code: public static Boolean getOptionalBooleanParameter(UimaContext context,
        String parameter)
        throws ResourceInitializationException {
      Object value = getOptionalParameter(context, parameter);
  
      if (value instanceof Boolean) {
        return (Boolean) value;
      }
      else if (value == null) {
        return null;
      }
      else {
        throw new ResourceInitializationException(
                ExceptionMessages.MESSAGE_CATALOG,
                ExceptionMessages.WRONG_PARAMETER_TYPE,
                new Object[] {parameter, "Boolean"});
      }
    }
docs: Retrieves an optional parameter from the given context.
  
  @param context
  @param parameter
  @return the parameter or null if not set
  
  @throws ResourceInitializationException