Wanting to distribute program as a framework, but worried about number of dependencies

Question

I have a project right now that straddles the line on framework and pluggable program, and am worried about the sheer number of dependancies that this program rely's on.

Currently I have this:

• Commons lang - Mainly for string utils and array utils
• slf4j - Logging facade
• slf4j-log4j - Redirects logging to log4j for GUI (note that the GUI is a module)
• log4j - Log4j itself for the above reason
• jpersist/EJP - Database abstraction layer
• PircBot - IRC layer
• A JDBC driver
• Mozilla Rhino - For Javascript plugins

In all that totals 7, even without the GUI unless you don't want any logging. For me who's trying to pass this off as "lightweight", this seems like way too much.

So my questions:

1. Should I limit the amount of frameworks that I am using?
2. How should I distribute it? Would an independent jar for being used in other programs and a big combined jar for a single program be okay?
3. Is this many dependencies normal?

Answer 1

It does seem like quite a lot. Regardless of the issue of specifying numerous libraries, you're restricting your users wrt. the third-party libraries they can use in their project to the ones you specify.

Can you specify implementation-agnostic libraries ? e.g commons-logging, which will delegate to existing logging frameworks under the covers. If your users are already using something other than log4j, then this will permit them to carry on without having to switch.

Secondly, is your framework doing too much ? Instead of providing a chat implementation, why not provide a suitable API such that clients can plug in their own chat/notification mechanism. That way your framework becomes more generic and (again) your clients can choose what/how to implement features. A rich client API will give your users many more options and extend the usefulness of your framework.

Answer 2

the scale of your project ie what it accomplishes and in what environment it will be used will balance out against how many dependencies and ease of configuration in general when people assess the suitability of your project.

you haven't really hinted at what your project attempts to achieve so it's difficult to say whether you have a bloated stack. however, for something reasonably useful I personally wouldn't have a problem with most of those jars.

the only thing that rings alarm bells is the database layer and the jdbc driver. if your project is a 'framework' i fail to see how a particular jdbc driver fits the model, and persistence in general does not quite fit the model of a framework.

Answer 3

Should I limit the amount of frameworks that I am using?

If you are really using/needing them, not really. I would just try to avoid overlapping libraries and adding a library if you're only using 1% of it.

How should I distribute it? Would an independent jar for being used in other programs and a big combined jar for a single program be okay?

Many projects are distributed as a zip/tar.gz distro. But for a framework, making it available as a Maven artifact would be a great plus (in which case, make log4j and the log4j binding optional).

Is this many dependencies normal?

Firstly, you don't have that many dependencies. Secondly, there is IMO nothing wrong with reusing a logging facade, a persistence library, utility classes, etc (not using such libraries and writing your own code to replace them would be stupid). Thirdly, most users don't care, especially if you are delivering nice features (instead of spending time reinventing the wheel and, ultimately, creating bugs).

Answer 4

That might seem like a lot of dependencies, but I don't think it is in reality. Certainly, there doesn't seem to be much gratuitous duplication of functionality. Most of the dependencies are doing things that you'd otherwise need to implement yourself.

For me who's trying to pass this off as "lightweight", this seems like way too much.

Maybe you need to adjust your rhetoric. :-)

Seriously, if those dependencies are necessary, the only way you will be able to get rid of them is to either code equivalent functionality yourself (bad idea) or drop the corresponding functionality (maybe a bad idea). Which is more important to you; being lightweight or being functional?

EDIT

Functional is key in the end. I can have my own custom implementation of everything but it would be full of bugs I guess. However I would like to keep it small as small and easy do attract people.

Well you clearly understand the issues. The decision is yours to make. (But don't forget that while some people are put off by "bloat", others are attracted by lots of functionality.)

I suppose that there is a half-way solution. Keep the functionality, but make it optional and provide some way that people can configure it in / out. Of course, the downside is that this means that you have to test multiple permutations of configuration options, and it makes installation / configuration more complicated for your users.

Answer 5

I think you worry to much :) The number of dependencies is not relevant, the maturity of them it is. If you will drop functionality/usability/flexibility/etc just because you want to keep the number of dependencies "low" it would be a loss for you (and your clients).