Filter methods

• As objects, filters implement a number of methods

• filter() is the main method, it is called each time a chunk of data is received

• Other methods are available:

  • init() is called once, when the filter is created

  • start() is called before the first chunk of data is received. It can be used for per message initialisation.

  • end() is called after the last chunk of data has been received. It can be used for per message cleaning up.