date: 5th, June

Due to the permutation of the variables: Signed, MDN, Encrypted, MDNSigned, Synchronous MDN, there are many different types of the AS2 message. In order to send different types of messages, the AS2Message class was designed to

AS2Message Class Diagram

As shown, there are more than one send methods and all of them are static. According to this design, the Sender does not need to construct any AS2Message object, instead the Sender can directly call the proper static send method to send the message.

However this design has a few disadvantages:

• The Sender has to decide which send method to use and the corresponding message types of each send method are not defined clearly. This increases complexity of the system.
• In order to call the send method, a lot of parameters are needed. This increases complexity and/or inconvenience too.
• The Sender does not actually need to use any of the instance variables. Because the Sender passes parameters to the send method. However, the parameters and the instance variables hold the same data. This means duplication of information.

Because of the considerations above, the class has been redesigned to

New AS2Message Class Diagram