001/*
002 * jPOS Project [http://jpos.org]
003 * Copyright (C) 2000-2026 jPOS Software SRL
004 *
005 * This program is free software: you can redistribute it and/or modify
006 * it under the terms of the GNU Affero General Public License as
007 * published by the Free Software Foundation, either version 3 of the
008 * License, or (at your option) any later version.
009 *
010 * This program is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
013 * GNU Affero General Public License for more details.
014 *
015 * You should have received a copy of the GNU Affero General Public License
016 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
017 */
018
019package org.jpos.util;
020
021import org.jpos.core.Configurable;
022import org.jpos.core.Configuration;
023import org.jpos.core.ConfigurationException;
024import org.jpos.q2.Q2;
025
026import java.util.ArrayList;
027import java.util.Collections;
028import java.util.ConcurrentModificationException;
029import java.util.Iterator;
030import java.util.List;
031
032/**
033 * Peer class Logger forwards LogEvents generated by LogSources 
034 * to LogListeners.
035 * <br>
036 * This little <a href="/doc/LoggerGuide.html">tutorial</a>
037 * give you additional information on how to extend the jPOS's
038 * Logger subsystem.
039 *
040 * @author apr@cs.com.uy
041 * @version $Id$
042 * @see LogEvent
043 * @see LogSource
044 * @see LogListener
045 * @see Loggeable
046 * @see SimpleLogListener
047 * @see RotateLogListener
048 */
049@SuppressWarnings("unchecked")
050public class Logger implements LogProducer,Configurable
051{
052    Configuration cfg;
053    String name;
054    List<LogListener> listeners;
055    /** Prefix used to register loggers in {@code NameRegistrar}. */
056    public static final String NRPREFIX = "logger.";
057
058    /** Default constructor. */
059    public Logger () {
060        super();
061        listeners = Collections.synchronizedList(new ArrayList<>());
062        name = "";
063    }
064
065    /** Returns the current configuration.
066     * @return configuration object
067     */
068    public Configuration getConfiguration()
069    {
070        return cfg;
071    }
072
073    @Override
074    /** Configures this Logger instance.
075     * @param cfg the new configuration
076     * @throws ConfigurationException on configuration error
077     */
078    public void setConfiguration(Configuration cfg) throws ConfigurationException
079    {
080        this.cfg = cfg;
081    }
082
083    /** Adds a log listener to this logger.
084     * @param l the listener to add
085     */
086    public void addListener (LogListener l) {
087        listeners.add(l);
088    }
089    public void removeListener (LogListener l) {
090        listeners.remove(l);
091    }
092    public void removeAllListeners () {
093        for (Object l : listeners) {
094            if (l instanceof Destroyable) {
095                ((Destroyable) l).destroy();
096            }
097        }
098        listeners.clear ();
099    }
100    /** Dispatches a log event to the appropriate logger and its listeners.
101     * @param evt the log event to dispatch
102     */
103    public static void log (LogEvent evt) {
104        Logger l = null;
105        LogSource source = evt.getSource();
106        if (source != null)
107            l = source.getLogger();
108        if (l == null && !evt.isHonorSourceLogger()) {
109            l = getLogger(Q2.LOGGER_NAME);
110        }
111        if (l != null && l.hasListeners ()) {
112            Iterator<LogListener> i = l.listeners.iterator();
113            while (i.hasNext() && evt != null) {
114                try {
115                    evt = i.next().log(evt);
116                } catch (ConcurrentModificationException e) {
117                    break;
118                } catch (Throwable t) {
119                    evt.addMessage (t);
120                }
121            }
122        }
123    }
124    /**
125     * associates this Logger with a name using NameRegistrar
126     * @param name name to register
127     * @see NameRegistrar
128     */
129    public void setName (String name) {
130        this.name = name;
131        NameRegistrar.register (NRPREFIX+name, this);
132    }
133    /**
134     * destroy logger
135     */
136    public void destroy () {
137        NameRegistrar.unregister (NRPREFIX+name);
138        removeAllListeners ();
139    }
140    /**
141     * Returns the logger instance registered under the given name, creating one if necessary.
142     * @param name the logger name
143     * @return logger instance with given name. Creates one if necessary
144     * @see NameRegistrar
145     */
146    public synchronized static Logger getLogger (String name) {
147        Logger l;
148        try {
149            l = NameRegistrar.get (NRPREFIX+name);
150        } catch (NameRegistrar.NotFoundException e) {
151            l = new Logger();
152            l.setName (name);
153        }
154        return l;
155    }
156    /**
157     * Returns this logger's registered name.
158     * @return this logger's name ("" if no name was set)
159     */
160    public String getName() {
161        return this.name;
162    }
163    /**
164     * Used by heavy used methods to avoid LogEvent creation 
165     * @return true if Logger has associated LogListsners
166     */
167    public boolean hasListeners() {
168        return !listeners.isEmpty();
169    }
170}