code: public static <T> Filter<T> eq(final T object) {
          return new NonMutatingFilter<T>() {
              @Override
              protected boolean accepts(T item) {
                  return object.equals(item);
              }
          };
      }
docs: Gets a filter that returns the original value if
  <code>object.equals(value)</code>, otherwise returns <code>null</code>.
  
  @param object the object to compare.
  @param <T> the type.
  @return the filter.