Java tutorial
/* * WANDORA * Knowledge Extraction, Management, and Publishing Application * http://wandora.org * * Copyright (C) 2004-2016 Wandora Team * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * */ package org.wandora.modules; import java.util.HashMap; import java.util.logging.Level; import org.apache.commons.logging.Log; import org.apache.commons.logging.impl.Jdk14Logger; import org.apache.commons.logging.impl.SimpleLog; /** * <p> * A module that provides logging facilities for other modules. Logging * modules should follow a slightly different life cycle to other modules. This * is because logging might be needed already in the init or getDependencies * phase of modules while module functions typically become available only after * the module has been started. You should initialise the logging into a state * where it can be fully used already in the init method. * </p> * <p> * This default implementation supports two initialisation parameters. First * parameter is "log", you can use this to specify the logging mechanism that should * be used. This should be an instance of org.apache.commons.logging.Log. If * not specified, the logger of the module manager is used, and if that is not * specified either, a SimpleLog is created which outputs messages to stderr. * </p> * <p> * You may use the logLevel initialisation parameter to set the lowest level of * logging messages that are printed. Messages of lower level than this are * simple ignored. The possible values for this are trace, debug, info, warn, * error, fatal and none. None is used to suppress logging entirely while providing * a logging module for other modules that require it. The default log level * is trace, i.e. all logging messages are printed. However, bear in mind that * the underlying logger may have its own mechanisms to further filter logging * messages. Thus even if this LoggingModule is set to print all messages, the * logging level may be filtered to a higher level elsewhere. This is dependent * on the logging implementation used. * </p> * * @author olli */ public class LoggingModule extends AbstractModule { protected Log log; protected int logLevel = SubLog.LOG_TRACE; public LoggingModule() { } public LoggingModule(Log log) { this.log = log; } public Log getLog() { return log; } public Log getLog(Module module) { String name = module.toString(); return new SubLog(name + " - ", log); } public Log getLog(String moduleName) { return new SubLog(moduleName + " - ", log); } public static Log getLog(String moduleName, Log log) { return new SubLog(moduleName + " - ", log); } public int getLogLevel() { return logLevel; } @Override public void init(ModuleManager manager, HashMap<String, Object> settings) throws ModuleException { Object o = null; o = settings.get("log"); if (o != null && o instanceof Log) log = (Log) o; if (log == null) log = manager.getLogger(); if (log == null) log = new SimpleLog("log"); o = settings.get("logLevel"); if (o != null) { String s = o.toString().trim().toLowerCase(); if (s.equals("all") || s.equals("trace")) logLevel = SubLog.LOG_TRACE; else if (s.equals("debug")) logLevel = SubLog.LOG_DEBUG; else if (s.equals("info")) logLevel = SubLog.LOG_INFO; else if (s.equals("warn") || s.equals("warning")) logLevel = SubLog.LOG_WARN; else if (s.equals("error")) logLevel = SubLog.LOG_ERROR; else if (s.equals("fatal")) logLevel = SubLog.LOG_FATAL; else if (s.equals("none")) logLevel = SubLog.LOG_NONE; if (logLevel > SubLog.LOG_TRACE) log = new SubLog("", log, logLevel); } super.init(manager, settings); } public static class SubLog implements Log { protected Log log; protected String prefix; public static final int LOG_ALL = 0; public static final int LOG_TRACE = 0; public static final int LOG_DEBUG = 1; public static final int LOG_INFO = 2; public static final int LOG_WARN = 3; public static final int LOG_ERROR = 4; public static final int LOG_FATAL = 5; public static final int LOG_NONE = 6; protected int logLevel = LOG_TRACE; public SubLog(String prefix, Log log, int logLevel) { this.logLevel = logLevel; this.prefix = prefix; this.log = log; } public SubLog(String prefix, Log log) { this.prefix = prefix; this.log = log; } public void debug(Object arg0) { if (logLevel <= LOG_DEBUG) log.debug(prefix + arg0); } public void debug(Object arg0, Throwable arg1) { if (logLevel <= LOG_DEBUG) log.debug(prefix + arg0, arg1); } public void error(Object arg0) { if (logLevel <= LOG_ERROR) log.error(prefix + arg0); } public void error(Object arg0, Throwable arg1) { if (logLevel <= LOG_ERROR) log.error(prefix + arg0, arg1); } public void fatal(Object arg0) { if (logLevel <= LOG_FATAL) log.fatal(prefix + arg0); } public void fatal(Object arg0, Throwable arg1) { if (logLevel <= LOG_FATAL) log.fatal(prefix + arg0, arg1); } public void info(Object arg0) { if (logLevel <= LOG_INFO) log.info(prefix + arg0); } public void info(Object arg0, Throwable arg1) { if (logLevel <= LOG_INFO) log.info(prefix + arg0, arg1); } public boolean isDebugEnabled() { return logLevel <= LOG_DEBUG && log.isDebugEnabled(); } public boolean isErrorEnabled() { return logLevel <= LOG_ERROR && log.isErrorEnabled(); } public boolean isFatalEnabled() { return logLevel <= LOG_FATAL && log.isFatalEnabled(); } public boolean isInfoEnabled() { return logLevel <= LOG_INFO && log.isInfoEnabled(); } public boolean isTraceEnabled() { return logLevel <= LOG_TRACE && log.isTraceEnabled(); } public boolean isWarnEnabled() { return logLevel <= LOG_WARN && log.isWarnEnabled(); } public void trace(Object arg0) { if (logLevel <= LOG_TRACE) log.trace(prefix + arg0); } public void trace(Object arg0, Throwable arg1) { if (logLevel <= LOG_TRACE) log.trace(prefix + arg0, arg1); } public void warn(Object arg0) { if (logLevel <= LOG_WARN) log.warn(prefix + arg0); } public void warn(Object arg0, Throwable arg1) { if (logLevel <= LOG_WARN) log.warn(prefix + arg0, arg1); } } }