Equals method for Unit

[axgdev]

Hi!

First of all thanks for the hard work put into this game! It has been very useful for my research

I have faced the problem that if I were to look for example a Unit in a map, there is a lack of an equals method that helps me to find this unit. There are workarounds like using the UnitID, or by using a wrapper class over the Unit that has an equals method, but I think the most ideal solution is to have an equals method directly in the code.

Do you think this makes sense?

[santiontanon]

Hi!

I thought this would be a great idea, so, I added it. But then I realized why didn't I have that "equals" method in the first place. A few of the AIs assume that such method does not exist, and use the "contains" method of the Java containers to see if a specific instance of a unit is there or not (assuming that the equals method is not implemented). So, adding the "equals" method breaks many AIs unfortunately...

I still think it's a good idea, and I will keep this issue open to remind myself to go through the AIs that break when the "equals" method is added and see if there is an easy way to fix them (replacing the "contains" call by a search loop, or something like that). I'll report back!

[axgdev]

That is true, it was exactly my problem when using the AbstractionLayer so I went to use the unit ID instead of the instance. I have also noticed that in previous versions of the code you have commented out the equals in the Unit, so you must have had a good reason for it.

My analysis about the problem is that a unit could have an equals if there is no property that depends on the state. In the current Unit class there are several properties that depend on the state, namely: x, y and resources (I assume the unit_type cannot be changed during the game). For that reason it would require a major rewrite for it to work, because then the units would become simple entities and the gameState would be responsible to mapping the units to their state.

You already have part of it in place because you have a function getPosition() that would get the position from the state without asking the unit. So you would need to delete the x, y properties and add a method for getting the resources of that unit, and making the gameState responsible for knowing how many resources does this unit have.

I don't know if from a game design standpoint, having simple entities and global state in the gameState is better as having entities that hold state, as I have not programmed a complex game myself

[axgdev]

To be honest I am not sure if it is worth the effort.. I would have had an easier time if it was that way, but if the rest of the researchers working with this game understand that you should just save the ID of a unit instead of the reference, then the problem is with me only 😅