@Override
    public Source openSource(final long streamId) throws DataException {
        return openSource(streamId, false);
    }
<p>
Open a existing stream source.
</p>

@param streamId the id of the stream to open.
@return The stream source if the stream can be found.
@throws DataException in case of a IO error or stream volume not visible or nonexistent.
stroom-data/stroom-data-store-impl-fs/src/main/java/stroom/data/store/impl/fs/FsStore.java