properties.java

this gcc-g++-3.3.1.tar.gz is a source file of gcc, you can learn more about gcc through this codes f

                                           element.length());
                  }
                else
                  {
                    c = line.charAt(pos++);
                    switch (c)
                      {
                      case 'n':
                        element.append('\n');
                        break;
                      case 't':
                        element.append('\t');
                        break;
                      case 'r':
                        element.append('\r');
                        break;
                      case 'u':
                        if (pos + 4 <= line.length())
                          {
                            char uni = (char) Integer.parseInt
                              (line.substring(pos, pos + 4), 16);
                            element.append(uni);
                            pos += 4;
                          }        // else throw exception?
                        break;
                      default:
                        element.append(c);
                        break;
                      }
                  }
              }
            else
              element.append(c);
          }
        put(key.toString(), element.toString());
      }
  }

  /**
   * Calls <code>store(OutputStream out, String header)</code> and
   * ignores the IOException that may be thrown.
   *
   * @param out the stream to write to
   * @param header a description of the property list
   * @throws ClassCastException if this property contains any key or
   *         value that are not strings
   * @deprecated use {@link #store(OutputStream, String)} instead
   */
  public void save(OutputStream out, String header)
  {
    try
      {
        store(out, header);
      }
    catch (IOException ex)
      {
      }
  }

  /**
   * Writes the key/value pairs to the given output stream, in a format
   * suitable for <code>load</code>.<br>
   *
   * If header is not null, this method writes a comment containing
   * the header as first line to the stream.  The next line (or first
   * line if header is null) contains a comment with the current date.
   * Afterwards the key/value pairs are written to the stream in the
   * following format.<br>
   *
   * Each line has the form <code>key = value</code>.  Newlines,
   * Returns and tabs are written as <code>\n,\t,\r</code> resp.
   * The characters <code>\, !, #, =</code> and <code>:</code> are
   * preceeded by a backslash.  Spaces are preceded with a backslash,
   * if and only if they are at the beginning of the key.  Characters
   * that are not in the ascii range 33 to 127 are written in the
   * <code>\</code><code>u</code>xxxx Form.<br>
   *
   * Following the listing, the output stream is flushed but left open.
   *
   * @param out the output stream
   * @param header the header written in the first line, may be null
   * @throws ClassCastException if this property contains any key or
   *         value that isn't a string
   * @throws IOException if writing to the stream fails
   * @throws NullPointerException if out is null
   * @since 1.2
   */
  public void store(OutputStream out, String header) throws IOException
  {
    // The spec says that the file must be encoded using ISO-8859-1.
    PrintWriter writer
      = new PrintWriter(new OutputStreamWriter(out, "ISO-8859-1"));
    if (header != null)
      writer.println("#" + header);
    writer.println ("#" + Calendar.getInstance ().getTime ());
    
    Iterator iter = entrySet ().iterator ();
    int i = size ();
    StringBuffer s = new StringBuffer (); // Reuse the same buffer.
    while (--i >= 0)
      {
        Map.Entry entry = (Map.Entry) iter.next ();
        formatForOutput ((String) entry.getKey (), s, true);
        s.append ('=');
        formatForOutput ((String) entry.getValue (), s, false);
        writer.println (s);
      }

    writer.flush ();
  }

  /**
   * Gets the property with the specified key in this property list.
   * If the key is not found, the default property list is searched.
   * If the property is not found in the default, null is returned.
   *
   * @param key The key for this property
   * @return the value for the given key, or null if not found
   * @throws ClassCastException if this property contains any key or
   *         value that isn't a string
   * @see #defaults
   * @see #setProperty(String, String)
   * @see #getProperty(String, String)
   */
  public String getProperty(String key)
  {
    return getProperty(key, null);
  }

  /**
   * Gets the property with the specified key in this property list.  If
   * the key is not found, the default property list is searched.  If the
   * property is not found in the default, the specified defaultValue is
   * returned.
   *
   * @param key The key for this property
   * @param defaultValue A default value
   * @return The value for the given key
   * @throws ClassCastException if this property contains any key or
   *         value that isn't a string
   * @see #defaults
   * @see #setProperty(String, String)
   */
  public String getProperty(String key, String defaultValue)
  {
    Properties prop = this;
    // Eliminate tail recursion.
    do
      {
        String value = (String) prop.get(key);
        if (value != null)
          return value;
        prop = prop.defaults;
      }
    while (prop != null);
    return defaultValue;
  }

  /**
   * Returns an enumeration of all keys in this property list, including
   * the keys in the default property list.
   *
   * @return an Enumeration of all defined keys
   */
  public Enumeration propertyNames()
  {
    // We make a new Set that holds all the keys, then return an enumeration
    // for that. This prevents modifications from ruining the enumeration,
    // as well as ignoring duplicates.
    Properties prop = this;
    Set s = new HashSet();
    // Eliminate tail recursion.
    do
      {
        s.addAll(prop.keySet());
        prop = prop.defaults;
      }
    while (prop != null);
    return Collections.enumeration(s);
  }

  /**
   * Prints the key/value pairs to the given print stream.  This is 
   * mainly useful for debugging purposes.
   *
   * @param out the print stream, where the key/value pairs are written to
   * @throws ClassCastException if this property contains a key or a
   *         value that isn't a string
   * @see #list(PrintWriter)
   */
  public void list(PrintStream out)
  {
    PrintWriter writer = new PrintWriter (out);
    list (writer);
  }

  /**
   * Prints the key/value pairs to the given print writer.  This is
   * mainly useful for debugging purposes.
   *
   * @param out the print writer where the key/value pairs are written to
   * @throws ClassCastException if this property contains a key or a
   *         value that isn't a string
   * @see #list(PrintStream)
   * @since 1.1
   */
  public void list(PrintWriter out)
  {
    out.println ("-- listing properties --");

    Iterator iter = entrySet ().iterator ();
    int i = size ();
    while (--i >= 0)
      {
        Map.Entry entry = (Map.Entry) iter.next ();
        out.print ((String) entry.getKey () + "=");

        // JDK 1.3/1.4 restrict the printed value, but not the key,
        // to 40 characters, including the truncating ellipsis.
        String s = (String ) entry.getValue ();
        if (s != null && s.length () > 40)
          out.println (s.substring (0, 37) + "...");
        else
          out.println (s);
      }
    out.flush ();
  }

  /**
   * Formats a key or value for output in a properties file.
   * See store for a description of the format.
   *
   * @param str the string to format
   * @param buffer the buffer to add it to
   * @param key true if all ' ' must be escaped for the key, false if only
   *        leading spaces must be escaped for the value
   * @see #store(OutputStream, String)
   */
  private void formatForOutput(String str, StringBuffer buffer, boolean key)
  {
    if (key)
      {
        buffer.setLength(0);
        buffer.ensureCapacity(str.length());
      }
    else
      buffer.ensureCapacity(buffer.length() + str.length());
    boolean head = true;
    int size = str.length();
    for (int i = 0; i < size; i++)
      {
        char c = str.charAt(i);
        switch (c)
          {
          case '\n':
            buffer.append("\\n");
            break;
          case '\r':
            buffer.append("\\r");
            break;
          case '\t':
            buffer.append("\\t");
            break;
          case ' ':
            buffer.append(head ? "\\ " : " ");
            break;
          case '\\':
          case '!':
          case '#':
          case '=':
          case ':':
            buffer.append('\\').append(c);
            break;
          default:
            if (c < ' ' || c > '~')
              {
                String hex = Integer.toHexString(c);
                buffer.append("\\u0000".substring(0, 6 - hex.length()));
                buffer.append(hex);
              }
            else
              buffer.append(c);
          }
        if (c != ' ')
          head = key;
      }
  }
} // class Properties