If your objects wanted to use a global cache, why not have the cache be an argument to the instantiations of all those objects? Is it because someone could still choose to instantiate another version of the cache and pass it to one of the objects? Why are the objects so dependent on having a single version of the cache, is there some special interaction where one object writes and another one reads from the cache? Why couldn’t the Cache Manager be layered on top?

I was not convinced in the need for singletons in that instance.

If your objects wanted to use a global cache, why not have the cache be an argument to the instantiations of all those objects? Is it because someone could still choose to instantiate another version of the cache and pass it to one of the objects? Why are the objects so dependent on having a single version of the cache, is there some special interaction where one object writes and another one reads from the cache? Why couldn’t the Cache Manager be layered on top?

I was not convinced in the need for singletons in that instance.

I love when you come back techie I think this article can bring a hell lot of conversation about it; some technical, but some philosophical as well.

In my opinion, Singleton is not the root of evil, that is an exemplification of the misusage of any technology after all.

Singleton can be a great tool to avoid having multiple copies of an object that it must be unique in the whole application.

For example, in the last application I wrote, we had to create a Cache Manager. This class could not be layered on top, and I needed a “singleton” access to the Cache from all objects. They should not care were a single instance of the Cache exists or not, they just want to use it, but it should be unique.

I agree that something that usually falls into the “dark side of bad habits” should be advertised as “evil” (specially for children!), but as you said… not everything is white or black

Cheers!!
Fer

I love when you come back techie I think this article can bring a hell lot of conversation about it; some technical, but some philosophical as well.

In my opinion, Singleton is not the root of evil, that is an exemplification of the misusage of any technology after all.

Singleton can be a great tool to avoid having multiple copies of an object that it must be unique in the whole application.

For example, in the last application I wrote, we had to create a Cache Manager. This class could not be layered on top, and I needed a “singleton” access to the Cache from all objects. They should not care were a single instance of the Cache exists or not, they just want to use it, but it should be unique.

I agree that something that usually falls into the “dark side of bad habits” should be advertised as “evil” (specially for children!), but as you said… not everything is white or black

Cheers!!
Fer