timesizerollingfileappender.java

《JSP网站开发典型模块与实例精讲》一书光盘源码

                break;
            case TOP_OF_DAY:
                LogLog.debug("Appender [" + name
                             + "] to be rolled at midnight.");
                break;
            case TOP_OF_WEEK:
                LogLog.debug("Appender [" + name
                             + "] to be rolled at start of week.");
                break;
            case TOP_OF_MONTH:
                LogLog.debug("Appender [" + name
                             + "] to be rolled at start of every month.");
                break;
            default:
                LogLog.warn("Unknown periodicity for appender [" + name + "].");
        }
    }

    // This method computes the roll over period by looping over the
    // periods, starting with the shortest, and stopping when the r0 is
    // different from from r1, where r0 is the epoch formatted according
    // the datePattern (supplied by the user) and r1 is the
    // epoch+nextMillis(i) formatted according to datePattern. All date
    // formatting is done in GMT and not local format because the test
    // logic is based on comparisons relative to 1970-01-01 00:00:00
    // GMT (the epoch).

    int computeCheckPeriod() {
        RollingCalendar rollingCalendar = new RollingCalendar(gmtTimeZone,
            Locale.ENGLISH);
        // set sate to 1970-01-01 00:00:00 GMT
        Date epoch = new Date(0);
        if (datePattern != null) {
            for (int i = TOP_OF_MINUTE; i <= TOP_OF_MONTH; i++) {
                SimpleDateFormat simpleDateFormat = new SimpleDateFormat(
                    datePattern);
                simpleDateFormat.setTimeZone(gmtTimeZone); // do all date formatting in GMT
                String r0 = simpleDateFormat.format(epoch);
                rollingCalendar.setType(i);
                Date next = new Date(rollingCalendar.getNextCheckMillis(epoch));
                String r1 = simpleDateFormat.format(next);
                LogLog.debug("Type = " + i + ", r0 = " + r0 + ", r1 = " + r1);
                if (r0 != null && r1 != null && !r0.equals(r1)) {
                    return i;
                }
            }
        }
        return TOP_OF_TROUBLE; // Deliberately head for trouble...
    }

    /**
     Rollover the current file to a new file.
     * @throws java.io.IOException
     */
    public void rollOverForTime() throws IOException {
        String LOG_BACKUP_SUFFIX = ".bak";

        /* Compute filename, but only if datePattern is specified */
        if (datePattern == null) {
            errorHandler.error("Missing DatePattern option in rollOver().");
            return;
        }

        String datedFilename = fileName + sdf.format(now);
        LogLog.debug("datedFilename:" + datedFilename);
        // It is too early to roll over because we are still within the
        // bounds of the current interval. Rollover will occur once the
        // next interval is reached.
        if (scheduledFilename.equals(datedFilename)) {
            return;
        }

        // close current file, and rename it to datedFilename
        this.closeFile();

        File target = new File(scheduledFilename
                               + LOG_BACKUP_SUFFIX);
        if (target.exists()) {
            target.delete();
        }

        File file = new File(fileName);
        for (int i = 1; i <= maxBackupIndex; i++) { //roll for all size-backup files
            String before = fileName + "." + i;
            File files = new File(before);
            String after = scheduledFilename + "." + i
                + LOG_BACKUP_SUFFIX;
            File targets = new File(after);
            if (targets.exists()) {
                targets.delete();
            }
            if (files.exists()) { //only backup existed one
                boolean result = files.renameTo(targets);
                if (result) {
                    LogLog.debug(before + " -> " + after);
                }
                else {
                    LogLog.error("Failed to rename [" + before + "] to ["
                                 + after + "].");
                }
            }
        }

        //rename current writting file is necessary
        boolean result = file.renameTo(target);
        if (result) {
            LogLog.debug(fileName + " -> " + scheduledFilename);
        }
        else {
            LogLog.error("Failed to rename [" + fileName + "] to ["
                         + scheduledFilename + "].");
        }

        try {
            // This will also close the file. This is OK since multiple
            // close operations are safe.
            this.setFile(fileName, false, this.bufferedIO, this.bufferSize);
        }
        catch (IOException e) {
            errorHandler.error("setFile(" + fileName + ", false) call failed.");
        }
        scheduledFilename = datedFilename;
        LogLog.debug("scheduledFilename after roll:" + scheduledFilename);
    }

    /**
     Implements the usual roll over behaviour.
     <p>If <code>MaxBackupIndex</code> is positive, then files
     {<code>File.1</code>, ..., <code>File.MaxBackupIndex -1</code>}
     are renamed to {<code>File.2</code>, ...,
     <code>File.MaxBackupIndex</code>}. Moreover, <code>File</code> is
     renamed <code>File.1</code> and closed. A new <code>File</code> is
     created to receive further log output.
     <p>If <code>MaxBackupIndex</code> is equal to zero, then the
     <code>File</code> is truncated with no backup files created.
     */
    public // synchronization not necessary since doAppend is alreasy synched
        void rollOverForSize() {
        File target;
        File file;

        LogLog.debug("rolling over count="
                     + ( (CountingQuietWriter) qw).getCount());
        LogLog.debug("maxBackupIndex=" + maxBackupIndex);
        // If maxBackups <= 0, then there is no file renaming to be done.
        if (maxBackupIndex > 0) {
            // Delete the oldest file, to keep Windows happy.
            file = new File(fileName + '.' + maxBackupIndex);
            if (file.exists()) {
                file.delete();

                // Map {(maxBackupIndex - 1), ..., 2, 1} to {maxBackupIndex, ..., 3, 2}
            }
            for (int i = maxBackupIndex - 1; i >= 1; i--) {
                file = new File(fileName + "." + i);
                if (file.exists()) {
                    target = new File(fileName + '.' + (i + 1));
                    LogLog.debug("Renaming file " + file + " to " + target);
                    file.renameTo(target);
                }
            }

            // Rename fileName to fileName.1
            target = new File(fileName + "." + 1);

            this.closeFile(); // keep windows happy.

            file = new File(fileName);
            LogLog.debug("Renaming file " + file + " to " + target);
            file.renameTo(target);
        }

        try {
            // This will also close the file. This is OK since multiple
            // close operations are safe.
            this.setFile(fileName, false, bufferedIO, bufferSize);
        }
        catch (IOException e) {
            LogLog.error("setFile(" + fileName + ", false) call failed.", e);
        }
    }

    /**
     * This method differentiates TimeSizeRollingFileAppender from its
     * super class.
     *
     * <p>Before actually logging, this method will check whether it is
     * time to do a rollover. If it is, it will schedule the next
     * rollover time and then rollover.
     * @param event
     */
    protected void subAppend(LoggingEvent event) {
        if ( (fileName != null)
            && ( (CountingQuietWriter) qw).getCount() >= maxFileSize) {
            rollOverForSize();
        }
        long n = System.currentTimeMillis();
        if (n >= nextCheck) {
            now.setTime(n);
            nextCheck = rc.getNextCheckMillis(now);
            try {
                rollOverForTime();
            }
            catch (IOException ioe) {
                LogLog.error("rollOver() failed.", ioe);
            }
        }
        //@CheckItem@ OPT-yanfeng-20030909 remove file exist check while logging for better effencience
        super.subAppend(event);
    }
}

/**
 *  RollingCalendar is a helper class to TimeSizeRollingFileAppender.
 *  Given a periodicity type and the current time, it computes the
 *  start of the next interval.
 */

class RollingCalendar
    extends GregorianCalendar {

    int type = TimeSizeRollingFileAppender.TOP_OF_TROUBLE;

    RollingCalendar() {
        super();
    }

    RollingCalendar(TimeZone tz, Locale locale) {
        super(tz, locale);
    }

    void setType(int type) {
        this.type = type;
    }

    /**
     * @param now
     * @return long
     */
    public long getNextCheckMillis(Date now) {
        return getNextCheckDate(now).getTime();
    }

    /**
     * @param now
     * @return Date
     */
    public Date getNextCheckDate(Date now) {
        this.setTime(now);

        switch (type) {
            case TimeSizeRollingFileAppender.TOP_OF_MINUTE:
                this.set(Calendar.SECOND, 0);
                this.set(Calendar.MILLISECOND, 0);
                this.add(Calendar.MINUTE, 1);
                break;
            case TimeSizeRollingFileAppender.TOP_OF_HOUR:
                this.set(Calendar.MINUTE, 0);
                this.set(Calendar.SECOND, 0);
                this.set(Calendar.MILLISECOND, 0);
                this.add(Calendar.HOUR_OF_DAY, 1);
                break;
            case TimeSizeRollingFileAppender.HALF_DAY:
                this.set(Calendar.MINUTE, 0);
                this.set(Calendar.SECOND, 0);
                this.set(Calendar.MILLISECOND, 0);
                int hour = get(Calendar.HOUR_OF_DAY);
                if (hour < 12) {
                    this.set(Calendar.HOUR_OF_DAY, 12);
                }
                else {
                    this.set(Calendar.HOUR_OF_DAY, 0);
                    this.add(Calendar.DAY_OF_MONTH, 1);
                }
                break;
            case TimeSizeRollingFileAppender.TOP_OF_DAY:
                this.set(Calendar.HOUR_OF_DAY, 0);
                this.set(Calendar.MINUTE, 0);
                this.set(Calendar.SECOND, 0);
                this.set(Calendar.MILLISECOND, 0);
                this.add(Calendar.DATE, 1);
                break;
            case TimeSizeRollingFileAppender.TOP_OF_WEEK:
                this.set(Calendar.DAY_OF_WEEK, getFirstDayOfWeek());
                this.set(Calendar.HOUR_OF_DAY, 0);
                this.set(Calendar.SECOND, 0);
                this.set(Calendar.MILLISECOND, 0);
                this.add(Calendar.WEEK_OF_YEAR, 1);
                break;
            case TimeSizeRollingFileAppender.TOP_OF_MONTH:
                this.set(Calendar.DATE, 1);
                this.set(Calendar.HOUR_OF_DAY, 0);
                this.set(Calendar.SECOND, 0);
                this.set(Calendar.MILLISECOND, 0);
                this.add(Calendar.MONTH, 1);
                break;
            default:
                throw new IllegalStateException("Unknown periodicity type.");
        }
        return getTime();
    }
}