Re: [Jython-dev] Simple java class import #2

[Samuele P. <pe...@in...>]

From: Oti <oh...@ya...>
> Hello Samuele,
> 
> please find below my second approach, hopefully closer to your
> requirements.
> I'd like to hear your comments before I flush the SF package manager
> with more code.
> 
> This approach:
>   - keeps the precedence 'python over java'
>   - does not load any classes
>   - IMHO is at the highest level possible 

[sad] this kind of patch should go at the lowest possible
level. I remember to have written that it should probably go
at the PackageManager level or just a level above.
The kind of hack to check the exception kind
is a good signal that it is not the right level to do this,
it is too late in the game.

Nothing personal. I'm  really sorry.

I will work on this and maybe other import
improvements before EuroPython.
Is the least I can do...


>   - passes test/test_import.py from the CPython 2.1.3 distribution
>   - passes test/dynamic_import.py
>   - allows package imports, too
>   - enables fixing a bug
> 
> The idea is still the same:
> If (for whatever reasons) a java package was neither scanned nor added
> with sys.add_package(), we add it dynamically, after all other imports
> failed.
> 
> There is a unittest attached (dynamic_import.py) which I expect to fail
> with standard jython 2.1 (ImportError: no module named dynamic), while
> it should succeed with the changes to imp.java and __builtin__.java
> attached and described below.
> In order to run this test, please add dynamic_import.jar to the
> classpath, but do not add dynamic_extension.jar. Both jars have to be
> in the same directory, though.
> 
> As a second step, you could disable the package scan (patch No. 525092;
> safely leave the .py files untouched) and delete the cachedir. Again
> the test should pass!
> 
> Thank you very much for your time reviewing this.
> Best wishes,
> Oti.
> 
> 
> 
> imp.java ( 'Release_2_1' = revision 2.59 )
> ------------------------------------------
> 
> - add the constant:
>     String NO_MODULE_NAMED = "no module named ";
> - replace the two "N/no module named" strings with this constant:
>     throw Py.ImportError(NO_MODULE_NAMED + name);
> - add the two methods isJavaClass() and isJavaPackage()
> 
> 
> __builtin__.java ( 'Release_2_1' = revision 2.41 )
> --------------------------------------------------
> 
> There are only changes to class ImportFunctions:
> - in method __call__(), replace load() with dynamicLoad()
> - add the methods:
>     dynamicLoad(),
>     findJavaPackage(),
>     getFirstFrom(),
>     eliminateNoneModules()
> 
> 
> 
> 
> While developing the above I was able to fix a funny bug. Consider the
> following situation:
> 
> 1) somewhere on the classpath,
>    there is aClass.class in package p1.p2:
>      /p1
>        +--  /p2
>               +- aClass.class
> 
> 2) somewhere on sys.path,
>    there is aModule.py in directory /m1,
>    and /m1 has an empty subdirectory /p1:
>      /m1
>        +--  aModule.py    contains 'from p1.p2 import aClass'
>        +--  __init__.py   empty
>        +--  /p1           empty directory
> 
> Now 'import m1.aModule' with the embedded 'from p1.p2 import aClass'
> fails, while a plain 'from p1.p2 import aClass' succeeds.
> There is a unittest attached (blocking_import.py) which exposes exactly
> this situation. In order to run it, please copy javac.py from the
> /Tools/jythonc directory to the /Lib directory. I expect it to fail
> with standard jython 2.1 (ImportError: No module named p2), while it
> should succeed with the fixes to PyJavaPackage.java described below.
> However, I have no experience in importing java classes from sys.path,
> so this might break some of your tests ?
> 
> 
> 
> PyJavaPackage.java ( 'Release_2_1' = revision 2.17 )
> ----------------------------------------------------
> 
> in method __findattr__(), replace:
> 
>   if (__mgr__.packageExists(__name__,name)) {
>       __mgr__.notifyPackageImport(__name__,name);
>       return addPackage(name);
>   }
> 
> with
> 
>   if (__mgr__.packageExists(__name__,name)) {
>     //check if it really is a java package
>     String testPackage = "";
>     if (__name__ != null && __name__.length() > 0)
>       testPackage = __name__ + "." + name;
>     else 
>       testPackage = name;
>     if (imp.isJavaPackage(testPackage)) {
>       __mgr__.notifyPackageImport(__name__,name);
>       return addPackage(name);
>     } else {
>       Py.writeDebug("import",
>                     "'" + testPackage + "' is not a java package.");
>     }
>   }
> 
> 
> 
> __________________________________________________
> Do You Yahoo!?
> Yahoo! - Official partner of 2002 FIFA World Cup
> http://fifaworldcup.yahoo.com