@Deprecated
    @Override
    public Map<String, List<Connection>> filter(List<Connection> connections) {
        List<Connection> serviceOnConnections = new ArrayList<Connection>();
        List<Connection> serviceOffConnections = new ArrayList<Connection>();
        Map<String, List<Connection>> filteredConnections = new ConcurrentHashMap<String, List<Connection>>();

        for (Connection connection : connections) {
            if (isConnectionOn(connection)) {
                serviceOnConnections.add(connection);
            } else {
                serviceOffConnections.add(connection);
            }
        }

        filteredConnections.put(Configs.CONN_SERVICE_STATUS_ON, serviceOnConnections);
        filteredConnections.put(Configs.CONN_SERVICE_STATUS_OFF, serviceOffConnections);
        return filteredConnections;
    }
This method only invoked in ScheduledDisconnectStrategy, so no need to be exposed.
This method will be remove in next version, do not use this method.

The user cannot call ScheduledDisconnectStrategy#filter, so modifying the implementation of this method is safe.

@param connections connections from a connection pool
src/main/java/com/alipay/remoting/ScheduledDisconnectStrategy.java