wro4j-core/src/main/java/ro/isdc/wro/util/Transformers.java
public static Transformer<String> extensionTransformer(final String newExtension) {
    return new Transformer<String>() {
      public String transform(final String input) {
        return FilenameUtils.getBaseName(input) + "." + newExtension;
      }
    };
  }
public static Transformer<String> extensionTransformer(final String newExtension) {
    return new Transformer<String>() {
      public String transform(final String input) {
        return FilenameUtils.getBaseName(input) + "." + newExtension;
      }
    };
  }
Creates a {@link Transformer} which replace a original filename extension with a new extension.
@param newExtension extension to use for the returned value.
@return original filename but with the new extension.