code: @Override
  	public String setForceError(String forceError) {
  		String result = ""; //$NON-NLS-1$
  		// Listen for FORCE_ERROR option.  FORCED_ERROR is a transient options, so we
  		// can only learn that it is set in optionsUpdated.
  		if (getOptions().isDevelopmentMode()) {
  			ForcedErrorResponse resp;
  			try {
  				resp = newForcedErrorResponse(forceError);
  				result = MessageFormat.format(Messages.CommandProvider_27, new Object[]{resp.toString()});
  				forcedErrorResponse = resp;
  			} catch (Exception e) {
  				result = MessageFormat.format(Messages.CommandProvider_28, new Object[]{forceError});
  			}
  		} else {
  			result = Messages.CommandProvider_29;
  		}
  		return result;
  	}
docs: /* (non-Javadoc)
  @see com.ibm.jaggr.core.IAggregator#setForceError(java.lang.String)