core/loggers/FileLogger.java

/* 
 * i-scream central monitoring system
 * http://www.i-scream.org.uk
 * Copyright (C) 2000-2002 i-scream
 * 
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

//---PACKAGE DECLARATION---
package uk.org.iscream.cms.server.core.loggers;

//---IMPORTS---
import uk.org.iscream.cms.util.*;
import uk.org.iscream.cms.server.core.*;
import java.util.Date;
import java.text.DateFormat;
import java.util.Locale;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

/**
 * The FileLogger is an implementation of the LoggerImpl defined
 * in the associated interface. It provides quite extensive features to allow
 * logging ot a text file.
 *
 * @author  $Author: tdb $
 * @version $Id: FileLogger.java,v 1.11 2002/05/21 16:47:17 tdb Exp $
 */
public class FileLogger implements LoggerImpl {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.11 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---

        /**
         * Creates a new FileLogger.
         *
         * The constructor checks that writing will be ok, then sets up the
         * writer. It makes use of the fileCheck() method found later on to
         * ensure writing will be ok, and throws an IOException if there is
         * a problem. Errors at this stage cannot be logged because the
         * logging mechanism has not be setup completely, so any problems
         * are printed to the screen in the same format used for logging.
         * 
         * @throws IOException if there is a problem with the file check.
         */
    public FileLogger() throws IOException{
        filename = System.getProperty("uk.org.iscream.cms.server.LoggerClass.FileLogger.filename");
                // Perform file check to make sure writing is ok
        if(!fileCheck()){
                        // Have to system.out.println errors because logging mechanism failed !
                        System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "File check failed, construction terminated"));
            throw new IOException("File check failed, unable to create FileLog");
        }
        try{
                        // Setup the writer
            writer = new BufferedWriter(new FileWriter(filename, true));
                        // File is now open
                        open = true;
        }
        catch(IOException e){
            System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Attempt to setup writer failed - " + e.getMessage()));
        }
                // Put an initial line into the log
        write(toString(), Logger.SYSINIT, "started");
    }

//---PUBLIC METHODS---
    
    /**
         * The write() method takes a line of text, pre-formatted
         * and outputs it using a method defined by the actual
         * implementation. The verbosity is given in case the
         * implementation wishes to utilise it in the layout -
         * eg. a different colour or font.
         * 
         * This instance writes the line to a file.
         *
         * @param line A line of formatted text to be logged
         * @param verbosity the verbosity of this message
         */  
    public synchronized void write(String line, int verbosity) {
                // Check to make sure file is open
                if(open){
                        // Produce a nicely formatted line for the logfile
                        try{
                                // We have to synchronize here due to problems with two write()'s being called before a newLine()
                                synchronized(writer){
                                        // Attempt to write the line
                                        writer.write(line);
                                        // Best to use newLine() as it will use the correct platform encoding
                                        writer.newLine();
                                }
                                // Make sure the line is written immeidiately
                                writer.flush();
                        }
                        catch(IOException e){
                                // We'd best log the error
                                System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Writing to logfile failed - " + e.getMessage()));
                                // As it's an IOException we should suspend logging
                                open = false;
                }
                }
                else{
                        // If file is not open we should print this to the screen
                        System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Write failed - file not open"));
                }
    }
 
        /**
         * The clear() method erases the contents of the logfile. It does
         * this in a very clumsy way - by closing the writer and opening a
         * new one which is set not to append. This results in the logfile
         * being overwritten, which effectively erases it.
         */
    public void clear(){
                // Check file is open
                if(open){
                        write(toString(), Logger.SYSMSG, "Attempting to clear logfile");
                        try{
                                // Close appending writer
                                open = false;
                                writer.close();
                                // Open a non-appending writer
                                writer = new BufferedWriter(new FileWriter(filename));
                                open = true;
                        }
                        catch(IOException e){
                                // We'd best log the error
                                write(toString(), Logger.ERROR, "Attempt to clear logfile failed - "+e.getMessage());
                                // As it's an IOException we should suspend logging
                                open = false;
                        }
                }
                else{
                        // If file is not open we should print this to the screen
                        System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Clearing failed - file not open"));
                }
    }
    
        /**
         * The close() method closes the logfile and no more data can be written.
         * If writing is attempted after close() has been called an error will be
         * generated. The open() method can be used to reopen or open a new file.
         */
    public void close(){
                // Check to see if a file is open
                if(open){
                        write(toString(), Logger.SYSMSG, "Attempting to terminate logging");
                        try{
                                open = false;
                        writer.close();         
                        }
                        catch(IOException e){
                                write(toString(), Logger.ERROR, "Attempt to close logfile failed - " + e.getMessage());
                                // As it's an IOException we should suspend logging
                                open = false;
                        }
                }
                else{
                        // If file is not open we should print this to the screen
                        System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Close failed - file not open"));
                }
    }
    
        /**
         * The open() method opens a new file after the close() method has
         * been called on the FileLog. This enables the user to easily change
         * the file to which the log is being written. An error is generated
         * if a file is already open.
         * 
         * @param filename The new file to write to.
         * @throws IOException if the file cannot be written to.
         */
        public void open(String filename) throws IOException{
                // Check to see if a file is open
                if(open){
                        // If file is already open then we should log that this went wrong
                        write(this.toString(), Logger.WARNING, "Open failed - a file is already open");
                }
                else{
                        this.filename = filename;
                        if(!fileCheck()) {
                                // Have to system.out.println errors because logging mechanism failed !
                                System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "File check failed, construction terminated"));
                                throw new IOException("File check failed, unable to create FileLog");
                        }
                        try{
                                // Setup the writer
                                writer = new BufferedWriter(new FileWriter(filename, true));
                                // File is now open
                                open = true;
                        }
                        catch(IOException e){
                            System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Attempt to open writer failed - " + e.getMessage()));
                        }
                }
        }

        /**
         * The suspend() method halts writing to the file by setting the open
         * boolean to false, and thus blocking the write() method. A line is
         * written to the logfile beforehand to note that writing has been
         * suspended.
         */
        public void suspend(){
                // Check to see if a file is open
                if(open){
                        // Make a note of the fact that writing has been suspended
                        write(toString(), Logger.SYSMSG, "Writing suspended");
                        // Make sure writing not permitted
                        open=false;
                }
                else{
                        // If file is not open we should print this to the screen
                        System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Suspend failed - file not open"));
                }
        }
        
        /**
         * The resume() method resumes writing to the file by setting the open
         * boolean to true. A line is written to the logfile to signify this
         * event occuring.
         */
        public void resume(){
                // Check to see if a file is open
                if(open){
                        // If file is open we should print this to the screen
                        System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Resume failed - file open"));
                }
                else{
                        // Permit writing again
                        open=true;
                        // Make a note of the fact that writing has been resumed
                        write(toString(), Logger.SYSMSG, "Writing resumed");
                }
        }
    
    /**
     * 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.cms.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 METHODS---

        /**
         * The fileCheck() method is used to ensure that writing is ok. It
         * performs so basic checks to make sure that if the file exists
         * it can be written to, and if not a new file is created. A boolean
         * result is returned to signify success or failure.
         * 
         * @return A boolean value signify whether the test was sucessful.
         */
    private boolean fileCheck(){
        boolean fileOK = false;
        try{
            File file = new File(filename);
                        
                        // File already exists
            if(file.exists()) {
                /* Only want success if it is a file (not a directory)
                                 * and can be written to.
                                 */
                                if(file.isFile() && file.canWrite()) {
                    fileOK = true;
                }
            }
                        // Create a new file and suceed
            else{
                file.createNewFile();
                fileOK = true;
            }
        }
        catch(IOException e){
            System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "File check failed - "+e.getMessage()));
        }
        
        return fileOK;
    }

    /**
     * This method is provided if this class wishes to log
     * a message itself.
     *
         * @param source A String representation of the source
         * @param verbosity the verbosity of this message
         * @param message The message to log
         */  
    private void write(String source, int verbosity, String message) {
        write(FormatName.formatLogLine(source, verbosity, message), verbosity);
    }

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

//---ATTRIBUTES---

        /**
         * The filename of the currently open, or last open, file.
         */
    private String filename;
        
        /**
         * A reference to the writer being used.
         */
    private BufferedWriter writer;
        
        /**
         * A boolean signifying whether a file is open or not.
         */
        private boolean open = false;
        
        /**
     * 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 = Core.NAME;

//---STATIC ATTRIBUTES---
    
}
Revision:	1.12
Committed:	Wed Feb 5 16:43:47 2003 UTC (21 years, 3 months ago) by tdb
Branch:	MAIN
Changes since 1.11:	+4 -4 lines
Log Message:	Changed the server to use the external util package. Quite a minor change, but does affect a lot of files.
#	Content
1	/*
2	* i-scream central monitoring system
3	* http://www.i-scream.org.uk
4	* Copyright (C) 2000-2002 i-scream
5	*
6	* This program is free software; you can redistribute it and/or
7	* modify it under the terms of the GNU General Public License
8	* as published by the Free Software Foundation; either version 2
9	* of the License, or (at your option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the GNU General Public License
17	* along with this program; if not, write to the Free Software
18	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19	*/
20
21	//---PACKAGE DECLARATION---
22	package uk.org.iscream.cms.server.core.loggers;
23
24	//---IMPORTS---
25	import uk.org.iscream.cms.util.*;
26	import uk.org.iscream.cms.server.core.*;
27	import java.util.Date;
28	import java.text.DateFormat;
29	import java.util.Locale;
30	import java.io.BufferedWriter;
31	import java.io.File;
32	import java.io.FileWriter;
33	import java.io.IOException;
34
35	/**
36	* The FileLogger is an implementation of the LoggerImpl defined
37	* in the associated interface. It provides quite extensive features to allow
38	* logging ot a text file.
39	*
40	* @author $Author: tdb $
41	* @version $Id: FileLogger.java,v 1.11 2002/05/21 16:47:17 tdb Exp $
42	*/
43	public class FileLogger implements LoggerImpl {
44
45	//---FINAL ATTRIBUTES---
46
47	/**
48	* The current CVS revision of this class
49	*/
50	public final String REVISION = "$Revision: 1.11 $";
51
52	//---STATIC METHODS---
53
54	//---CONSTRUCTORS---
55
56	/**
57	* Creates a new FileLogger.
58	*
59	* The constructor checks that writing will be ok, then sets up the
60	* writer. It makes use of the fileCheck() method found later on to
61	* ensure writing will be ok, and throws an IOException if there is
62	* a problem. Errors at this stage cannot be logged because the
63	* logging mechanism has not be setup completely, so any problems
64	* are printed to the screen in the same format used for logging.
65	*
66	* @throws IOException if there is a problem with the file check.
67	*/
68	public FileLogger() throws IOException{
69	filename = System.getProperty("uk.org.iscream.cms.server.LoggerClass.FileLogger.filename");
70	// Perform file check to make sure writing is ok
71	if(!fileCheck()){
72	// Have to system.out.println errors because logging mechanism failed !
73	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "File check failed, construction terminated"));
74	throw new IOException("File check failed, unable to create FileLog");
75	}
76	try{
77	// Setup the writer
78	writer = new BufferedWriter(new FileWriter(filename, true));
79	// File is now open
80	open = true;
81	}
82	catch(IOException e){
83	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Attempt to setup writer failed - " + e.getMessage()));
84	}
85	// Put an initial line into the log
86	write(toString(), Logger.SYSINIT, "started");
87	}
88
89	//---PUBLIC METHODS---
90
91	/**
92	* The write() method takes a line of text, pre-formatted
93	* and outputs it using a method defined by the actual
94	* implementation. The verbosity is given in case the
95	* implementation wishes to utilise it in the layout -
96	* eg. a different colour or font.
97	*
98	* This instance writes the line to a file.
99	*
100	* @param line A line of formatted text to be logged
101	* @param verbosity the verbosity of this message
102	*/
103	public synchronized void write(String line, int verbosity) {
104	// Check to make sure file is open
105	if(open){
106	// Produce a nicely formatted line for the logfile
107	try{
108	// We have to synchronize here due to problems with two write()'s being called before a newLine()
109	synchronized(writer){
110	// Attempt to write the line
111	writer.write(line);
112	// Best to use newLine() as it will use the correct platform encoding
113	writer.newLine();
114	}
115	// Make sure the line is written immeidiately
116	writer.flush();
117	}
118	catch(IOException e){
119	// We'd best log the error
120	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Writing to logfile failed - " + e.getMessage()));
121	// As it's an IOException we should suspend logging
122	open = false;
123	}
124	}
125	else{
126	// If file is not open we should print this to the screen
127	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Write failed - file not open"));
128	}
129	}
130
131	/**
132	* The clear() method erases the contents of the logfile. It does
133	* this in a very clumsy way - by closing the writer and opening a
134	* new one which is set not to append. This results in the logfile
135	* being overwritten, which effectively erases it.
136	*/
137	public void clear(){
138	// Check file is open
139	if(open){
140	write(toString(), Logger.SYSMSG, "Attempting to clear logfile");
141	try{
142	// Close appending writer
143	open = false;
144	writer.close();
145	// Open a non-appending writer
146	writer = new BufferedWriter(new FileWriter(filename));
147	open = true;
148	}
149	catch(IOException e){
150	// We'd best log the error
151	write(toString(), Logger.ERROR, "Attempt to clear logfile failed - "+e.getMessage());
152	// As it's an IOException we should suspend logging
153	open = false;
154	}
155	}
156	else{
157	// If file is not open we should print this to the screen
158	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Clearing failed - file not open"));
159	}
160	}
161
162	/**
163	* The close() method closes the logfile and no more data can be written.
164	* If writing is attempted after close() has been called an error will be
165	* generated. The open() method can be used to reopen or open a new file.
166	*/
167	public void close(){
168	// Check to see if a file is open
169	if(open){
170	write(toString(), Logger.SYSMSG, "Attempting to terminate logging");
171	try{
172	open = false;
173	writer.close();
174	}
175	catch(IOException e){
176	write(toString(), Logger.ERROR, "Attempt to close logfile failed - " + e.getMessage());
177	// As it's an IOException we should suspend logging
178	open = false;
179	}
180	}
181	else{
182	// If file is not open we should print this to the screen
183	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Close failed - file not open"));
184	}
185	}
186
187	/**
188	* The open() method opens a new file after the close() method has
189	* been called on the FileLog. This enables the user to easily change
190	* the file to which the log is being written. An error is generated
191	* if a file is already open.
192	*
193	* @param filename The new file to write to.
194	* @throws IOException if the file cannot be written to.
195	*/
196	public void open(String filename) throws IOException{
197	// Check to see if a file is open
198	if(open){
199	// If file is already open then we should log that this went wrong
200	write(this.toString(), Logger.WARNING, "Open failed - a file is already open");
201	}
202	else{
203	this.filename = filename;
204	if(!fileCheck()) {
205	// Have to system.out.println errors because logging mechanism failed !
206	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "File check failed, construction terminated"));
207	throw new IOException("File check failed, unable to create FileLog");
208	}
209	try{
210	// Setup the writer
211	writer = new BufferedWriter(new FileWriter(filename, true));
212	// File is now open
213	open = true;
214	}
215	catch(IOException e){
216	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Attempt to open writer failed - " + e.getMessage()));
217	}
218	}
219	}
220
221	/**
222	* The suspend() method halts writing to the file by setting the open
223	* boolean to false, and thus blocking the write() method. A line is
224	* written to the logfile beforehand to note that writing has been
225	* suspended.
226	*/
227	public void suspend(){
228	// Check to see if a file is open
229	if(open){
230	// Make a note of the fact that writing has been suspended
231	write(toString(), Logger.SYSMSG, "Writing suspended");
232	// Make sure writing not permitted
233	open=false;
234	}
235	else{
236	// If file is not open we should print this to the screen
237	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Suspend failed - file not open"));
238	}
239	}
240
241	/**
242	* The resume() method resumes writing to the file by setting the open
243	* boolean to true. A line is written to the logfile to signify this
244	* event occuring.
245	*/
246	public void resume(){
247	// Check to see if a file is open
248	if(open){
249	// If file is open we should print this to the screen
250	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "Resume failed - file open"));
251	}
252	else{
253	// Permit writing again
254	open=true;
255	// Make a note of the fact that writing has been resumed
256	write(toString(), Logger.SYSMSG, "Writing resumed");
257	}
258	}
259
260	/**
261	* Overrides the {@link java.lang.Object#toString() Object.toString()}
262	* method to provide clean logging (every class should have this).
263	*
264	* This uses the uk.org.iscream.cms.util.FormatName class
265	* to format the toString()
266	*
267	* @return the name of this class and its CVS revision
268	*/
269	public String toString() {
270	return FormatName.getName(
271	_name,
272	getClass().getName(),
273	REVISION);
274	}
275
276	//---PRIVATE METHODS---
277
278	/**
279	* The fileCheck() method is used to ensure that writing is ok. It
280	* performs so basic checks to make sure that if the file exists
281	* it can be written to, and if not a new file is created. A boolean
282	* result is returned to signify success or failure.
283	*
284	* @return A boolean value signify whether the test was sucessful.
285	*/
286	private boolean fileCheck(){
287	boolean fileOK = false;
288	try{
289	File file = new File(filename);
290
291	// File already exists
292	if(file.exists()) {
293	/* Only want success if it is a file (not a directory)
294	* and can be written to.
295	*/
296	if(file.isFile() && file.canWrite()) {
297	fileOK = true;
298	}
299	}
300	// Create a new file and suceed
301	else{
302	file.createNewFile();
303	fileOK = true;
304	}
305	}
306	catch(IOException e){
307	System.out.println(FormatName.formatLogLine(this.toString(), Logger.FATAL, "File check failed - "+e.getMessage()));
308	}
309
310	return fileOK;
311	}
312
313	/**
314	* This method is provided if this class wishes to log
315	* a message itself.
316	*
317	* @param source A String representation of the source
318	* @param verbosity the verbosity of this message
319	* @param message The message to log
320	*/
321	private void write(String source, int verbosity, String message) {
322	write(FormatName.formatLogLine(source, verbosity, message), verbosity);
323	}
324
325	//---ACCESSOR/MUTATOR METHODS---
326
327	//---ATTRIBUTES---
328
329	/**
330	* The filename of the currently open, or last open, file.
331	*/
332	private String filename;
333
334	/**
335	* A reference to the writer being used.
336	*/
337	private BufferedWriter writer;
338
339	/**
340	* A boolean signifying whether a file is open or not.
341	*/
342	private boolean open = false;
343
344	/**
345	* This is the friendly identifier of the
346	* component this class is running in.
347	* eg, a Filter may be called "filter1",
348	* If this class does not have an owning
349	* component, a name from the configuration
350	* can be placed here. This name could also
351	* be changed to null for utility classes.
352	*/
353	private String _name = Core.NAME;
354
355	//---STATIC ATTRIBUTES---
356
357	}