Jon Harvey wrote: >I must side with Craig's world view: ><snip> > >>sub-apps should be as self >>contained and independent as possible, in the same manner that webapps >>should be as self contained and independent as possible. >> ></snip> > >OO is first and foremost about encapsulation. >Your solution's objects mirror the user's mental model. > You must have missed my post about adding a switch to make it optional and default it to "off".
>Inheritance breaks encapsulation. It tightly >couples subclasses to superclasses. A subclass depends on >the implementation details of its superclass for its proper >function. If the superclass's implementation changes from >release to release, the subclass may break even though it >hasn't been touched. > >When I model I use this rule of thumb: >If inheritance isn't in the domain model, >don't have it in the implementation. > >I try to use composition over inheritance which >IMHO makes the code easier to understand. >One of the biggest mistakes for Java newbies is to >jump into inheritance and end up with an app made >up of one huge inheritance heirarchy. It is evil to >maintain - I have had to try and 'fix' quite a few. >You spend most of the day traversing the heirarchy >playing "find the implementation". It's tedious when >you have the source but becomes evil when you have >to decompile some framework's jar and find out the >inner workings of superclasses. > Ok - I see that side. You don't find polymorphism (which is kind of what we're discussing, I think) a valuable asset? I do :-) >Sorry about the rant - Joshua Bloch explains it better >as Item 14 in his book: "Effective Java Programming Language Guide" >He helped architect & write alot of Java's collection >classes which are an excellent example of how to write >an API framework. It's well worth reading. > >Hmm sorry - probably a bit more than 2 cents... >but I consider inheritance the most widely misused >feature of OO languages. > Hey - 2 cents; 10 cents ;-) I don't think anyone's counting. The point was to generate meaningful discussion. All views are important. It's really kind of moot at this point though, as I observed in my response to Martin. I now see (crystal) clearly that this discussion should be tabled until we have a 1.1 final out there. As a rebuttal however :-) I would note that inheritence is one of the (very powerful) tools of the OO paradigm. Yes, it can be misused. What can't? Ok ... I had a couple paragraphs explaining my point but I removed them (I think voicing opinions on this issue would be counter-productive at this time - sorry I started it!). Let's continue on and get 1.1 out the door and then put our heads together - fair enough? I'm sure there's someone out there wishing 1.1 were final so they could use it - and such discussions are just going to side-track us from our primary goal, which is reaching final status of 1.1. >Jon. > -- Eddie Bush -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
