001/**
002 *   GRANITE DATA SERVICES
003 *   Copyright (C) 2006-2013 GRANITE DATA SERVICES S.A.S.
004 *
005 *   This file is part of the Granite Data Services Platform.
006 *
007 *   Granite Data Services is free software; you can redistribute it and/or
008 *   modify it under the terms of the GNU Lesser General Public
009 *   License as published by the Free Software Foundation; either
010 *   version 2.1 of the License, or (at your option) any later version.
011 *
012 *   Granite Data Services is distributed in the hope that it will be useful,
013 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
014 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
015 *   General Public License for more details.
016 *
017 *   You should have received a copy of the GNU Lesser General Public
018 *   License along with this library; if not, write to the Free Software
019 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
020 *   USA, or see <http://www.gnu.org/licenses/>.
021 */
022package org.granite.logging;
023
024import java.lang.reflect.Constructor;
025
026import org.granite.scan.ServiceLoader;
027import org.granite.util.TypeUtil;
028
029/**
030 * @author Franck WOLFF
031 */
032public abstract class Logger {
033
034    ///////////////////////////////////////////////////////////////////////////
035    // Fields.
036
037        public static final String LOGGER_IMPL_SYSTEM_PROPERTY = "org.granite.logger.impl";
038
039    private static final boolean slf4jAvailable;
040        private static final boolean log4jAvailable;
041        static {
042                boolean slf4j = false;
043        boolean log4j = false;
044                try {
045            TypeUtil.forName("org.slf4j.Logger");
046            slf4j = true;
047        }
048        catch (Exception e) {
049            try {
050                            TypeUtil.forName("org.apache.log4j.Logger");
051                            log4j = true;
052                    }
053            catch (Exception f) {
054            }
055                }
056        slf4jAvailable = slf4j;
057                log4jAvailable = log4j;
058        }
059        
060    private final Object loggerImpl;
061    private final LoggingFormatter formatter;
062
063    ///////////////////////////////////////////////////////////////////////////
064    // Constructor.
065    
066    protected Logger(Object loggerImpl, LoggingFormatter formatter) {
067        this.loggerImpl = loggerImpl;
068        this.formatter = formatter;
069    }
070
071    ///////////////////////////////////////////////////////////////////////////
072    // Getters.
073    
074    protected Object getLoggerImpl() {
075        return loggerImpl;
076    }
077    
078    protected LoggingFormatter getFormatter() {
079                return formatter;
080        }
081
082    ///////////////////////////////////////////////////////////////////////////
083    // Static initializers.
084
085        public static Logger getLogger() {
086        return getLogger(new DefaultLoggingFormatter());
087    }
088
089    public static Logger getLogger(Class<?> clazz) {
090        return getLogger(clazz.getName(), new DefaultLoggingFormatter());
091    }
092
093    public static Logger getLogger(String name) {
094        return getLogger(name, new DefaultLoggingFormatter());
095    }
096
097    public static Logger getLogger(LoggingFormatter formatter) {
098        Throwable t = new Throwable();
099        StackTraceElement[] stes = t.getStackTrace();
100        if (stes.length < 2)
101            throw new RuntimeException("Illegal instantiation context (stacktrace elements should be of length >= 2)", t);
102        return getLogger(stes[1].getClassName());
103    }
104
105    public static Logger getLogger(Class<?> clazz, LoggingFormatter formatter) {
106        return getLogger(clazz.getName(), formatter);
107    }
108
109    public static Logger getLogger(String name, LoggingFormatter formatter) {
110        String loggerImplClass = System.getProperty(LOGGER_IMPL_SYSTEM_PROPERTY);
111        if (loggerImplClass != null) {
112                try {
113                        Class<? extends Logger> clazz = TypeUtil.forName(loggerImplClass, Logger.class);
114                        Constructor<? extends Logger> constructor = clazz.getConstructor(String.class, LoggingFormatter.class);
115                        return constructor.newInstance(name, formatter);
116                        } catch (Exception e) {
117                                throw new RuntimeException(
118                                        "Could not create instance of: " + loggerImplClass +
119                                        " (" + LOGGER_IMPL_SYSTEM_PROPERTY + " system property)", e);
120                        }
121        }
122        
123        ServiceLoader<Logger> loader = ServiceLoader.load(Logger.class);
124        loader.setConstructorParameters(new Class<?>[]{String.class, LoggingFormatter.class}, new Object[]{name, formatter});
125        for (Logger logger : loader)
126                return logger;
127        
128        return slf4jAvailable ? new Slf4jLogger(name, formatter) :
129                (log4jAvailable ? new Log4jLogger(name, formatter) : new JdkLogger(name, formatter));
130    }
131
132    ///////////////////////////////////////////////////////////////////////////
133    // Logging methods.
134
135    public abstract void info(String message, Object... args);
136    public abstract void info(Throwable t, String message, Object... args);
137
138    public abstract void trace(String message, Object... args);
139    public abstract void trace(Throwable t, String message, Object... args);
140    
141    public abstract void warn(String message, Object... args);
142    public abstract void warn(Throwable t, String message, Object... args);
143
144    public abstract void debug(String message, Object... args);
145    public abstract void debug(Throwable t, String message, Object... args);
146
147    public abstract void error(String message, Object... args);
148    public abstract void error(Throwable t, String message, Object... args);
149
150    ///////////////////////////////////////////////////////////////////////////
151    // Configuration.
152
153    public abstract boolean isDebugEnabled();
154
155    public abstract boolean isErrorEnabled();
156
157    public abstract boolean isFatalEnabled();
158
159    public abstract boolean isInfoEnabled();
160
161    public abstract boolean isTraceEnabled();
162
163    public abstract boolean isWarnEnabled();
164}