net.sourceforge.jsxe.util
Class Log

java.lang.Object
  extended bynet.sourceforge.jsxe.util.Log

public class Log
extends Object

This class provides methods for logging events. In terms of functionality, it is somewhere in between System.out.println() and full-blown logging packages such as log4j.

All events are logged to a Swing text document and optionally a stream, and those with a high urgency (warnings and errors) are also printed to standard output.

This class can also optionally redirect standard output and error to the log.

Since:
jsXe 0.4 beta
Version:
$Id: Log.java 994 2006-07-07 03:46:17Z ian_lewis $
Author:
Slava Pestov, Ian Lewis (IanLewis@member.fsf.org)

Field Summary
static int DEBUG
          Debugging message urgency.
static int ERROR
          Error urgency.
static int MAXLINES
          The maximum number of log messages that will be kept in memory.
static int MESSAGE
          Message urgency.
static int NOTICE
          Notice urgency.
static int WARNING
          Warning urgency.
 
Method Summary
static void closeStream()
          Closes the log stream.
static void flushStream()
          Flushes the log stream.
static Document getLogDocument()
          Returns the document where the most recent messages are stored.
static void init(boolean stdio, int level, boolean debug)
          Initializes the log.
static void log(int urgency, Object source, Object message)
          Logs a message.
static void setDebug(boolean debug)
          Sets whether debug is recorded to the log.
static void setLogWriter(Writer stream)
          Writes all currently logged messages to this stream if there was no stream set previously, and sets the stream to write future log messages to.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

MAXLINES

public static final int MAXLINES
The maximum number of log messages that will be kept in memory.

See Also:
Constant Field Values

DEBUG

public static final int DEBUG
Debugging message urgency. Should be used for messages only useful when debugging a problem.

See Also:
Constant Field Values

MESSAGE

public static final int MESSAGE
Message urgency. Should be used for messages which give more detail than notices.

See Also:
Constant Field Values

NOTICE

public static final int NOTICE
Notice urgency. Should be used for messages that directly affect the user.

See Also:
Constant Field Values

WARNING

public static final int WARNING
Warning urgency. Should be used for messages that warrant attention.

See Also:
Constant Field Values

ERROR

public static final int ERROR
Error urgency. Should be used for messages that signal a failure.

See Also:
Constant Field Values
Method Detail

init

public static void init(boolean stdio,
                        int level,
                        boolean debug)
Initializes the log.

Parameters:
stdio - If true, standard output and error will be sent to the log
level - Messages with this log level or higher will be printed to the system console
debug - If true, debug will be printed to the log even if it is not at or higher than the level (second arg)

setLogWriter

public static void setLogWriter(Writer stream)
Writes all currently logged messages to this stream if there was no stream set previously, and sets the stream to write future log messages to.

Parameters:
stream - The writer

getLogDocument

public static Document getLogDocument()
Returns the document where the most recent messages are stored. The document of a Swing text area can be set to this to graphically view log messages.


flushStream

public static void flushStream()
Flushes the log stream.


closeStream

public static void closeStream()
Closes the log stream. Should be done before your program exits.


log

public static void log(int urgency,
                       Object source,
                       Object message)
Logs a message. This method is thread-safe.

The following code sends a typical debugging message to the activity log:

Log.log(Log.DEBUG,this,"counter = " + counter);
The corresponding activity log entry might read as follows:
[debug] JavaParser: counter = 15

Parameters:
urgency - The urgency; can be one of DEBUG, MESSAGE, NOTICE, WARNING, or ERROR.
source - The source of the message, either an object or a class instance. When writing log messages from macros, set this parameter to BeanShell.class to make macro errors easier to spot in the activity log.
message - The message. This can either be a string or an exception

setDebug

public static void setDebug(boolean debug)
Sets whether debug is recorded to the log.

Parameters:
debug - If true, debug will be printed to the log even if it is not at or higher than the level.