code: protected void setProps(Properties props) {
  		this.props = props;
  		// Update the shadow map
  		Map<String, String> map = new HashMap<String, String>();
  		for (String name : props.stringPropertyNames()) {
  			map.put(name, (String)props.getProperty(name));
  		}
  		shadowMap = Collections.unmodifiableMap(map);
  	}
docs: Sets the properties object for the current options and updates
  the shadow map that is returned to callers of {@link #getOptionsMap()}.
  
  @param props The new properties.