@Override
    public String toString() {
        final StringBuilder sb = new StringBuilder();
        for (final long id : metaMap.keySet()) {
            final Meta meta = metaMap.get(id);
            sb.append(meta);
            sb.append("\n");
        }
        return sb.toString();
    }
Turns a data row object into a generic map of attributes for use by an expression filter.
stroom-meta/stroom-meta-mock/src/main/java/stroom/meta/mock/MockMetaService.java