org.jlf.log
Class Log

java.lang.Object
  |
  +--org.jlf.log.Log

Direct Known Subclasses:

MultiThreadLog

public class Log

extends java.lang.Object

Log is the base class which defines all of the logging constants and implements any general logging responsibilities. It dispatches the actual logging information over to a concrete subclass of AbstractLoggingMechanism to do the work of writing out the log information.

This class could be extended to do application-specific behavior, or better yet you could create a class "wrapper" like AppLog to make instances well-known Singletons with handy static/class methods.

See Also:

AbstractLoggingMechanism, AppLog

Field Summary

static int	CRITICAL_ERROR_LEVEL The system encountered a critical error at this logging level, which affects the accuracy, integrity, reliability, or capability of the system.
protected int	currentLoggingLevel Keep the logging level the log is currently operating at.
protected java.util.Date	dateOpened Keeps the date the log opened
static int	DEACTIVATE_LEVEL Turns the log off, no messages are logged
static int	DETAIL_LEVEL Moderately detailed logging level to be used to help debug typical problems in the system.
static int	ERROR_LEVEL The system encountered an unexpected error at this logging level, which probably means the code intercepted an error it cannot handle.
static int	INFO_LEVEL Normal logging level.
protected java.lang.String	logFieldSeparator Keeps a string demarking fields within the log file.
static java.lang.String[]	LOGGING_MECHANISMS List of all available logging mechanisms.
protected java.util.Vector	loggingMechanisms Keeps a collection of logging mechanisms to use when writing out the log.
protected java.lang.String	name Keeps the name of the Log instance.
static java.lang.String	SHARED_DATED_FILE_MECHANISM Logging mechanism to log all messages to a shared file for any Log instances using this mechanism.
static java.lang.String	SHARED_FILE_MECHANISM Logging mechanism to log all messages to a shared file for any Log instances using this mechanism.
static java.lang.String	SMTP_MECHANISM Logging mechanism to log certain priority messages to an email mailbox via SMTP.
static java.lang.String	STANDARD_ERR_MECHANISM Logging mechanism to log all messages to System.err
static int	TRACE_LEVEL Most detailed logging level.
static java.lang.String	UNIQUE_DATED_FILE_MECHANISM Logging mechanism to log all messages to a unique file specific to that Log instance.
static java.lang.String	UNIQUE_FILE_MECHANISM Logging mechanism to log all messages to a unique file specific to that Log instance.
static int	WARNING_LEVEL The system encountered an expected error situation.

Constructor Summary

protected	Log() Class constructor to properly create and register a new log.
	Log(java.lang.String name) Public constructor to register a new log with a particular name.

Method Summary

AbstractLoggingMechanism	addLoggingMechanism(java.lang.String loggingMechanismName) Adds a Logging Mechanism to the list of mechanisms that this log writes to.
protected void	finalize() Must close the log for the application if the application did not or could not.
java.util.Date	getDateOpened() Return the date the log was opened, only valid if the log is currently open.
java.lang.String	getLogFieldSeparator() Gets the string that delimits the various fields of a log entry
int	getLoggingLevel() Gets the logging level of the current log.
AbstractLoggingMechanism	getLoggingMechanism(java.lang.String loggingMechanismName) If a logging mechanism of the type input is in effect for this log, return the logging mechanism instance matching the name given as input.
java.util.Vector	getLoggingMechanisms() Returns a Vector of logging mechanisms currently active for the log.
java.lang.String	getName() Return the name of the log, usually passed in by the constructor.
boolean	isLoggingEnabledFor(int loggingLevel) Returns true if the current logging level of the log is set to enable logging a string at the input logging level.
boolean	isOpen() Return whether the log is open (is not deactivated).
void	logString(java.lang.String logString, int loggingLevel) Adds a message string to the log if the log's level is currently set at or above the loggingLevel passed in.
void	removeAllLoggingMechanisms() Removes all Logging Mechanisms from the list of mechanisms that this log writes to.
void	removeLoggingMechanism(java.lang.String loggingMechanismName) Removes an active Logging Mechanism from the list of mechanisms that this log writes to.
void	setLogFieldSeparator(java.lang.String logFieldSeparator) Sets the string that delimits the various fields of a log entry
void	setLoggingLevel(int newLoggingLevel) Changes the logging level of the current log.

Methods inherited from class java.lang.Object

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

Field Detail

DEACTIVATE_LEVEL

public static final int DEACTIVATE_LEVEL

Turns the log off, no messages are logged

See Also:

Constant Field Values

CRITICAL_ERROR_LEVEL

public static final int CRITICAL_ERROR_LEVEL

The system encountered a critical error at this logging level, which affects the accuracy, integrity, reliability, or capability of the system. Someone should be paged to address the error as soon as possible.

See Also:

Constant Field Values

ERROR_LEVEL

public static final int ERROR_LEVEL

The system encountered an unexpected error at this logging level, which probably means the code intercepted an error it cannot handle. This error is not of a critical nature and can be recovered from automatically. Someone should probably be emailed to resolve the error in the near future to increase the reliability of the product.

See Also:

Constant Field Values

WARNING_LEVEL

public static final int WARNING_LEVEL

The system encountered an expected error situation. The system recovered from it but the fact that it happened should be recorded to see how frequent it happens.

See Also:

Constant Field Values

INFO_LEVEL

public static final int INFO_LEVEL

Normal logging level. All interesting periodic events should be logged at this level so someone looking through the log can see the amount and kind of processing happening in the system.

See Also:

Constant Field Values

DETAIL_LEVEL

public static final int DETAIL_LEVEL

Moderately detailed logging level to be used to help debug typical problems in the system. Not so detailed that the big picture gets lost.

See Also:

Constant Field Values

TRACE_LEVEL

public static final int TRACE_LEVEL

Most detailed logging level. Everything sent to the log will be logged. Use this level to trace system execution for really nasty problems.

See Also:

Constant Field Values

STANDARD_ERR_MECHANISM

public static final java.lang.String STANDARD_ERR_MECHANISM

Logging mechanism to log all messages to System.err

See Also:

Constant Field Values

UNIQUE_FILE_MECHANISM

public static final java.lang.String UNIQUE_FILE_MECHANISM

Logging mechanism to log all messages to a unique file specific to that Log instance. Reuse the same log file name (append to it) if it already exists.

See Also:

Constant Field Values

UNIQUE_DATED_FILE_MECHANISM

public static final java.lang.String UNIQUE_DATED_FILE_MECHANISM

Logging mechanism to log all messages to a unique file specific to that Log instance. Don't append to an existing log, instead create a new one with a date stamp.

See Also:

Constant Field Values

SHARED_FILE_MECHANISM

public static final java.lang.String SHARED_FILE_MECHANISM

Logging mechanism to log all messages to a shared file for any Log instances using this mechanism. Append to an existing log, if it already exists.

See Also:

Constant Field Values

SHARED_DATED_FILE_MECHANISM

public static final java.lang.String SHARED_DATED_FILE_MECHANISM

Logging mechanism to log all messages to a shared file for any Log instances using this mechanism. Don't append to an existing log, instead create a new one with a date stamp.

See Also:

Constant Field Values

SMTP_MECHANISM

public static final java.lang.String SMTP_MECHANISM

Logging mechanism to log certain priority messages to an email mailbox via SMTP.

See Also:

Constant Field Values

LOGGING_MECHANISMS

public static final java.lang.String[] LOGGING_MECHANISMS

List of all available logging mechanisms.

name

protected java.lang.String name

Keeps the name of the Log instance.

currentLoggingLevel

protected int currentLoggingLevel

Keep the logging level the log is currently operating at.

loggingMechanisms

protected java.util.Vector loggingMechanisms

Keeps a collection of logging mechanisms to use when writing out the log.

dateOpened

protected java.util.Date dateOpened

Keeps the date the log opened

logFieldSeparator

protected java.lang.String logFieldSeparator

Keeps a string demarking fields within the log file.

Constructor Detail

Log

protected Log()

Class constructor to properly create and register a new log. All other constructors and subclasses should eventually call this method!

Log

public Log(java.lang.String name)

Public constructor to register a new log with a particular name. The name of the log is very important. It is used as a key into the log properties file to find settings for how the log is to be opened.

Method Detail

getLoggingLevel

public int getLoggingLevel()

Gets the logging level of the current log.

isLoggingEnabledFor

public boolean isLoggingEnabledFor(int loggingLevel)

Returns true if the current logging level of the log is set to enable logging a string at the input logging level. Use this method in an if statement before you construct a log message for better performance (thanks to suggestion from David Crane).

setLoggingLevel

public void setLoggingLevel(int newLoggingLevel)

Changes the logging level of the current log. Use this method to activate, deactivate, or change the logging detail level of an active log.

getLoggingMechanisms

public java.util.Vector getLoggingMechanisms()

Returns a Vector of logging mechanisms currently active for the log.

Returns:

a Vector of logging mechanisms currently active for the log.

getLoggingMechanism

public AbstractLoggingMechanism getLoggingMechanism(java.lang.String loggingMechanismName)

If a logging mechanism of the type input is in effect for this log, return the logging mechanism instance matching the name given as input.

Parameters:

loggingMechanismName - Name of the logging mechanism to search for, one of the constants in the Log class.

Returns:

The concrete instance of an AbstractLoggingMechanism that is currently in effect for the Log if one found, null if not.

addLoggingMechanism

public AbstractLoggingMechanism addLoggingMechanism(java.lang.String loggingMechanismName)

Adds a Logging Mechanism to the list of mechanisms that this log writes to. Opens the mechanism and registers it also.

Parameters:

loggingMechanismName - The name of the Logging Mechanism.

Returns:

The concrete instance of AbstractLoggingMechanism that implements the mechanism just added, null if an error occurred like the log could not be opened or that log was previously opened!

removeLoggingMechanism

public void removeLoggingMechanism(java.lang.String loggingMechanismName)

Removes an active Logging Mechanism from the list of mechanisms that this log writes to. Closes the mechanism and deregisters it also.

Parameters:

loggingMechanismName - The name of the Logging Mechanism to remove.

removeAllLoggingMechanisms

public void removeAllLoggingMechanisms()

Removes all Logging Mechanisms from the list of mechanisms that this log writes to. Closes the mechanisms and deregisters them also.

logString

public void logString(java.lang.String logString,
                      int loggingLevel)

Adds a message string to the log if the log's level is currently set at or above the loggingLevel passed in.

Parameters:

logString - The string to write to all logging mechanisms

loggingLevel - The level at which to log the string.

finalize

protected void finalize()
                 throws java.lang.Throwable

Must close the log for the application if the application did not or could not.

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable - Default finalizer exception

getLogFieldSeparator

public java.lang.String getLogFieldSeparator()

Gets the string that delimits the various fields of a log entry

setLogFieldSeparator

public void setLogFieldSeparator(java.lang.String logFieldSeparator)

Sets the string that delimits the various fields of a log entry

getName

public java.lang.String getName()

Return the name of the log, usually passed in by the constructor.

isOpen

public boolean isOpen()

Return whether the log is open (is not deactivated).

getDateOpened

public java.util.Date getDateOpened()

Return the date the log was opened, only valid if the log is currently open.