experimental/agents/Logger.java

//---PACKAGE DECLARATION---
//package uk.org.iscream.core;

//---IMPORTS---
//import uk.org.iscream.util.*;

/**
 * Allows classes to send logging information
 * to an implementation of the LoggerImpl interface.
 *
 * @author  $Author: tdb1 $
 * @version $Id: LoggerServant.java,v 1.9 2001/03/14 23:25:29 tdb1 Exp $
 */
class Logger {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.9 $";
    
    /**
     * The verbosity value for the FATAL log message
     */
    public static final int FATAL = 0;
    
    /**
     * The verbosity value for the ERROR log message
     */
    public static final int ERROR = 1;
    
    /**
     * The verbosity value for the WARNING log message
     */
    public static final int WARNING = 2;
    
    /**
     * The verbosity value for the SYSMSG log message
     */
    public static final int SYSMSG = 3;
    
    /**
     * The verbosity value for the SYSINIT log message
     */
    public static final int SYSINIT = 4;
    
    /**
     * The verbosity value for the DEBUG log message
     */
    public static final int DEBUG = 5;
    
    /**
     * An array of names of verbosity levels.
     * Thus logging messages are now "classed" by the level"
     * This string is prepended to the "source" of a logging message.
     */
    public final static String[] VERBOSITY_NAMES = {"FATAL", "ERROR", "WARNING", "SYSMSG", "SYSINIT", "DEBUG"};
    
//---STATIC METHODS---

    /**
     * Returns a reference to the singleton logger in use
     *
     * @throws RuntimeException if not yet initialised
     */
    public static Logger getInstance() throws RuntimeException {
        if (_instance == null) {
                throw new RuntimeException("Cannot obtain instance to uninitialised Logger");
        }
        return _instance;
    }

    /**
     * Constructs and returns the singleton Logger class
     *
     * @param logger a reference to the LoggerImpl this will use
     * @param verbosityLevel the system wide verbosity level in use
     *
     * @throws RuntimeException if already initialised
     */
    public static Logger initialise(LoggerImpl logger, int verbosityLevel) throws RuntimeException {
        if (_instance != null) {
            throw new RuntimeException("Already initialised!");
        }
        _instance = new Logger(logger, verbosityLevel);
        return _instance;
    }
    
//---CONSTRUCTORS---

    /**
     * Creates a new Logger with a given logging implementation
     * and a given verbosity level.
     * This is a private method to ensure singleton pattern.
     *
     * @param logger a reference to the LoggerImpl this will use
     * @param verbosityLevel the system wide verbosity level in use
     */
    private Logger(LoggerImpl logger, int verbosityLevel) {
        _logger = logger;
        _verbosityLevel = verbosityLevel;
        write(toString(), Logger.SYSINIT, "started");
        write(toString(), Logger.SYSMSG, "using verbosity " + _verbosityLevel);
    }

//---PUBLIC METHODS---

    /**
         * The write() method takes a source, verbosity level and
         * message, and formats them using an external line
         * formatting method. This line is then given to the logger
         * to be written. Note that checking of the level is carried
         * out here.
         * 
         * @param source A string representation of the calling object.
         * @param verbosity the verbosity of this message
         * @param message The text to be logged.
         */   
    public void write(String source, int verbosity, String message) {
        if (verbosity <= _verbosityLevel) {
            _logger.write(FormatName.formatLogLine(source, verbosity, message), verbosity);
        }
    }
       
    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * This uses the uk.org.iscream.util.FormatName class
     * to format the toString()
     *
     * @return the name of this class and its CVS revision
     */
    public String toString() {
        return FormatName.getName(
            _name,
            getClass().getName(),
            REVISION);
    }
    
//---PRIVATE/PROTECTED METHODS---

//---ACCESSOR/MUTATOR METHODS---

//---ATTRIBUTES---

        /**
         * The verbosity level of this instance
         */
        private int _verbosityLevel;
        
        /**
         * The actual Logger used by this instance
         */
        private LoggerImpl _logger;
    
    /**
     * This is the friendly identifier of the
     * component this class is running in.
     * eg, a Filter may be called "filter1",
     * If this class does not have an owning
     * component,  a name from the configuration
     * can be placed here.  This name could also
     * be changed to null for utility classes.
     */
    private String _name = "Logger";
    
//---STATIC ATTRIBUTES---
    
    /**
     * Holds the reference to the singleton instance of his class
     */
    private static Logger _instance;
    
}
Revision:	1.1
Committed:	Fri May 4 02:04:35 2001 UTC (23 years, 7 months ago) by ajm
Branch:	MAIN
CVS Tags:	HEAD
Log Message:	Loads of new framework but far from complete. The BasicAgent class is as it says, a basic agent, with ability to be run from the command line to fire it into an agentstation. AgentStations now have support for adding and removing agents and support for multiple listeners. Also initial support for peer agent stations. Attempted support at peer -> peer agent transfer, but run into problems. Still no bytecode transfer, but location and method has been figured out. The AgentSystem class is now the bootstrap class for an agent station. It brings up the AgentStation (which is now singleton) and the Logger (also singleton - using standard i-scream logging techniques). It is possible to specify a peer station that the booting agent station should connect to. Initial TODO: agent class loader agent bytecode transfer solve peer -> peer problems - possibly by creating extra socket to send agent, but shouldn't really be needed
#	Content
1	//---PACKAGE DECLARATION---
2	//package uk.org.iscream.core;
3
4	//---IMPORTS---
5	//import uk.org.iscream.util.*;
6
7	/**
8	* Allows classes to send logging information
9	* to an implementation of the LoggerImpl interface.
10	*
11	* @author $Author: tdb1 $
12	* @version $Id: LoggerServant.java,v 1.9 2001/03/14 23:25:29 tdb1 Exp $
13	*/
14	class Logger {
15
16	//---FINAL ATTRIBUTES---
17
18	/**
19	* The current CVS revision of this class
20	*/
21	public final String REVISION = "$Revision: 1.9 $";
22
23	/**
24	* The verbosity value for the FATAL log message
25	*/
26	public static final int FATAL = 0;
27
28	/**
29	* The verbosity value for the ERROR log message
30	*/
31	public static final int ERROR = 1;
32
33	/**
34	* The verbosity value for the WARNING log message
35	*/
36	public static final int WARNING = 2;
37
38	/**
39	* The verbosity value for the SYSMSG log message
40	*/
41	public static final int SYSMSG = 3;
42
43	/**
44	* The verbosity value for the SYSINIT log message
45	*/
46	public static final int SYSINIT = 4;
47
48	/**
49	* The verbosity value for the DEBUG log message
50	*/
51	public static final int DEBUG = 5;
52
53	/**
54	* An array of names of verbosity levels.
55	* Thus logging messages are now "classed" by the level"
56	* This string is prepended to the "source" of a logging message.
57	*/
58	public final static String[] VERBOSITY_NAMES = {"FATAL", "ERROR", "WARNING", "SYSMSG", "SYSINIT", "DEBUG"};
59
60	//---STATIC METHODS---
61
62	/**
63	* Returns a reference to the singleton logger in use
64	*
65	* @throws RuntimeException if not yet initialised
66	*/
67	public static Logger getInstance() throws RuntimeException {
68	if (_instance == null) {
69	throw new RuntimeException("Cannot obtain instance to uninitialised Logger");
70	}
71	return _instance;
72	}
73
74	/**
75	* Constructs and returns the singleton Logger class
76	*
77	* @param logger a reference to the LoggerImpl this will use
78	* @param verbosityLevel the system wide verbosity level in use
79	*
80	* @throws RuntimeException if already initialised
81	*/
82	public static Logger initialise(LoggerImpl logger, int verbosityLevel) throws RuntimeException {
83	if (_instance != null) {
84	throw new RuntimeException("Already initialised!");
85	}
86	_instance = new Logger(logger, verbosityLevel);
87	return _instance;
88	}
89
90	//---CONSTRUCTORS---
91
92	/**
93	* Creates a new Logger with a given logging implementation
94	* and a given verbosity level.
95	* This is a private method to ensure singleton pattern.
96	*
97	* @param logger a reference to the LoggerImpl this will use
98	* @param verbosityLevel the system wide verbosity level in use
99	*/
100	private Logger(LoggerImpl logger, int verbosityLevel) {
101	_logger = logger;
102	_verbosityLevel = verbosityLevel;
103	write(toString(), Logger.SYSINIT, "started");
104	write(toString(), Logger.SYSMSG, "using verbosity " + _verbosityLevel);
105	}
106
107	//---PUBLIC METHODS---
108
109	/**
110	* The write() method takes a source, verbosity level and
111	* message, and formats them using an external line
112	* formatting method. This line is then given to the logger
113	* to be written. Note that checking of the level is carried
114	* out here.
115	*
116	* @param source A string representation of the calling object.
117	* @param verbosity the verbosity of this message
118	* @param message The text to be logged.
119	*/
120	public void write(String source, int verbosity, String message) {
121	if (verbosity <= _verbosityLevel) {
122	_logger.write(FormatName.formatLogLine(source, verbosity, message), verbosity);
123	}
124	}
125
126	/**
127	* Overrides the {@link java.lang.Object#toString() Object.toString()}
128	* method to provide clean logging (every class should have this).
129	*
130	* This uses the uk.org.iscream.util.FormatName class
131	* to format the toString()
132	*
133	* @return the name of this class and its CVS revision
134	*/
135	public String toString() {
136	return FormatName.getName(
137	_name,
138	getClass().getName(),
139	REVISION);
140	}
141
142	//---PRIVATE/PROTECTED METHODS---
143
144	//---ACCESSOR/MUTATOR METHODS---
145
146	//---ATTRIBUTES---
147
148	/**
149	* The verbosity level of this instance
150	*/
151	private int _verbosityLevel;
152
153	/**
154	* The actual Logger used by this instance
155	*/
156	private LoggerImpl _logger;
157
158	/**
159	* This is the friendly identifier of the
160	* component this class is running in.
161	* eg, a Filter may be called "filter1",
162	* If this class does not have an owning
163	* component, a name from the configuration
164	* can be placed here. This name could also
165	* be changed to null for utility classes.
166	*/
167	private String _name = "Logger";
168
169	//---STATIC ATTRIBUTES---
170
171	/**
172	* Holds the reference to the singleton instance of his class
173	*/
174	private static Logger _instance;
175
176	}