Question about FileManagers in Jigsaw.

[Jonathan Gibbons]

On 03/12/2012 07:09 AM, Alan Bateman wrote:
>
>>
>> Can a single javac invocation handle both legacy non-module sources and
>> sources put into a module.
>>
>> I.e.
>> javac -d bin src/com/foo/LegacyApp.java src/com.foo/com/foo/NewApp.java
>> src/com.foo/module-info.java
>>
>> And can NewApp refer to/use LegacyApp?
> Jon is best one to answer this but it should work for a single module, 
> but not multiple modules of course. 


In single module mode, the sourcepath, classpath and output directory 
should be organized as
a single package hierarchy, /without any module-name component/, such as 
"com.foo".  Thus,
module-info.java should normally be placed in top level directory on the 
sourcepath or classpath.

[Advanced note: technically module-info.java can be anywhere on the file 
system if it is always
present on the command line, as is the case for all java source given on 
the command line today,
subject to the rules about the base name of the file. But, in this case, 
you will effectively defeat
tools like the Ant <javac> task that assume a 1-1 mapping between the 
input source hierarchy
and the output class hierarchy.]

The intent is to minimize the need to reorganize the source code for 
projects that create a
single jar file (meaning no module mode) or a single jmod file (meaning 
single module mode).

Note that even in single module module, the "single" refers to the 
sources being compiled.
Even in single module mode, you can refer to other modules which have 
already been compiled
are are available on either the module path or in a module library.


If you need to compile the sources for multiple modules in the same 
compilation, then you must
use multiple module mode, which means you will need to reorganize your 
sources so that the
sourcepath and module path should be organized in "module path layout", 
meaning that there
is an extra filename component to separate the package hierarchies for 
the various modules
being compiled.  It is expected, but not required, that there is a 
relationship between the
name of that filename component and the module name.

-- Jon