@Nonnull
  public PreprocessorContext setExtensions(@Nonnull @MustNotContainNull final List<String> extensions) {
    this.extensions = new HashSet<>(assertDoesntContainNull(extensions));
    return this;
  }
@ Nonnull public PreprocessorContext setExtensions ( @ Nonnull @ MustNotContainNull final List < String > extensions ) { this . extensions = new HashSet < > ( assertDoesntContainNull ( extensions ) ) ; return this ; }
Set file extensions of files to be preprocessed, it is a comma separated list

@param extensions comma separated extensions list of file extensions to be preprocessed, must not be null
@return this preprocessor context