public void addCallback(String queryName, QueryCallback callback) {
        callback.setQueryName(queryName);
        callback.setContext(siddhiAppContext);
        QueryRuntime queryRuntime = queryProcessorMap.get(queryName);
        if (queryRuntime == null) {
            throw new QueryNotExistException("No query found with name: " + queryName);
        }
        callback.setQuery(queryRuntime.getQuery());
        ((QueryRuntimeImpl) queryRuntime).addCallback(callback);
    }
Get the names of the available queries.

@return string set of query names.
modules/siddhi-core/src/main/java/io/siddhi/core/SiddhiAppRuntimeImpl.java