Class JulLogger

java.lang.Object

com.databricks.jdbc.log.JulLogger

All Implemented Interfaces:

JdbcLogger

public class JulLogger
extends Object
implements JdbcLogger

The JulLogger class provides an implementation of the JdbcLogger interface using the Java Util Logging (JUL) framework. It supports logging messages at different levels such as trace, debug, info, warn, and error, both with and without associated Throwable objects.

This class also includes a static method to initialize the logger with custom configurations such as log level, log directory, log file size, and log file count. It supports logging to both the console and file system based on the provided configuration.

Log messages include the name of the class and method from where the logging request was made, providing a clear context for the log messages. This is achieved by analyzing the stack trace to find the caller information.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DATABRICKS_LOG_FILE
static final String	DRIVER_CLASS_PREFIX
protected static boolean	isLoggerInitialized
static final String	JAVA_UTIL_LOGGING_CONFIG_FILE
protected Logger	logger
static final String	PARENT_CLASS_PREFIX
static final String	STDOUT

Constructor Summary

Constructors

Constructor	Description
JulLogger(String name)	Constructs a new JulLogger object with the specified name.

Method Summary

Modifier and Type	Method	Description
void	debug(String message)
void	debug(String format, Object... arguments)
void	error(String message)
void	error(String format, Object... arguments)
void	error(Throwable throwable, String message)
void	error(Throwable throwable, String format, Object... arguments)
protected static String[]	getCaller()	Retrieves the class name and method name of the caller that initiated the logging request.
protected static String	getLogPattern(String logDir)	Generates the log file pattern based on the provided log directory.
void	info(String message)
void	info(String format, Object... arguments)
static void	initLogger(Level level, String logDir, int logFileSizeBytes, int logFileCount)	Initializes the logger with the specified configuration.
void	trace(String message)
void	trace(String format, Object... arguments)
void	warn(String message)
void	warn(String format, Object... arguments)

Methods inherited from class java.lang.Object

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

Field Details

STDOUT

public static final String STDOUT

See Also:

• Constant Field Values

PARENT_CLASS_PREFIX

public static final String PARENT_CLASS_PREFIX

DRIVER_CLASS_PREFIX

public static final String DRIVER_CLASS_PREFIX

DATABRICKS_LOG_FILE

public static final String DATABRICKS_LOG_FILE

See Also:

• Constant Field Values

JAVA_UTIL_LOGGING_CONFIG_FILE

public static final String JAVA_UTIL_LOGGING_CONFIG_FILE

See Also:

• Constant Field Values

logger

protected Logger logger

isLoggerInitialized

protected static volatile boolean isLoggerInitialized

Constructor Details

JulLogger

public JulLogger(String name)

Constructs a new JulLogger object with the specified name.

Method Details

trace

public void trace(String message)

Specified by:

trace in interface JdbcLogger

trace

public void trace(String format,
 Object... arguments)

Specified by:

trace in interface JdbcLogger

debug

public void debug(String message)

Specified by:

debug in interface JdbcLogger

debug

public void debug(String format,
 Object... arguments)

Specified by:

debug in interface JdbcLogger

info

public void info(String message)

Specified by:

info in interface JdbcLogger

info

public void info(String format,
 Object... arguments)

Specified by:

info in interface JdbcLogger

warn

public void warn(String message)

Specified by:

warn in interface JdbcLogger

warn

public void warn(String format,
 Object... arguments)

Specified by:

warn in interface JdbcLogger

error

public void error(String message)

Specified by:

error in interface JdbcLogger

error

public void error(String format,
 Object... arguments)

Specified by:

error in interface JdbcLogger

error

public void error(Throwable throwable,
 String message)

Specified by:

error in interface JdbcLogger

error

public void error(Throwable throwable,
 String format,
 Object... arguments)

Specified by:

error in interface JdbcLogger

initLogger

public static void initLogger(Level level,
 String logDir,
 int logFileSizeBytes,
 int logFileCount)
                       throws IOException

Initializes the logger with the specified configuration. This method is synchronized to prevent concurrent modifications to the logger configuration.

Parameters:

level - the log level

logDir - the directory for log files or STDOUT for console output

logFileSizeBytes - the maximum size of a single log file in bytes

logFileCount - the number of log files to rotate

Throws:

IOException - if an I/O error occurs

getCaller

protected static String[] getCaller()

Retrieves the class name and method name of the caller that initiated the logging request. This method navigates the stack trace to find the first method outside the known logging methods, providing the context from where the log was called. This is particularly useful for including in log messages to identify the source of the log entry.

The method uses a two-step filtering process on the stack trace:

1. It first drops stack trace elements until it finds one whose method name is a known logging method (e.g., trace, debug, info, warn, error).
2. Then, it continues to drop elements until it finds the first method not in the set of logging methods, which is considered the caller.

getLogPattern

protected static String getLogPattern(String logDir)

Generates the log file pattern based on the provided log directory. If the log directory is specified as "STDOUT", logging will be directed to the console. Otherwise, it ensures the directory exists and resolves the log file path within it.