filehandler.java

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  /* FIXME: Javadoc missing. */
  public FileHandler(String pattern, boolean append)
    throws IOException, SecurityException
  {
    this(pattern,
	 /* limit */ 0,
	 /* count */ 1,
	 append);
  }


  /* FIXME: Javadoc missing. */
  public FileHandler(String pattern, int limit, int count)
    throws IOException, SecurityException
  {
    this(pattern, limit, count, 
	 LogManager.getBooleanProperty(
	   "java.util.logging.FileHandler.append",
	   /* default */ false));
  }


  /**
   * Constructs a <code>FileHandler</code> given the pattern for the
   * location and name of the produced log files, the size limit, the
   * number of log files thorough which the handler will rotate, and
   * the <code>append</code> property.  All other property values are
   * taken from the current {@link LogManager LogManager}
   * configuration.
   *
   * @param pattern The pattern for the location and name of the
   *        produced log files.  See the section on <a
   *        href="#filePatterns">file name patterns</a> for details.
   *        If <code>pattern</code> is <code>null</code>, the value is
   *        taken from the {@link LogManager LogManager} configuration
   *        property
   *        <code>java.util.logging.FileHandler.pattern</code>.
   *        However, this is a pecularity of the GNU implementation,
   *        and Sun's API specification does not mention what behavior
   *        is to be expected for <code>null</code>. Therefore,
   *        applications should not rely on this feature.
   *
   * @param limit specifies the number of bytes a log file is
   *        approximately allowed to reach before it is closed and the
   *        handler switches to the next file in the rotating set.  A
   *        value of zero means that files can grow without limit.
   *
   * @param count specifies the number of log files through which this
   *        handler cycles.
   *
   * @param append specifies whether the handler will append log
   *        records to existing files (<code>true</code>), or whether the
   *        handler will clear log files upon switching to them
   *        (<code>false</code>).
   *
   * @throws java.io.IOException FIXME: The Sun Javadoc says: "if
   *         there are IO problems opening the files."  This conflicts
   *         with the general principle that configuration errors do
   *         not prohibit construction. Needs review.
   *
   * @throws SecurityException if a security manager exists and
   *         the caller is not granted the permission to control
   *         the logging infrastructure.
   *         <p>FIXME: This seems in contrast to all other handler
   *         constructors -- verify this by running tests against
   *         the Sun reference implementation.
   */
  public FileHandler(String pattern,
		     int limit,
		     int count,
		     boolean append)
    throws IOException, SecurityException
  {
    super(createFileStream(pattern, limit, count, append,
			   /* generation */ 0),
	  "java.util.logging.FileHandler",
	  /* default level */ Level.ALL,
	  /* formatter */ null,
	  /* default formatter */ XMLFormatter.class);

    if ((limit <0) || (count < 1))
      throw new IllegalArgumentException();

    this.pattern = pattern;
    this.limit = limit;
    this.count = count;
    this.append = append;
  }


  /* FIXME: Javadoc missing. */
  private static java.io.OutputStream createFileStream(String pattern,
						       int limit,
						       int count,
						       boolean append,
						       int generation)
  {
    String  path;
    int     unique = 0;

    /* Throws a SecurityException if the caller does not have
     * LoggingPermission("control").
     */
    LogManager.getLogManager().checkAccess();

    /* Default value from the java.util.logging.FileHandler.pattern
     * LogManager configuration property.
     */
    if (pattern == null)
      pattern = LogManager.getLogManager().getProperty(
                              "java.util.logging.FileHandler.pattern");
    if (pattern == null)
      pattern = "%h/java%u.log";

    do
    {
      path = replaceFileNameEscapes(pattern, generation, unique, count);

      try
      {
	File file = new File(path);
	if (file.createNewFile())
	  return new FileOutputStream(path, append);
      }
      catch (Exception ex)
      {
	ex.printStackTrace();	
      }

      unique = unique + 1;
      if (pattern.indexOf("%u") < 0)
        pattern = pattern + ".%u";
    }
    while (true);
  }


  /**
   * Replaces the substrings <code>"/"</code> by the value of the
   * system property <code>"file.separator"</code>, <code>"%t"</code>
   * by the value of the system property
   * <code>"java.io.tmpdir"</code>, <code>"%h"</code> by the value of
   * the system property <code>"user.home"</code>, <code>"%g"</code>
   * by the value of <code>generation</code>, <code>"%u"</code> by the
   * value of <code>uniqueNumber</code>, and <code>"%%"</code> by a
   * single percent character.  If <code>pattern<code> does
   * <em>not</em> contain the sequence <code>"%g"</code>,
   * the value of <code>generation</code> will be appended to
   * the result.
   *
   * @throws NullPointerException if one of the system properties
   *         <code>"file.separator"</code>,
   *         <code>"java.io.tmpdir"</code>, or
   *         <code>"user.home"</code> has no value and the
   *         corresponding escape sequence appears in
   *         <code>pattern</code>.
   */
  private static String replaceFileNameEscapes(String pattern,
					       int generation,
					       int uniqueNumber,
					       int count)
  {
    StringBuffer buf = new StringBuffer(pattern);
    String       replaceWith;
    boolean      foundGeneration = false;

    int pos = 0;
    do
    {
      // Uncomment the next line for finding bugs.
      // System.out.println(buf.substring(0,pos) + '|' + buf.substring(pos));
      
      if (buf.charAt(pos) == '/')
      {
	/* The same value is also provided by java.io.File.separator. */
	replaceWith = System.getProperty("file.separator");
	buf.replace(pos, pos + 1, replaceWith);
	pos = pos + replaceWith.length() - 1;
	continue;
      }

      if (buf.charAt(pos) == '%')
      {
        switch (buf.charAt(pos + 1))
	{
	case 't':
	  replaceWith = System.getProperty("java.io.tmpdir");
	  break;

	case 'h':
	  replaceWith = System.getProperty("user.home");
	  break;

	case 'g':
	  replaceWith = Integer.toString(generation);
	  foundGeneration = true;
	  break;

	case 'u':
	  replaceWith = Integer.toString(uniqueNumber);
	  break;

	case '%':
	  replaceWith = "%";
	  break;

	default:
	  replaceWith = "??";
	  break; // FIXME: Throw exception?
	}

	buf.replace(pos, pos + 2, replaceWith);
	pos = pos + replaceWith.length() - 1;
	continue;
      }
    }
    while (++pos < buf.length() - 1);

    if (!foundGeneration && (count > 1))
    {
      buf.append('.');
      buf.append(generation);
    }

    return buf.toString();
  }


  /* FIXME: Javadoc missing, implementation incomplete. */
  public void publish(LogRecord record)
  {
    super.publish(record);

    /* FIXME: Decide when to switch over. How do we get to
     * the number of bytes published so far? Two possibilities:
     * 1. File.length, 2. have metering wrapper around
     * output stream counting the number of written bytes.
     */
  
    /* FIXME: Switch over if needed! This implementation always
     * writes into a single file, i.e. behaves as if limit
     * always was zero. So, the implementation is somewhat
     * functional but incomplete.
     */
  }
}