org.apache.juneau.rest

Class BasicRestLogger

java.lang.Object

org.apache.juneau.rest.BasicRestLogger

All Implemented Interfaces:

RestLogger

Direct Known Subclasses:

NoOpRestLogger

public class BasicRestLogger
extends Object
implements RestLogger

Logging utility class.

Subclasses can override these methods to tailor logging of HTTP requests.
Subclasses MUST implement a no-arg public constructor.

See Also:

• Overview > juneau-rest-server > Logging and Error Handling

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.juneau.rest.RestLogger

RestLogger.Null

Constructor Summary

Constructors

Constructor and Description
BasicRestLogger()

Method Summary

Modifier and Type	Method and Description
protected Logger	getLogger() Returns the Java logger used for logging.
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.
protected boolean	shouldLog(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res, RestException e) Returns true if the specified exception should be logged.
protected boolean	shouldLogStackTrace(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res, RestException e) Returns true if a stack trace should be logged for this exception.

Methods inherited from class java.lang.Object

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

Constructor Detail

BasicRestLogger

public BasicRestLogger()

Method Detail

getLogger

protected Logger getLogger()

Returns the Java logger used for logging.

Subclasses can provide their own logger. The default implementation returns the logger created using Logger.getLogger(getClass()).

Returns:

The logger used for logging.

log

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

Log a message to the logger.

Subclasses can override this method if they wish to log messages using a library other than Java Logging (e.g. Apache Commons Logging).

Specified by:

log in interface RestLogger

Parameters:

level - The log level.

cause - The cause.

msg - The message to log.

args - Optional MessageFormat-style arguments.

log

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

Log a message.

Equivalent to calling log(level, null, msg, args);

Specified by:

log in interface RestLogger

Parameters:

level - The log level.

msg - The message to log.

args - Optional MessageFormat-style arguments.

logObjects

public 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);

Specified by:

logObjects in interface RestLogger

Parameters:

level - The log level.

msg - The message to log.

args - Optional MessageFormat-style arguments.

onError

public 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())); }

Specified by:

onError in interface RestLogger

Parameters:

req - The servlet request object.

res - The servlet response object.

e - Exception indicating what error occurred.

shouldLog

protected boolean shouldLog(javax.servlet.http.HttpServletRequest req,
                            javax.servlet.http.HttpServletResponse res,
                            RestException e)

Returns true if the specified exception should be logged.

Subclasses can override this method to provide their own logic for determining when exceptions are logged.

The default implementation will return false if "noTrace=true" is passed in the query string or No-Trace: true is specified in the header.

Parameters:

req - The HTTP request.

res - The HTTP response.

e - The exception.

Returns:

true if exception should be logged.

shouldLogStackTrace

protected boolean shouldLogStackTrace(javax.servlet.http.HttpServletRequest req,
                                      javax.servlet.http.HttpServletResponse res,
                                      RestException e)

Returns true if a stack trace should be logged for this exception.

Subclasses can override this method to provide their own logic for determining when stack traces are logged.

The default implementation will only log a stack trace if RestException.getOccurrence() returns 1 and the exception is not one of the following:

• HttpServletResponse.SC_UNAUTHORIZED
• HttpServletResponse.SC_FORBIDDEN
• HttpServletResponse.SC_NOT_FOUND

Parameters:

req - The HTTP request.

res - The HTTP response.

e - The exception.

Returns:

true if stack trace should be logged.