I was wondering if anyone had any experience getting data with 3270 protocol. So far I understand:
Communication
I need to connect to the SNA server using telnet, issue a command, after which some data will be returned. I am not sure how this connection is created, since I read that the standard telnet connection will not work. I also read that IBM has a library that will help, but did not go so far as to learn more about it.
Syntactic
I assumed that the returned data would be a string of 1920 characters, since the 3278 screen was an 80x24 character. I just needed to analyze these characters in the appropriate fields. The more I read about protcol 3270, the less it looked like this - I read in the documentation provided with the Jagacy 3270 Java library trial version that the attributes were marked in the protocol with char 'A' before the attribute, and I understand that there are more characters denoting other factors, such as editable fields.
I am sure that my thoughts were too simplistic. Take an example, for example, a screen containing a list of elements - pressing a special key on one of the 24 visible lines is reduced to more detailed information about this line.
I was also asked to issue print commands. This has some positive consequences - if the format of the returned string is not 1920, since it contains these characters, such as "A", indicating how users interact with the terminal, printing will destroy them. In addition, it would no longer display on a large amount of data. The flip side - I do not know how to return data from the print command back to Java.
So..
SNA, , , , . , , . - , ?