@Override
    public String buildContext() {
        final String metadata = ((Collection<?>) getSource())
                .stream()
                .map(s -> ((MetaDataDO) s).getAppName())
                .collect(Collectors.joining(","));
        return String.format("the meta data [%s] is %s", metadata, StringUtils.lowerCase(getType().getType().toString()));
    }
@Test
    public void batchMetaDataChangedContextTest() {
        BatchMetaDataChangedEvent batchMetaDataChangedEvent =
                new BatchMetaDataChangedEvent(Arrays.asList(one, two), null, EventTypeEnum.META_DATA_UPDATE, "test-operator");

        String context = String.format("the meta data [%s] is %s",
                "testAppNameOne,testAppNameTwo", StringUtils.lowerCase(EventTypeEnum.META_DATA_UPDATE.getType().toString()));

        assertEquals(context, batchMetaDataChangedEvent.buildContext());
    }