LOG4J 在日期的前提下生成多个大小一致的日志（同一天生成多个日志,日志大小可配置）

转载请标明出处！谢谢合作。
![我生成的日志格式为图中所示：每天可以产生多个日志文件，但是日志格式要为图中规定；项目名称+日期+序号（最近的日志序号最小）以此排列；其中scfp-oms.log中的日志为当前正在打印的日志。]

DailyRollingFileAppender 是不支持
log4j.appender.file.MaxFileSize=2KB
log4j.appender.file.MaxBackupIndex=100 的；

因此只能重写其中的实现方法：
代码如下：亲测可用
下面讲述两种日志格式的自定义类：

配置如下：

1、这个自定义类生成的日志格式为：
项目名称+日期+序号.log
package com.amarsoft.are.log;

import java.io.File;
import java.io.IOException;
import java.io.Writer;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.TimeZone;

import org.apache.log4j.FileAppender;
import org.apache.log4j.Layout;
import org.apache.log4j.helpers.CountingQuietWriter;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.helpers.OptionConverter;
import org.apache.log4j.spi.LoggingEvent;

public class MyDailyRollingFileAppender extends FileAppender {
// The code assumes that the following constants are in a increasing
// sequence.
static final int TOP_OF_TROUBLE = -1;
static final int TOP_OF_MINUTE = 0;
static final int TOP_OF_HOUR = 1;
static final int HALF_DAY = 2;
static final int TOP_OF_DAY = 3;
static final int TOP_OF_WEEK = 4;
static final int TOP_OF_MONTH = 5;

/**  * The default maximum file size is 10MB.  */  protected long maxFileSize = 10 * 1024 * 1024;  /**  * There is one backup file by default.  */  protected int maxBackupIndex = 1;  /**  * The date pattern. By default, the pattern is set to "'.'yyyy-MM-dd"  * meaning daily rollover.  */  

// private String datePattern = “’.’yyyy-MM-dd”;
private String datePattern = “’.’yyyy-MM-dd-HH-mm”;

/**  * The log file will be renamed to the value of the scheduledFilename  * variable when the next interval is entered. For example, if the rollover  * period is one hour, the log file will be renamed to the value of  * "scheduledFilename" at the beginning of the next hour.  *   * The precise time when a rollover occurs depends on logging activity.  */  private String scheduledFilename;  /**  * The next time we estimate a rollover should occur.  */  private long nextCheck = System.currentTimeMillis() - 1;  Date now = new Date();  SimpleDateFormat sdf;  RollingCalendar rc = new RollingCalendar();  int checkPeriod = TOP_OF_TROUBLE;  // The gmtTimeZone is used only in computeCheckPeriod() method.  static final TimeZone gmtTimeZone = TimeZone.getTimeZone("GMT");  /**  * The default constructor does nothing.  */  public MyDailyRollingFileAppender() {  }  /**  * Instantiate a <code>MyDailyRollingFileAppender</code> and open the file  * designated by <code>filename</code>. The opened filename will become the  * ouput destination for this appender.  */  public MyDailyRollingFileAppender(Layout layout, String filename,          String datePattern) throws IOException {      super(layout, filename, true);      this.datePattern = datePattern;      activateOptions();  }  /**  * Get the maximum size that the output file is allowed to reach before  * being rolled over to backup files.  *   * @since 1.1  */  public long getMaximumFileSize() {      return maxFileSize;  }  /**  * Set the maximum size that the output file is allowed to reach before  * being rolled over to backup files.  *   * <p>  * This method is equivalent to {@link #setMaxFileSize} except that it is  * required for differentiating the setter taking a <code>long</code>  * argument from the setter taking a <code>String</code> argument by the  * JavaBeans {@link java.beans.Introspector Introspector}.  *   * @see #setMaxFileSize(String)  */  public void setMaximumFileSize(long maxFileSize) {      this.maxFileSize = maxFileSize;  }  /**  * Set the maximum size that the output file is allowed to reach before  * being rolled over to backup files.  *   * <p>  * In configuration files, the <b>MaxFileSize</b> option takes an long  * integer in the range 0 - 2^63. You can specify the value with the  * suffixes "KB", "MB" or "GB" so that the integer is interpreted being  * expressed respectively in kilobytes, megabytes or gigabytes. For example,  * the value "10KB" will be interpreted as 10240.  */  public void setMaxFileSize(String value) {      maxFileSize = OptionConverter.toFileSize(value, maxFileSize + 1);  }  /**  * Returns the value of the <b>MaxBackupIndex</b> option.  */  public int getMaxBackupIndex() {      return maxBackupIndex;  }  /**  * Set the maximum number of backup files to keep around.  *   * <p>  * The <b>MaxBackupIndex</b> option determines how many backup files are  * kept before the oldest is erased. This option takes a positive integer  * value. If set to zero, then there will be no backup files and the log  * file will be truncated when it reaches <code>MaxFileSize</code>.  */  public void setMaxBackupIndex(int maxBackups) {      this.maxBackupIndex = maxBackups;  }  /**  * The <b>DatePattern</b> takes a string in the same format as expected by  * {@link SimpleDateFormat}. This options determines the rollover schedule.  */  public void setDatePattern(String pattern) {      datePattern = pattern;  }  /** Returns the value of the <b>DatePattern</b> option. */  public String getDatePattern() {      return datePattern;  }  public String changeFileName(String fileName){    String fileNameTemp="";    if(fileName.indexOf(".")>-1){        fileNameTemp=fileName.substring(0, fileName.indexOf("."));    }    return fileNameTemp;}public String changeFileName2(String fileName){    String fileNameTemp="";    if(fileName.indexOf(".log")>-1){        fileNameTemp=fileName.substring(0, fileName.indexOf(".log"));    }    return fileNameTemp;}public void activateOptions() {      super.activateOptions();      if (datePattern != null && fileName != null) {          now.setTime(System.currentTimeMillis());          sdf = new SimpleDateFormat(datePattern);          int type = computeCheckPeriod();          printPeriodicity(type);          rc.setType(type);          File file = new File(fileName);        String changeFileName = changeFileName(fileName);        scheduledFilename = changeFileName                  + sdf.format(new Date(file.lastModified()))+".log";      } else {          LogLog.error("Either File or DatePattern options are not set for appender ["                  + name + "].");      }  }  void printPeriodicity(int type) {      switch (type) {      case TOP_OF_MINUTE:          LogLog.debug("Appender [" + name + "] to be rolled every minute.");          break;      case TOP_OF_HOUR:          LogLog.debug("Appender [" + name                  + "] to be rolled on top of every hour.");          break;      case HALF_DAY:          LogLog.debug("Appender [" + name                  + "] to be rolled at midday and midnight.");          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);              // System.out.println("Type = "+i+", r0 = "+r0+", r1 = "+r1);              if (r0 != null && r1 != null && !r0.equals(r1)) {                  return i;              }          }      }      return TOP_OF_TROUBLE; // Deliberately head for trouble...  }  /**  * 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 sizeRollOver() {      File target;      File file;      LogLog.debug("rolling over count="              + ((CountingQuietWriter) qw).getCount());      LogLog.debug("maxBackupIndex=" + maxBackupIndex);      String datedFilename = changeFileName(fileName) + sdf.format(now);      if (maxBackupIndex > 0) {          // Delete the oldest file, to keep Windows happy.          file = new File(datedFilename + '.' + maxBackupIndex+".log");          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(datedFilename + "." + i+".log");              if (file.exists()) {                  target = new File(datedFilename + '.' + (i + 1)+".log");                  LogLog.debug("Renaming file " + file + " to " + target);                  file.renameTo(target);              }          }          // Rename fileName to datedFilename.1          target = new File(datedFilename + "." + 1+".log");          this.closeFile(); // keep windows happy.          file = new File(fileName);          LogLog.debug("Renaming file " + file + " to " + target);          file.renameTo(target);      }else if (maxBackupIndex < 0){//infinite number of files           //find the max backup index          for (int i = 1; i < Integer.MAX_VALUE; i++) {              target = new File(datedFilename + "." + i);              if (! target.exists()) {//Rename fileName to datedFilename.i                  this.closeFile();                  file = new File(fileName);                  file.renameTo(target);                  LogLog.debug("Renaming file " + file + " to " + target);                  break;              }          }      }      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);      }      scheduledFilename = datedFilename;  }  public synchronized void setFile(String fileName, boolean append,          boolean bufferedIO, int bufferSize) throws IOException {      super.setFile(fileName, append, this.bufferedIO, this.bufferSize);      if (append) {          File f = new File(fileName);          ((CountingQuietWriter) qw).setCount(f.length());      }  }  protected void setQWForFiles(Writer writer) {      this.qw = new CountingQuietWriter(writer, errorHandler);  }  /**  * Rollover the current file to a new file.  */  void timeRollOver() throws IOException {      /* Compute filename, but only if datePattern is specified */      if (datePattern == null) {          errorHandler.error("Missing DatePattern option in rollOver().");          return;      }      if(!scheduledFilename.contains(".log")){        scheduledFilename=scheduledFilename+".log";    }    String datedFilename = changeFileName(fileName) + sdf.format(now)+".log";      // 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();        String changeFileName = changeFileName2(scheduledFilename);    File target = new File(changeFileName+".0.log");      if (target.exists()) {          target.delete();      }      File file = new File(fileName);      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.          super.setFile(fileName, false, this.bufferedIO, this.bufferSize);      } catch (IOException e) {          errorHandler.error("setFile(" + fileName + ", false) call failed.");      }      scheduledFilename = datedFilename;  }  /**  * This method differentiates MyDailyRollingFileAppender 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.  * */  protected void subAppend(LoggingEvent event) {      long n = System.currentTimeMillis();      if (n >= nextCheck) {          now.setTime(n);          nextCheck = rc.getNextCheckMillis(now);          try {              timeRollOver();          } catch (IOException ioe) {              LogLog.error("rollOver() failed.", ioe);          }      } else if ((fileName != null)              && ((CountingQuietWriter) qw).getCount() >= maxFileSize) {          sizeRollOver();      }      super.subAppend(event);  }  

}

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

private static final long serialVersionUID = -3221682547248233865L;int type = MyDailyRollingFileAppender.TOP_OF_TROUBLE;  RollingCalendar() {      super();  }  RollingCalendar(TimeZone tz, Locale locale) {      super(tz, locale);  }  void setType(int type) {      this.type = type;  }  public long getNextCheckMillis(Date now) {      return getNextCheckDate(now).getTime();  }  public Date getNextCheckDate(Date now) {      this.setTime(now);      switch (type) {      case MyDailyRollingFileAppender.TOP_OF_MINUTE:          this.set(Calendar.SECOND, 0);          this.set(Calendar.MILLISECOND, 0);          this.add(Calendar.MINUTE, 1);          break;      case MyDailyRollingFileAppender.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 MyDailyRollingFileAppender.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 MyDailyRollingFileAppender.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 MyDailyRollingFileAppender.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 MyDailyRollingFileAppender.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();  }  

}

2、这个自定义类生成的日志格式为：
项目名称.log+日期+序号
package com.amarsoft.are.log;

import java.io.File;
import java.io.IOException;
import java.io.Writer;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.TimeZone;

import org.apache.log4j.FileAppender;
import org.apache.log4j.Layout;
import org.apache.log4j.helpers.CountingQuietWriter;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.helpers.OptionConverter;
import org.apache.log4j.spi.LoggingEvent;

public class MyDailyRollingFileAppender extends FileAppender {
// The code assumes that the following constants are in a increasing
// sequence.
static final int TOP_OF_TROUBLE = -1;
static final int TOP_OF_MINUTE = 0;
static final int TOP_OF_HOUR = 1;
static final int HALF_DAY = 2;
static final int TOP_OF_DAY = 3;
static final int TOP_OF_WEEK = 4;
static final int TOP_OF_MONTH = 5;

/**  * The default maximum file size is 10MB.  */  protected long maxFileSize = 10 * 1024 * 1024;  /**  * There is one backup file by default.  */  protected int maxBackupIndex = 1;  /**  * The date pattern. By default, the pattern is set to "'.'yyyy-MM-dd"  * meaning daily rollover.  */  private String datePattern = "'.'yyyy-MM-dd";  /**  * The log file will be renamed to the value of the scheduledFilename  * variable when the next interval is entered. For example, if the rollover  * period is one hour, the log file will be renamed to the value of  * "scheduledFilename" at the beginning of the next hour.  *   * The precise time when a rollover occurs depends on logging activity.  */  private String scheduledFilename;  /**  * The next time we estimate a rollover should occur.  */  private long nextCheck = System.currentTimeMillis() - 1;  Date now = new Date();  SimpleDateFormat sdf;  RollingCalendar rc = new RollingCalendar();  int checkPeriod = TOP_OF_TROUBLE;  // The gmtTimeZone is used only in computeCheckPeriod() method.  static final TimeZone gmtTimeZone = TimeZone.getTimeZone("GMT");  /**  * The default constructor does nothing.  */  public MyDailyRollingFileAppender() {  }  /**  * Instantiate a <code>MyDailyRollingFileAppender</code> and open the file  * designated by <code>filename</code>. The opened filename will become the  * ouput destination for this appender.  */  public MyDailyRollingFileAppender(Layout layout, String filename,          String datePattern) throws IOException {      super(layout, filename, true);      this.datePattern = datePattern;      activateOptions();  }  /**  * Get the maximum size that the output file is allowed to reach before  * being rolled over to backup files.  *   * @since 1.1  */  public long getMaximumFileSize() {      return maxFileSize;  }  /**  * Set the maximum size that the output file is allowed to reach before  * being rolled over to backup files.  *   * <p>  * This method is equivalent to {@link #setMaxFileSize} except that it is  * required for differentiating the setter taking a <code>long</code>  * argument from the setter taking a <code>String</code> argument by the  * JavaBeans {@link java.beans.Introspector Introspector}.  *   * @see #setMaxFileSize(String)  */  public void setMaximumFileSize(long maxFileSize) {      this.maxFileSize = maxFileSize;  }  /**  * Set the maximum size that the output file is allowed to reach before  * being rolled over to backup files.  *   * <p>  * In configuration files, the <b>MaxFileSize</b> option takes an long  * integer in the range 0 - 2^63. You can specify the value with the  * suffixes "KB", "MB" or "GB" so that the integer is interpreted being  * expressed respectively in kilobytes, megabytes or gigabytes. For example,  * the value "10KB" will be interpreted as 10240.  */  public void setMaxFileSize(String value) {      maxFileSize = OptionConverter.toFileSize(value, maxFileSize + 1);  }  /**  * Returns the value of the <b>MaxBackupIndex</b> option.  */  public int getMaxBackupIndex() {      return maxBackupIndex;  }  /**  * Set the maximum number of backup files to keep around.  *   * <p>  * The <b>MaxBackupIndex</b> option determines how many backup files are  * kept before the oldest is erased. This option takes a positive integer  * value. If set to zero, then there will be no backup files and the log  * file will be truncated when it reaches <code>MaxFileSize</code>.  */  public void setMaxBackupIndex(int maxBackups) {      this.maxBackupIndex = maxBackups;  }  /**  * The <b>DatePattern</b> takes a string in the same format as expected by  * {@link SimpleDateFormat}. This options determines the rollover schedule.  */  public void setDatePattern(String pattern) {      datePattern = pattern;  }  /** Returns the value of the <b>DatePattern</b> option. */  public String getDatePattern() {      return datePattern;  }  public void activateOptions() {      super.activateOptions();      if (datePattern != null && fileName != null) {          now.setTime(System.currentTimeMillis());          sdf = new SimpleDateFormat(datePattern);          int type = computeCheckPeriod();          printPeriodicity(type);          rc.setType(type);          File file = new File(fileName);          scheduledFilename = fileName                  + sdf.format(new Date(file.lastModified()));      } else {          LogLog.error("Either File or DatePattern options are not set for appender ["                  + name + "].");      }  }  void printPeriodicity(int type) {      switch (type) {      case TOP_OF_MINUTE:          LogLog.debug("Appender [" + name + "] to be rolled every minute.");          break;      case TOP_OF_HOUR:          LogLog.debug("Appender [" + name                  + "] to be rolled on top of every hour.");          break;      case HALF_DAY:          LogLog.debug("Appender [" + name                  + "] to be rolled at midday and midnight.");          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);              // System.out.println("Type = "+i+", r0 = "+r0+", r1 = "+r1);              if (r0 != null && r1 != null && !r0.equals(r1)) {                  return i;              }          }      }      return TOP_OF_TROUBLE; // Deliberately head for trouble...  }  /**  * 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 sizeRollOver() {      File target;      File file;      LogLog.debug("rolling over count="              + ((CountingQuietWriter) qw).getCount());      LogLog.debug("maxBackupIndex=" + maxBackupIndex);      String datedFilename = fileName + sdf.format(now);      if (maxBackupIndex > 0) {          // Delete the oldest file, to keep Windows happy.          file = new File(datedFilename + '.' + 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(datedFilename + "." + i);              if (file.exists()) {                  target = new File(datedFilename + '.' + (i + 1));                  LogLog.debug("Renaming file " + file + " to " + target);                  file.renameTo(target);              }          }          // Rename fileName to datedFilename.1          target = new File(datedFilename + "." + 1);          this.closeFile(); // keep windows happy.          file = new File(fileName);          LogLog.debug("Renaming file " + file + " to " + target);          file.renameTo(target);      }else if (maxBackupIndex < 0){//infinite number of files           //find the max backup index          for (int i = 1; i < Integer.MAX_VALUE; i++) {              target = new File(datedFilename + "." + i);              if (! target.exists()) {//Rename fileName to datedFilename.i                  this.closeFile();                  file = new File(fileName);                  file.renameTo(target);                  LogLog.debug("Renaming file " + file + " to " + target);                  break;              }          }      }      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);      }      scheduledFilename = datedFilename;  }  public synchronized void setFile(String fileName, boolean append,          boolean bufferedIO, int bufferSize) throws IOException {      super.setFile(fileName, append, this.bufferedIO, this.bufferSize);      if (append) {          File f = new File(fileName);          ((CountingQuietWriter) qw).setCount(f.length());      }  }  protected void setQWForFiles(Writer writer) {      this.qw = new CountingQuietWriter(writer, errorHandler);  }  /**  * Rollover the current file to a new file.  */  void timeRollOver() throws IOException {      /* 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);      // 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);      if (target.exists()) {          target.delete();      }      File file = new File(fileName);      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.          super.setFile(fileName, false, this.bufferedIO, this.bufferSize);      } catch (IOException e) {          errorHandler.error("setFile(" + fileName + ", false) call failed.");      }      scheduledFilename = datedFilename;  }  /**  * This method differentiates MyDailyRollingFileAppender 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.  * */  protected void subAppend(LoggingEvent event) {      long n = System.currentTimeMillis();      if (n >= nextCheck) {          now.setTime(n);          nextCheck = rc.getNextCheckMillis(now);          try {              timeRollOver();          } catch (IOException ioe) {              LogLog.error("rollOver() failed.", ioe);          }      } else if ((fileName != null)              && ((CountingQuietWriter) qw).getCount() >= maxFileSize) {          sizeRollOver();      }      super.subAppend(event);  }  

}

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

private static final long serialVersionUID = -3221682547248233865L;int type = MyDailyRollingFileAppender.TOP_OF_TROUBLE;  RollingCalendar() {      super();  }  RollingCalendar(TimeZone tz, Locale locale) {      super(tz, locale);  }  void setType(int type) {      this.type = type;  }  public long getNextCheckMillis(Date now) {      return getNextCheckDate(now).getTime();  }  public Date getNextCheckDate(Date now) {      this.setTime(now);      switch (type) {      case MyDailyRollingFileAppender.TOP_OF_MINUTE:          this.set(Calendar.SECOND, 0);          this.set(Calendar.MILLISECOND, 0);          this.add(Calendar.MINUTE, 1);          break;      case MyDailyRollingFileAppender.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 MyDailyRollingFileAppender.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 MyDailyRollingFileAppender.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 MyDailyRollingFileAppender.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 MyDailyRollingFileAppender.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();  }  

}