code: public static CharSource asCharSource(final Class<?> contextClass, final String resourceName, final Charset charset) {
  		return new CharSource() {
  			@Override public Reader openStream() throws IOException {
  				return asReader(checkNotNull(contextClass).getResourceAsStream(checkNotEmpty(resourceName)), checkNotNull(charset));
  			}
  		};
  	}
docs: Returns the given source as a {@link CharSource} with given charset
  
  @param contextClass
  @param resourceName
  @param charset
  @return