %s, %s", e.hashCode(), e.getStatus(), c, msg, e.getLocalizedMessage())); }

Parameters:

req - The servlet request object.

res - The servlet response object.

e - Exception indicating what error occurred.