* Parses an XML-file specifying the 'annotations'.

* The XML must have the structure:

* <pre>

* &lt;args&gt;

*     &lt;option field="" method="" name="" usage="" metavar="" handler=""/&gt;

*     &lt;argument field="" method="" usage="" metavar="" handler=""/&gt;

* &lt;/args&gt;

* </pre>

* Exactly one of the attributes 'field' or 'method' must be set.

* The 'handler' value specifies a full qualified class name.

*

* <h3>Example</h3>

* <pre>

* &lt;args&gt;

*     &lt;option field="recursive" name="-r" usage="recursively run something"/&gt;

*     &lt;option field="out" name="-o" usage="output to this file" metavar="OUTPUT"/&gt;

*     &lt;option method="setStr(String)" name="-str"/&gt;

*     &lt;option field="data" name="-custom" handler="org.kohsuke.args4j.spi.BooleanOptionHandler" usage="boolean value for checking the custom handler"/&gt;

*     &lt;argument field="arguments"/&gt;

* &lt;args&gt;

* </pre>

*

* @author Jan Materne

*/

    public void parse(URL xml, CmdLineParser parser, Object bean) {

        parse(new InputSource(xml.toExternalForm()),parser,bean);

    }

  public void parse(InputSource xml, CmdLineParser parser, Object bean) {

    try {

      Config config = Config.parse(xml);

      for(ConfigElement ce : config.options) {

        Option option = new OptionImpl(ce);

                parser.addOption(Setters.create(parser, findMethodOrField(bean, ce.field, ce.method),bean), option);

      }

      for (ConfigElement ce : config.arguments) {

        Argument argument = new ArgumentImpl(ce);

        parser.addArgument(Setters.create(parser, findMethodOrField(bean, ce.field, ce.method),bean), argument);

      }

    } catch (Exception e) {

      throw new RuntimeException(Messages.METADATA_ERROR.format(), e);

    }

  }

  /**

   * Finds a {@link java.lang.reflect.Method} or {@link java.lang.reflect.Method} in the bean

   * instance with the requested name.

   * @param bean    bean instance

   * @param field   name of the field (field XOR method must be specified)

   * @param method  name of the method (field XOR method must be specified)

   * @return the reflection reference

   * @throws SecurityException

   * @throws NoSuchFieldException

   * @throws NoSuchMethodException

   * @throws ClassNotFoundException

   */

  private AccessibleObject findMethodOrField(Object bean, String field, String method) throws SecurityException, NoSuchFieldException, NoSuchMethodException, ClassNotFoundException {

    AccessibleObject rv;

    if (field != null) {

      rv = bean.getClass().getDeclaredField(field);

    } else {

      String methodName = method.substring(0, method.indexOf("("));

      String[] params = method.substring(method.indexOf("(")+1, method.indexOf(")")).split(",");

      Class[] paramTypes = new Class[params.length];

      for(int i=0; i<params.length; i++) {

        String className = params[i];

        if (className.indexOf('.') < 0) {

          className = "java.lang." + className;

        }

        paramTypes[i] = Class.forName(className);

      }

      rv = bean.getClass().getMethod(methodName, paramTypes);

    }

    return rv;

  }

}