com.wutka.util
Class Log

java.lang.Object
  |
  +--com.wutka.util.Log

public class Log

extends java.lang.Object

A general mechanism for logging error messages. The Log class supports different clients so messages can be logged in different ways. A log entry has a severity associated with it. Log clients register to receive log messages with a minimum severity value. If there are no clients logging at the entry's severity, no further processing takes place. Thus, the overhead for debug messages is not very heavy.

Field Summary

static java.lang.String	ALL For log clients, grab messages for all subsystems
protected static java.util.Hashtable	clients The clients currently registered with the logger
static java.lang.String	DEFAULT For a log entry, a default location for log messages not associated with a particular subsystem.
protected static java.lang.String	hexDigits
protected static java.util.Hashtable	minLevels The minimum levels being logged for each subsystem

Constructor Summary

Log()

Method Summary

static void	addClient(java.lang.String subsystem, LogSeverity minSeverity, LogClient theClient) Add a new client for a particular subsystem and severity level
static void	logBytes(LogSeverity severity, java.lang.String message, byte[] data) Logs a text message and a hex dump of data to the default subsystem
static void	logBytes(LogSeverity severity, java.lang.String message, byte[] data, int offset, int length) Logs a text message and a hex dump of data to the default subsystem
static void	logBytes(LogSeverity severity, java.lang.String subsystem, java.lang.String message, byte[] data) Logs a text message and a hex dump of data for a particular subsystem
static void	logBytes(LogSeverity severity, java.lang.String subsystem, java.lang.String message, byte[] data, int offset, int length) Logs a text message and a hex dump of data for a particular subsystem
static void	logException(LogSeverity severity, java.lang.String message, java.lang.Exception exc) Logs a text message and an exception to the default subsystem
static void	logException(LogSeverity severity, java.lang.String subsystem, java.lang.String message, java.lang.Exception exc) Logs a text message for a particular subsystem
static void	logMessage(LogSeverity severity, java.lang.String message) Logs a text message to the default subsystem
static void	logMessage(LogSeverity severity, java.lang.String subsystem, java.lang.String message) Logs a text message for a particular subsystem
static java.lang.String	makeHexDump(byte[] data, int offset, int length) Creates a string containing a hex dump of the data bytes
protected static void	recomputeMinLevel(java.lang.String subsystem) Recalculate the minimum logging level for a subsystem (and for all)
static void	removeClient(LogClient theClient) Removes a client from all subsystems it is logging
static void	removeClient(java.lang.String subsystem, LogClient theClient) Removes a client that is logging messages for the named subsystems
static boolean	wouldLog(java.lang.String subsystem, LogSeverity severity) Returns true if a message for this subsystem and severity would be logged.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT

public static final java.lang.String DEFAULT

For a log entry, a default location for log messages not associated with a particular subsystem.

ALL

public static final java.lang.String ALL

For log clients, grab messages for all subsystems

clients

protected static java.util.Hashtable clients

The clients currently registered with the logger

minLevels

protected static java.util.Hashtable minLevels

The minimum levels being logged for each subsystem

hexDigits

protected static java.lang.String hexDigits

Constructor Detail

Log

public Log()

Method Detail

addClient

public static void addClient(java.lang.String subsystem,
                             LogSeverity minSeverity,
                             LogClient theClient)

Add a new client for a particular subsystem and severity level

Parameters:

subsystem - The subsystem the client wants to receive messages for (Log.ALL for all subsystems

minSeverity - The minimum threshold for messages to be sent to this client

theClient - The client that will receive the messages

recomputeMinLevel

protected static void recomputeMinLevel(java.lang.String subsystem)

Recalculate the minimum logging level for a subsystem (and for all)

Parameters:

subsystem - The subsystem the level is being computed for

removeClient

public static void removeClient(java.lang.String subsystem,
                                LogClient theClient)

Removes a client that is logging messages for the named subsystems

Parameters:

subsystem - The subsystem the client is being removed from

theClient - The client being removed

removeClient

public static void removeClient(LogClient theClient)

Removes a client from all subsystems it is logging

Parameters:

theClient - being removed

wouldLog

public static boolean wouldLog(java.lang.String subsystem,
                               LogSeverity severity)

Returns true if a message for this subsystem and severity would be logged. This is useful if you want to check before trying to log a message, in case it is too expensive to even try to log the message.

Parameters:

subsystem - The subsystem the message would be logged for

severity - The severity level to test

logMessage

public static void logMessage(LogSeverity severity,
                              java.lang.String message)

Logs a text message to the default subsystem

Parameters:

severity - The severity level of the message

message - The message to be logged

logMessage

public static void logMessage(LogSeverity severity,
                              java.lang.String subsystem,
                              java.lang.String message)

Logs a text message for a particular subsystem

Parameters:

severity - The severity level of the message

subsystem - The subsystem being logged

message - The message to be logged

logException

public static void logException(LogSeverity severity,
                                java.lang.String message,
                                java.lang.Exception exc)

Logs a text message and an exception to the default subsystem

Parameters:

severity - The severity level of the message

message - The message to be logged

exc - The exception to be logged

logException

public static void logException(LogSeverity severity,
                                java.lang.String subsystem,
                                java.lang.String message,
                                java.lang.Exception exc)

Logs a text message for a particular subsystem

Parameters:

severity - The severity level of the message

subsystem - The subsystem being logged

message - The message to be logged

exc - The exception to be logged

logBytes

public static void logBytes(LogSeverity severity,
                            java.lang.String message,
                            byte[] data)

Logs a text message and a hex dump of data to the default subsystem

Parameters:

severity - The severity level of the message

message - The message to be logged

data - The data to be logged

logBytes

public static void logBytes(LogSeverity severity,
                            java.lang.String subsystem,
                            java.lang.String message,
                            byte[] data)

Logs a text message and a hex dump of data for a particular subsystem

Parameters:

severity - The severity level of the message

subsystem - The subsystem being logged

message - The message to be logged

data - The data to be logged

logBytes

public static void logBytes(LogSeverity severity,
                            java.lang.String message,
                            byte[] data,
                            int offset,
                            int length)

Logs a text message and a hex dump of data to the default subsystem

Parameters:

severity - The severity level of the message

message - The message to be logged

data - The data to be logged

offset - The first byte in the data to be logged

length - The number of bytes to be logged

logBytes

public static void logBytes(LogSeverity severity,
                            java.lang.String subsystem,
                            java.lang.String message,
                            byte[] data,
                            int offset,
                            int length)

Logs a text message and a hex dump of data for a particular subsystem

Parameters:

severity - The severity level of the message

subsystem - The subsystem being logged

message - The message to be logged

data - The data to be logged

offset - The first byte in the data to be logged

length - The number of bytes to be logged

makeHexDump

public static java.lang.String makeHexDump(byte[] data,
                                           int offset,
                                           int length)

Creates a string containing a hex dump of the data bytes

Parameters:

data - The bytes to be converted

offset - The offset of the first byte to be converted

length - The number of bytes to be converted

Returns:

A hex dump of the bytes