private boolean isIndexInitialised() {
        return indexInitialisedLatch.getCount() == 0;
    }
Creation of the content index (or re-indexing it) is triggered by a user doing a content
search. This ensures that only UI nodes create the index.
The index is also updated on a doc basis by this class handling {@link EntityEvent}s however
they will be ignored if the index is not initialised.
There is also a managed job that will trigger a full re-index
stroom-index/stroom-index-lucene980/src/main/java/stroom/contentindex/LuceneContentIndex.java