org.ceryle.util.log
Class Logger

java.lang.Object
  org.ceryle.util.log.Logger

public class Logger
extends Object

A singleton class that writes to a log file. This is designed as a simple logger, with none of the complexity of say, the new Java Logging API.

The two properties this class responds to are:

message.verbose

When true, messaging is set to verbose mode.

http://purl.org/ceryle/log/properties/log-active

When true, indicates logging should be active.

http://purl.org/ceryle/log/properties/log.append

When true, log messages are appended to the existing log rather than overwriting a new one.

Log Filename

The constructor's filename parameter is optional. If it is not provided, a check for a System property "ceryle.log.filename" will be made. Absent a provided value, the default LOG_FILENAME ("application.log") will be used.

This class will be deprecated and replaced with Log4J.

Since:

JDK1.3

Version:

$Id: Logger.java,v 3.10 2007-06-15 12:10:02 altheim Exp $

Author:

Murray Altheim

Field Summary

static boolean	autoflush When true, flushes after each write.
static String	LOG_ACTIVE Feature identifier: log active.
static String	LOG_APPEND Feature identifier: log append.
String	LOG_CLOSE_CODE Single character state code indicating a close log message.
String	LOG_ERROR_CODE Single character state code indicating an error message.
String	LOG_FATAL_CODE Single character state code indicating a fatal message.
static String	LOG_FEATURE_PFX Logger Feature prefix.
static String	LOG_FILENAME The default filename for the log file.
String	LOG_OK_CODE Single character state code indicating a normal log message.
String	LOG_OPEN_CODE Single character state code indicating an open log message.
static String	LOG_PROPERTY_FILENAME Log filename property identifier.
String	LOG_UNKNOWN_CODE Single character state code indicating an unknown state, or simply a log message.
String	LOG_WARNING_CODE Single character state code indicating a warning message.
static double	logMaxSize The size limit of the log file (in MB).
static char	RDELIM The record delimiter character used (at beginning of line).

Method Summary

void	close() Closes the log file if open.
void	flush() Flush the writer.
static Properties	getDefaultProperties() Return the default properties for the Logger.
static Logger	getInstance(MessageHandler messagehandler, String filename, Properties properties) As this is a singleton class, this returns the single instance of this class.
double	getLogFileLength() Returns the length of the log file (in MB).
String	getLogFileName() Returns the name of the log file (in MB).
Writer	getWriter() Returns the writer.
void	open() Opens log file for writing, defining the internal Writer.
String	write(String message) Write the String message to the current log file if active, returning the message value.
String	write(String timestamp, String message) Write the String message to the current log file if active, returning the message value.
String	write(String state, String timestamp, String message) Write the String message to the current log file if active, returning the message value.

Methods inherited from class java.lang.Object

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

Field Detail

LOG_PROPERTY_FILENAME

public static final String LOG_PROPERTY_FILENAME

Log filename property identifier.

See Also:

Constant Field Values

LOG_FEATURE_PFX

public static final String LOG_FEATURE_PFX

Logger Feature prefix.

See Also:

Constant Field Values

LOG_ACTIVE

public static final String LOG_ACTIVE

Feature identifier: log active.

See Also:

Constant Field Values

LOG_APPEND

public static final String LOG_APPEND

Feature identifier: log append.

See Also:

Constant Field Values

LOG_FILENAME

public static final String LOG_FILENAME

The default filename for the log file. The value is "application.log".

See Also:

Constant Field Values

logMaxSize

public static double logMaxSize

The size limit of the log file (in MB). Services provides a warning and option to delete the log, should the size increase above this limit. Default is 5 (5MB).

autoflush

public static boolean autoflush

When true, flushes after each write.

LOG_UNKNOWN_CODE

public final String LOG_UNKNOWN_CODE

Single character state code indicating an unknown state, or simply a log message. Value is "L".

See Also:

Constant Field Values

LOG_OPEN_CODE

public final String LOG_OPEN_CODE

Single character state code indicating an open log message. Value is "O".

See Also:

Constant Field Values

LOG_CLOSE_CODE

public final String LOG_CLOSE_CODE

Single character state code indicating a close log message. Value is "C".

See Also:

Constant Field Values

LOG_OK_CODE

public final String LOG_OK_CODE

Single character state code indicating a normal log message. Value is "M".

See Also:

Constant Field Values

LOG_WARNING_CODE

public final String LOG_WARNING_CODE

Single character state code indicating a warning message. Value is "W".

See Also:

Constant Field Values

LOG_ERROR_CODE

public final String LOG_ERROR_CODE

Single character state code indicating an error message. Value is "E".

See Also:

Constant Field Values

LOG_FATAL_CODE

public final String LOG_FATAL_CODE

Single character state code indicating a fatal message. Value is "F".

See Also:

Constant Field Values

RDELIM

public static final char RDELIM

The record delimiter character used (at beginning of line).

See Also:

Constant Field Values

Method Detail

getDefaultProperties

public static Properties getDefaultProperties()

Return the default properties for the Logger. This flags the log append property as true.

getInstance

public static Logger getInstance(MessageHandler messagehandler,
                                 String filename,
                                 Properties properties)
                          throws IOException

As this is a singleton class, this returns the single instance of this class. If filename is null, the default will be used.

Throws:

IOException

write

public String write(String message)

Write the String message to the current log file if active, returning the message value.

write

public String write(String timestamp,
                    String message)

Write the String message to the current log file if active, returning the message value. The String for timestamp is optional, as it will be generated if null.

write

public String write(String state,
                    String timestamp,
                    String message)

Write the String message to the current log file if active, returning the message value. The Strings for state and timestamp are optional. If timestamp is null it will be generated.

open

public void open()
          throws IOException

Opens log file for writing, defining the internal Writer. The internal Writer is opened upon class instantiation, so unless the Writer is closed via close(), this method has no effect.

Throws:

IOException

getLogFileName

public String getLogFileName()

Returns the name of the log file (in MB). If unable to obtain the File, a null is returned.

getLogFileLength

public double getLogFileLength()

Returns the length of the log file (in MB). If unable to obtain the File, a zero is returned.

getWriter

public Writer getWriter()

Returns the writer. This is used only for synchronization.

flush

public void flush()
           throws IOException

Flush the writer.

Throws:

IOException

close

public void close()
           throws IOException

Closes the log file if open.

Throws:

IOException