State flow in java

Question

I have a state history table, which contains states of an activity. These states can be repetitive. Sample table :

id    activity_name   state     sub_state
1      firstTask       Check     INPROGRESS
2      firstTask       Check     FAIL
3      secondTask      Check     INPROGRESS
4      secondTask      Check     SUCCESS
5      seccondTask    Initiated  INPROGRESS
6      secondTask     Initiated  SUCCESS

Any new activity with new state can be introduced anytime in the system.

These states in the table are for debugging purpose. Now I need to expose an API which reads this table and convert these states to meaningful states ignoring the repetitions.

Eg, the above table should be exposed as

First TASK: 
CHECKED --> FAILED

Second Task:
CHECKED --> INITIATED

What approach/design pattern should I follow which will handle newly introduced states, their compaction and conversion to meaningful state.

Thanks in advance.

do you have to search after states or substates, and could we change the table, too? — Kordi, Mar 07 '16 at 12:18
Have a look at : http://stackoverflow.com/questions/34341587/how-can-i-add-states-to-my-game/34341970#34341970 — Ravindra babu, Mar 07 '16 at 13:53

Kordi · Answer 1 · 2016-03-07T12:30:23.023

Unusal Approach

If you dont have queries like: Give me all Task which state is check and substate is failed try this approach. Save the state and substate in a json string in the database.

id    activity_name   state
1      firstTask      {'Check' : ['INPROGRESS', 'FAIL']}
2      secondTask     {'Check' : ['INPROGRESS', 'SUCCESS'], {'Initiate' : ['INPROGRESS', 'SUCCESS']}

Relational Approach

If you like it the rational way then try to save it like that way, or the criteria above don't fit.

id    activity_name   state     sub_state
1      firstTask       Check     01-INPROGRESS
2      firstTask       Check     02-FAIL
3      secondTask      Check     01-INPROGRESS
4      secondTask      Check     02-SUCCESS
5      seccondTask    Initiate   01-INPROGRESS
6      secondTask     Initiate   02-SUCCESS

So you can just have sql queries like

SELECT MAX(SUB_STATE) FROM STATES WHERE activity_name = 'firstTask' and state = 'Check';

Max is here a string comparison, so if you have more than 99 sub_states for one state then use 003-SUCCESS, etc. You can use normal int number too, but than its hard to read the table without further knowledge from the sql console. So if data size doesn't matter I would prefer to append the meaningful string.

In both approaches you can easily introduce new states.

Actually sub_state are more then INPROGRESS or FAIL, sub_state will many times save the 1 level high description of corresponding state. Also my table can have more than 10 dynamic task, getting max will not be possible in that case — Mak, Mar 08 '16 at 06:52
@Mak thats true but thats no problem at all. Then you just create a new one. In both approaches you can create unlimited substates. the 01- infront is just which substate for this state occured first, that you can have a nice query optimization. Max(SUB_STATE) for a state is than just the last substate for this state which occured. You know what I mean? — Kordi, Mar 08 '16 at 07:08

State flow in java

1 Answers1

Unusal Approach

Relational Approach