One of the problems we ran into while fixing 6021 was the ability to use a Linked[Hash]Map. The default JDK version doesn't have any public or protected API to give us the previous and next entries. We need those to retrieve the next element when removing a child from a markup container.
Unfortunately the JDK collections don't have any extensibility that would allow us to graft those missing methods upon the existing collections. Commons Collections provides a LinkedMap class that does give us those methods. Unfortunately this forces us to add a core dependency, or we should copy the specific code into our project. Adding a dependency is bad because it adds more stuff to track--not just for us, but for our users as well--, provides additional headaches (as you may have noticed, there's an deserialization issue with commons-collections). Moving the code from com-col to Wicket is also bad, as we take on the maintenance burden, the code in question takes about 30-ish classes to copy, and we duplicate code that is available from elsewhere (duplication is bad mkay) Emond's suggestion is to move the code, strip it of all that we don't need and maintain that ourselves. I'd like to add that we should make that code package private or name it such that it doesn't conflict with com-col on a class name base. But before we go on that path, we'd like to hear if folks have better ideas? Martijn
