code: public static <T> Filter<T> filter(final Path.Filter filter, final Content.Type<T> contentType) {
  		return new Filter<T>() {
  			@Override
  			public boolean matches(Path.ID id, Content.Type<T> ct) {
  				return ct == contentType && filter.matches(id);
  			}
  			@Override
  			public boolean matchesSubpath(Path.ID id) {
  				return filter.matchesSubpath(id);
  			}
  			@Override
  			public String toString() {
  				return filter.toString();
  			}
  		};
  	}
docs: Construct a content filter from a path filter and a content type.
  
  @param filter --- path filter
  @param contentType
  @return