jar installation standards

[Nic Ferrier]

Per Bothner <per@bothner.com> writes:

> There are two approaches that appeal to me: 
>  
> (1) Just add every .jar in $prefix/share/java to the implied 
> (boot-)classpath.  I.e. we treat the directory like Sun treats 
> its extensions directory.  The advantage is simplicity for 
> installers, users, plus compativility with Sun's model. 
> The disadvantage is that one could imagine hundreds of jars 
> being installed, and opening and reading the directory of each of 
> these could be slow.  On the other hand, if we only need to do the 
> search at compile-time, perhaps its not a big deal.  Plus we can use 
> some heuritcs, perhaps built into gcj, to only open a jar if we 
> think we might need it (e.g. after searching libgcj). 
>  
> One complication is dealing with symlinks and versioning.  If the 
> dirctory contains servlet-2.3.jar,  servlet-2.1.jar, servlet-2.jar, 
> and servlet.jar (a symlink); the compiler should pick the least 
> specific one, i.e. servlet.jar, and skip the others. 
>  
> (2) Use package-style names, similar to what we do for .so files. 
> The search algorithm when searching for class foo.bar.Baz: 
> - Search the user classpath. 
> - Search libgcj.jar. 
> - Look for foo-bar.jar; if found search it.  Otherwise, look for 
> foo.jar, and if found search it.  The compiler should explicitly 
> resolve symlinks (rather than have the OS do it) in case two symlinks 
> (eg foo-bar1.jar and foo.bar2.jar) point to the same file. 

How about a variation on the first one? 

  Provide a variable EXTENSIONPATH which contains a list of the
  directories which include extensions. Each jar file in each
  extension directory is loaded on demand.

There would be a default EXTENSIONPATH which would be:

  /usr/share/java:/usr/local/share/java


What I would *really* like is just an -extpath option on the command
line where I could specify a path. An extpath is easily constructed.


Btw, it's also pretty easy to construct an extpath from a classpath,
I use this:


  gcj -classpath `ls /usr/local/share/java/*.jar | tr [:space:] :`


Nic