Defining new type convertors

Depending on the options specified in the configuration file, the BMProcessor may automatically cast the variable it uses. This casting may be enabled on arguments used:

• in beans' creations,
• in method calls,
• in properties initialization, or
• in fields initialization

The cast is performed by a method which is able, given a certain type of data, to convert it into another type. For example, the code below handle the conversion of a string into several different target classes:

  /**
   * Default convertor for an object of class String
   *
   * @param str    the string to convert
   * @param target the desired class
   *
   * @return a new object of the desired class
   *
   **/
  public Object convert(String str, Class target)
    throws java.lang.ClassCastException,
    java.lang.NumberFormatException {
    if ((str == null) 
        || target.isInstance(str)
        || target.isAssignableFrom(str.getClass()))
      return str;
    if (target == boolean.class) {
      return new Boolean(str);
    }
    if (target == char.class) {
      if (str.length() != 1) {
        throw new java.lang.ClassCastException("incompatible value for data");
      }
      return new Character(str.charAt(0));
    }
    if (target == byte.class) {
      if ("".equals(str)) str = "0";
      return new Byte(str);
    }
    
    ... similar code to convert the string into 'short', 'int', ...
    
    if (target == java.awt.Color.class) {
      Integer c = Integer.decode(str);
      return new java.awt.Color(c.intValue());
    }
    throw new java.lang.ClassCastException("impossible conversion from "
                                           + "an object of class "
                                           + str.getClass().getName()
                                           + " to an object of class "
                                           + target.getName() +".");
  }

The classes where type convertors are defined must be registered in the configuration file in the following way:

<register type="typeConvertor"
          method="convert"
          class="fr.inria.ketuk.TypeConvertor"/>