Java tutorial
// ======================================================================== // $Id: RolloverFileOutputStream.java,v 1.14 2005/08/13 00:01:28 gregwilkins Exp $ // Copyright 1997-2004 Mort Bay Consulting Pty. Ltd. // ------------------------------------------------------------------------ // Licensed 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.openqa.jetty.util; import org.apache.commons.logging.Log; import org.openqa.jetty.log.LogFactory; import java.io.File; import java.io.FileOutputStream; import java.io.FilterOutputStream; import java.io.IOException; import java.io.OutputStream; import java.lang.ref.WeakReference; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; import java.util.ListIterator; import java.util.StringTokenizer; /* ------------------------------------------------------------ */ /** A File OutputStream that rolls overs. * If the passed filename contains the string "yyyy_mm_dd" on daily intervals. * @version $Id: RolloverFileOutputStream.java,v 1.14 2005/08/13 00:01:28 gregwilkins Exp $ * @author Greg Wilkins (gregw) */ public class RolloverFileOutputStream extends FilterOutputStream { static Log log = LogFactory.getLog(RolloverFileOutputStream.class); static Rollover __rollover; final static String YYYY_MM_DD = "yyyy_mm_dd"; final static ArrayList __rollovers = new ArrayList(); private SimpleDateFormat _fileBackupFormat = new SimpleDateFormat( System.getProperty("ROLLOVERFILE_BACKUP_FORMAT", "HHmmssSSS")); private SimpleDateFormat _fileDateFormat = new SimpleDateFormat( System.getProperty("ROLLOVERFILE_DATE_FORMAT", "yyyy_MM_dd")); private String _filename; private File _file; private boolean _append; private int _retainDays; private WeakReference _ref; /* ------------------------------------------------------------ */ public RolloverFileOutputStream(String filename) throws IOException { this(filename, true, Integer.getInteger("ROLLOVERFILE_RETAIN_DAYS", 31).intValue()); } /* ------------------------------------------------------------ */ public RolloverFileOutputStream(String filename, boolean append) throws IOException { this(filename, append, Integer.getInteger("ROLLOVERFILE_RETAIN_DAYS", 31).intValue()); } /* ------------------------------------------------------------ */ public RolloverFileOutputStream(String filename, boolean append, int retainDays) throws IOException { super(null); if (filename != null) { filename = filename.trim(); if (filename.length() == 0) filename = null; } if (filename == null) throw new IllegalArgumentException("Invalid filename"); _filename = filename; _append = append; _retainDays = retainDays; _ref = new WeakReference(this); setFile(); synchronized (__rollovers) { if (__rollover == null) { __rollover = new Rollover(); __rollover.start(); } __rollovers.add(_ref); } } /* ------------------------------------------------------------ */ public String getFilename() { return _filename; } /* ------------------------------------------------------------ */ public String getDatedFilename() { if (_file == null) return null; return _file.toString(); } /* ------------------------------------------------------------ */ public int getRetainDays() { return _retainDays; } /* ------------------------------------------------------------ */ private synchronized void setFile() throws IOException { // Check directory File file = new File(_filename); _filename = file.getCanonicalPath(); file = new File(_filename); File dir = new File(file.getParent()); if (!dir.isDirectory() || !dir.canWrite()) throw new IOException("Cannot write log directory " + dir); Date now = new Date(); // Is this a rollover file? String filename = file.getName(); int i = filename.toLowerCase().indexOf(YYYY_MM_DD); if (i >= 0) { file = new File(dir, filename.substring(0, i) + _fileDateFormat.format(now) + filename.substring(i + YYYY_MM_DD.length())); } if (file.exists() && !file.canWrite()) throw new IOException("Cannot write log file " + file); // Do we need to change the output stream? if (out == null || !file.equals(_file)) { // Yep _file = file; if (!_append && file.exists()) file.renameTo(new File(file.toString() + "." + _fileBackupFormat.format(now))); OutputStream oldOut = out; out = new FileOutputStream(file.toString(), _append); if (oldOut != null) oldOut.close(); if (log.isDebugEnabled()) log.debug("Opened " + _file); } } /* ------------------------------------------------------------ */ private void removeOldFiles() { if (_retainDays > 0) { Calendar retainDate = Calendar.getInstance(); retainDate.add(Calendar.DATE, -_retainDays); int borderYear = retainDate.get(java.util.Calendar.YEAR); int borderMonth = retainDate.get(java.util.Calendar.MONTH) + 1; int borderDay = retainDate.get(java.util.Calendar.DAY_OF_MONTH); File file = new File(_filename); File dir = new File(file.getParent()); String fn = file.getName(); int s = fn.toLowerCase().indexOf(YYYY_MM_DD); if (s < 0) return; String prefix = fn.substring(0, s); String suffix = fn.substring(s + YYYY_MM_DD.length()); String[] logList = dir.list(); for (int i = 0; i < logList.length; i++) { fn = logList[i]; if (fn.startsWith(prefix) && fn.indexOf(suffix, prefix.length()) >= 0) { try { StringTokenizer st = new StringTokenizer( fn.substring(prefix.length(), prefix.length() + YYYY_MM_DD.length()), "_."); int nYear = Integer.parseInt(st.nextToken()); int nMonth = Integer.parseInt(st.nextToken()); int nDay = Integer.parseInt(st.nextToken()); if (nYear < borderYear || (nYear == borderYear && nMonth < borderMonth) || (nYear == borderYear && nMonth == borderMonth && nDay <= borderDay)) { log.info("Log age " + fn); new File(dir, fn).delete(); } } catch (Exception e) { if (log.isDebugEnabled()) e.printStackTrace(); } } } } } /* ------------------------------------------------------------ */ public void write(byte[] buf) throws IOException { out.write(buf); } /* ------------------------------------------------------------ */ public void write(byte[] buf, int off, int len) throws IOException { out.write(buf, off, len); } /* ------------------------------------------------------------ */ /** */ public void close() throws IOException { synchronized (__rollovers) { __rollovers.remove(_ref); _ref = null; try { super.close(); } finally { out = null; _file = null; } // this will kill the thread when the last stream is removed. if (__rollovers.size() == 0) { __rollover.timeToStop(); __rollover.interrupt(); __rollover = null; } } } /* ------------------------------------------------------------ */ /* ------------------------------------------------------------ */ /* ------------------------------------------------------------ */ private class Rollover extends Thread // Thread safety reviewed { private volatile boolean timeToStop = false; Rollover() { setName("Rollover"); setDaemon(true); } synchronized void timeToStop() { timeToStop = true; } public void run() { while (!timeToStop) { try { // Sleep until midnight Calendar now = Calendar.getInstance(); GregorianCalendar midnight = new GregorianCalendar(now.get(Calendar.YEAR), now.get(Calendar.MONTH), now.get(Calendar.DAY_OF_MONTH), 23, 0); midnight.add(Calendar.HOUR, 1); long sleeptime = midnight.getTime().getTime() - now.getTime().getTime(); if (log.isDebugEnabled()) log.debug("Rollover sleep until " + midnight.getTime()); Thread.sleep(sleeptime); } catch (InterruptedException e) { if (!timeToStop) e.printStackTrace(); } synchronized (__rollovers) { ListIterator iter = __rollovers.listIterator(); while (iter.hasNext()) { WeakReference ref = (WeakReference) iter.next(); RolloverFileOutputStream rfos = (RolloverFileOutputStream) ref.get(); if (rfos == null) iter.remove(); else { try { rfos.setFile(); rfos.removeOldFiles(); } catch (IOException e) { if (!timeToStop) e.printStackTrace(); } } } } } } } }