void clear() {
        LOGGER.debug("Clearing XML schema cache");
        schemaSets.clear();

        for (final ClearHandler clearHandler : clearHandlers) {
            try {
                clearHandler.onClear();
            } catch (final RuntimeException e) {
                LOGGER.error("Unable to clear cache!", e);
            }
        }
    }
We will clear the schema cache if there are any changes to the schema.
stroom-pipeline/src/main/java/stroom/pipeline/xmlschema/XmlSchemaCache.java