Currently there are classes ZCL_ABAK_CONTENT_CUSTOM and ZCL_ABAK_FORMAT_CUSTOM. Their sole function is to set GET_TYPE() = CUSTOM. This doesn't do much. So I'll simplify things by getting rid of these.
So, in order to make a new _CONTENT one will inherit from abstract class ZCL_ABAK_CONTENT as all the other _CONTENT classes. And to make a new _FORMAT one will implement interface ZIF_ABAK_FORMAT as all the other _FORMAT classes.
Currently there are classes ZCL_ABAK_CONTENT_CUSTOM and ZCL_ABAK_FORMAT_CUSTOM. Their sole function is to set GET_TYPE() = CUSTOM. This doesn't do much. So I'll simplify things by getting rid of these.
So, in order to make a new _CONTENT one will inherit from abstract class ZCL_ABAK_CONTENT as all the other _CONTENT classes. And to make a new _FORMAT one will implement interface ZIF_ABAK_FORMAT as all the other _FORMAT classes.
Simpler is better.