@Override
    public boolean isManagedIndex(String index) {
        return !isNullOrEmpty(index) && !isWriteIndexAlias(index) && indexPattern.matcher(index).matches();
    }
@Test
    public void identifiesIndicesWithPlusAsBeingManaged() {
        final IndexSetConfig configWithPlus = config.toBuilder().indexPrefix("some+index").build();
        final String indexName = configWithPlus.indexPrefix() + "_0";

        final MongoIndexSet mongoIndexSet = createIndexSet(configWithPlus);

        assertThat(mongoIndexSet.isManagedIndex(indexName)).isTrue();
    }