Tomcat example source code file (FileHandler.java)

This example Tomcat source code file (FileHandler.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

classloader, errormanager, exception, exception, file, filehandler, filehandler, handler, io, jdbc, log, logging, printwriter, printwriter, simpleformatter, sql, string, string, timestamp

The Tomcat FileHandler.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


package org.apache.juli;

import java.io.File;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.sql.Timestamp;
import java.util.logging.ErrorManager;
import java.util.logging.Filter;
import java.util.logging.Formatter;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogManager;
import java.util.logging.LogRecord;
import java.util.logging.SimpleFormatter;

/**
 * Implementation of <b>Handler that appends log messages to a file
 * named {prefix}.{date}.{suffix} in a configured directory, with an
 * optional preceding timestamp.
 *
 * @version $Revision: 483782 $ $Date: 2006-12-08 03:24:30 +0100 (ven., 08 déc. 2006) $
 */

public class FileHandler
    extends Handler {


    // ------------------------------------------------------------ Constructor

    
    public FileHandler() {
        this(null, null, null);
    }
    
    
    public FileHandler(String directory, String prefix, String suffix) {
        this.directory = directory;
        this.prefix = prefix;
        this.suffix = suffix;
        configure();
        open();
    }
    

    // ----------------------------------------------------- Instance Variables


    /**
     * The as-of date for the currently open log file, or a zero-length
     * string if there is no open log file.
     */
    private String date = "";


    /**
     * The directory in which log files are created.
     */
    private String directory = null;


    /**
     * The prefix that is added to log file filenames.
     */
    private String prefix = null;


    /**
     * The suffix that is added to log file filenames.
     */
    private String suffix = null;


    /**
     * The PrintWriter to which we are currently logging, if any.
     */
    private PrintWriter writer = null;


    // --------------------------------------------------------- Public Methods


    /**
     * Format and publish a <tt>LogRecord.
     *
     * @param  record  description of the log event
     */
    public void publish(LogRecord record) {

        if (!isLoggable(record)) {
            return;
        }

        // Construct the timestamp we will use, if requested
        Timestamp ts = new Timestamp(System.currentTimeMillis());
        String tsString = ts.toString().substring(0, 19);
        String tsDate = tsString.substring(0, 10);

        // If the date has changed, switch log files
        if (!date.equals(tsDate)) {
            synchronized (this) {
                if (!date.equals(tsDate)) {
                    close();
                    date = tsDate;
                    open();
                }
            }
        }

        String result = null;
        try {
            result = getFormatter().format(record);
        } catch (Exception e) {
            reportError(null, e, ErrorManager.FORMAT_FAILURE);
            return;
        }
        
        try {
            writer.write(result);
            writer.flush();
        } catch (Exception e) {
            reportError(null, e, ErrorManager.WRITE_FAILURE);
            return;
        }
        
    }
    
    
    // -------------------------------------------------------- Private Methods


    /**
     * Close the currently open log file (if any).
     */
    public void close() {
        
        try {
            if (writer == null)
                return;
            writer.write(getFormatter().getTail(this));
            writer.flush();
            writer.close();
            writer = null;
            date = "";
        } catch (Exception e) {
            reportError(null, e, ErrorManager.CLOSE_FAILURE);
        }
        
    }


    /**
     * Flush the writer.
     */
    public void flush() {

        try {
            writer.flush();
        } catch (Exception e) {
            reportError(null, e, ErrorManager.FLUSH_FAILURE);
        }
        
    }
    
    
    /**
     * Configure from <code>LogManager properties.
     */
    private void configure() {

        Timestamp ts = new Timestamp(System.currentTimeMillis());
        String tsString = ts.toString().substring(0, 19);
        date = tsString.substring(0, 10);

        String className = FileHandler.class.getName();
        
        ClassLoader cl = Thread.currentThread().getContextClassLoader();
        
        // Retrieve configuration of logging file name
        if (directory == null)
            directory = getProperty(className + ".directory", "logs");
        if (prefix == null)
            prefix = getProperty(className + ".prefix", "juli.");
        if (suffix == null)
            suffix = getProperty(className + ".suffix", ".log");

        // Get logging level for the handler
        setLevel(Level.parse(getProperty(className + ".level", "" + Level.ALL)));

        // Get filter configuration
        String filterName = getProperty(className + ".filter", null);
        if (filterName != null) {
            try {
                setFilter((Filter) cl.loadClass(filterName).newInstance());
            } catch (Exception e) {
                // Ignore
            }
        }

        // Set formatter
        String formatterName = getProperty(className + ".formatter", null);
        if (formatterName != null) {
            try {
                setFormatter((Formatter) cl.loadClass(formatterName).newInstance());
            } catch (Exception e) {
                // Ignore
            }
        } else {
            setFormatter(new SimpleFormatter());
        }
        
        // Set error manager
        setErrorManager(new ErrorManager());
        
    }

    
    private String getProperty(String name, String defaultValue) {
        String value = LogManager.getLogManager().getProperty(name);
        if (value == null) {
            value = defaultValue;
        } else {
            value = value.trim();
        }
        return value;
    }
    
    
    /**
     * Open the new log file for the date specified by <code>date.
     */
    private void open() {

        // Create the directory if necessary
        File dir = new File(directory);
        dir.mkdirs();

        // Open the current log file
        try {
            String pathname = dir.getAbsolutePath() + File.separator +
                prefix + date + suffix;
            writer = new PrintWriter(new FileWriter(pathname, true), true);
            writer.write(getFormatter().getHead(this));
        } catch (Exception e) {
            reportError(null, e, ErrorManager.OPEN_FAILURE);
            writer = null;
        }

    }


}