I want to know this code can play what role in the strategy...Can you explain it in detail?

public void onStart(IContext context) throws JFException {}
public void onAccount(IAccount account) throws JFException {}
public void onMessage(IMessage message) throws JFException {}
public void onStop() throws JFException {}
public void onTick(Instrument instrument, ITick tick) throws JFException {}
public void onBar(Instrument instrument, Period period, IBar askBar, IBar bidBar) throws JFException{}