package se.rhel.util;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Date;
/**
* A low overhead, lightweight logging system.
* @author Nathan Sweet <misc@n4te.com>
*/
public class Log {
/** No logging at all. */
static public final int LEVEL_NONE = 6;
/** Critical errors. The application may no longer work correctly. */
static public final int LEVEL_ERROR = 5;
/** Important warnings. The application will continue to work correctly. */
static public final int LEVEL_WARN = 4;
/** Informative messages. Typically used for deployment. */
static public final int LEVEL_INFO = 3;
/** Debug messages. This level is useful during development. */
static public final int LEVEL_DEBUG = 2;
/** Trace messages. A lot of information is logged, so this level is usually only needed when debugging a problem. */
static public final int LEVEL_TRACE = 1;
/**
* The level of messages that will be logged. Compiling this and the booleans below as "final" will cause the compiler to
* remove all "if (Log.info) ..." type statements below the set level.
*/
static private int level = LEVEL_INFO;
/** True when the ERROR level will be logged. */
static public boolean ERROR = level <= LEVEL_ERROR;
/** True when the WARN level will be logged. */
static public boolean WARN = level <= LEVEL_WARN;
/** True when the INFO level will be logged. */
static public boolean INFO = level <= LEVEL_INFO;
/** True when the DEBUG level will be logged. */
static public boolean DEBUG = level <= LEVEL_DEBUG;
/** True when the TRACE level will be logged. */
static public boolean TRACE = level <= LEVEL_TRACE;
/**
* Sets the level to log. If a version of this class is being used that has a final log level, this has no affect.
*/
static public void set (int level) {
// Comment out method contents when compiling fixed level JARs.
Log.level = level;
ERROR = level <= LEVEL_ERROR;
WARN = level <= LEVEL_WARN;
INFO = level <= LEVEL_INFO;
DEBUG = level <= LEVEL_DEBUG;
TRACE = level <= LEVEL_TRACE;
}
static public void NONE () {
set(LEVEL_NONE);
}
static public void ERROR () {
set(LEVEL_ERROR);
}
static public void WARN () {
set(LEVEL_WARN);
}
static public void INFO () {
set(LEVEL_INFO);
}
static public void DEBUG () {
set(LEVEL_DEBUG);
}
static public void TRACE () {
set(LEVEL_TRACE);
}
/**
* Sets the logger that will write the log messages.
*/
static public void setLogger (Logger logger) {
Log.logger = logger;
}
static private Logger logger = new Logger();
static public void error (String message, Throwable ex) {
if (ERROR) logger.log(LEVEL_ERROR, null, message, ex);
}
static public void error (String category, String message, Throwable ex) {
if (ERROR) logger.log(LEVEL_ERROR, category, message, ex);
}
static public void error (String message) {
if (ERROR) logger.log(LEVEL_ERROR, null, message, null);
}
static public void error (String category, String message) {
if (ERROR) logger.log(LEVEL_ERROR, category, message, null);
}
static public void warn (String message, Throwable ex) {
if (WARN) logger.log(LEVEL_WARN, null, message, ex);
}
static public void warn (String category, String message, Throwable ex) {
if (WARN) logger.log(LEVEL_WARN, category, message, ex);
}
static public void warn (String message) {
if (WARN) logger.log(LEVEL_WARN, null, message, null);
}
static public void warn (String category, String message) {
if (WARN) logger.log(LEVEL_WARN, category, message, null);
}
static public void info (String message, Throwable ex) {
if (INFO) logger.log(LEVEL_INFO, null, message, ex);
}
static public void info (String category, String message, Throwable ex) {
if (INFO) logger.log(LEVEL_INFO, category, message, ex);
}
static public void info (String message) {
if (INFO) logger.log(LEVEL_INFO, null, message, null);
}
static public void info (String category, String message) {
if (INFO) logger.log(LEVEL_INFO, category, message, null);
}
static public void debug (String message, Throwable ex) {
if (DEBUG) logger.log(LEVEL_DEBUG, null, message, ex);
}
static public void debug (String category, String message, Throwable ex) {
if (DEBUG) logger.log(LEVEL_DEBUG, category, message, ex);
}
static public void debug (String message) {
if (DEBUG) logger.log(LEVEL_DEBUG, null, message, null);
}
static public void debug (String category, String message) {
if (DEBUG) logger.log(LEVEL_DEBUG, category, message, null);
}
static public void trace (String message, Throwable ex) {
if (TRACE) logger.log(LEVEL_TRACE, null, message, ex);
}
static public void trace (String category, String message, Throwable ex) {
if (TRACE) logger.log(LEVEL_TRACE, category, message, ex);
}
static public void trace (String message) {
if (TRACE) logger.log(LEVEL_TRACE, null, message, null);
}
static public void trace (String category, String message) {
if (TRACE) logger.log(LEVEL_TRACE, category, message, null);
}
private Log () {
}
/**
* Performs the actual logging. Default implementation logs to System.out. Extended and use {@link Log#logger} set to handle
* logging differently.
*/
static public class Logger {
private long firstLogTime = new Date().getTime();
public void log (int level, String category, String message, Throwable ex) {
StringBuilder builder = new StringBuilder(256);
long time = new Date().getTime() - firstLogTime;
long minutes = time / (1000 * 60);
long seconds = time / (1000) % 60;
if (minutes <= 9) builder.append('0');
builder.append(minutes);
builder.append(':');
if (seconds <= 9) builder.append('0');
builder.append(seconds);
switch (level) {
case LEVEL_ERROR:
builder.append(" ERROR: ");
break;
case LEVEL_WARN:
builder.append(" WARN: ");
break;
case LEVEL_INFO:
builder.append(" INFO: ");
break;
case LEVEL_DEBUG:
builder.append(" DEBUG: ");
break;
case LEVEL_TRACE:
builder.append(" TRACE: ");
break;
}
if (category != null) {
builder.append('[');
builder.append(category);
builder.append("] ");
}
builder.append(message);
if (ex != null) {
StringWriter writer = new StringWriter(256);
ex.printStackTrace(new PrintWriter(writer));
builder.append('\n');
builder.append(writer.toString().trim());
}
print(builder.toString());
}
/**
* Prints the message to System.out. Called by the default implementation of {@link #log(int, String, String, Throwable)}.
*/
protected void print (String message) {
System.out.println(message);
}
}
}