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From Neeraj Joshi <jnee...@us.ibm.com>
Subject Re: misc questions part 2
Date Thu, 03 Jan 2008 14:48:09 GMT
Hi Erik,
3) You are right. For some reason I thought you meant a GUI. 

4 & 6) I think its a great idea it will simplify the user's code. Actually 
let me take a crack
at it. So the 2 changes would be as follows: 1) The user provides a map 
with instancename -> instanceobject
and 2) the evaluator will silently ignore instances that are not imported 
inside the policy

7)  I agree XML for the customexpressions is more elegant than properties, 
I also agree about externalizing all the in-built expressions 
(acplparsermap) as an XML. Looking
forward to your patch.

8) Good point I will add the privileged blocks whereever required

9 & 13) Will look into the logging and cleaning up code

10) I think most of the places we do have statements like this:

if(logger.isLoggable(Level.FINE))
logger.fine(Thread.currentThread().getName()+" iterating over instances "
);

Is that not sufficient or have we missed putting the if in some places?

11) As a matter of fact in our original ANT build we had it built as a 
seperate jar but then while migrating to maven
in the interest of time we put it all together. Will work on seperating it 
out 

12) I suppose this is the maven convention? Again in the interest of time 
I didn't change the folder structure, do you see a 
compelling reason for this? I noticed some other projects like Apache Muse 
weren't following it either

14) I personally don't prefer the Apache Geronimo style but if everyone 
feels strongly about this I am OK with changing it.

15) Please do provide a patch.

Again we appreciate your in depth feedback!
Neeraj









3)
>NRJ: The factory is a good idea. What do you have in mind in terms of a
>user interface?

I just thought in rationalizing the current APIs and make all user exposed
methods interface based.

If I understand correctly, there are two kinds of API: User API, Service
Provider Implementation API

User API is the user view to imperius
SPI API is for instance the datastore interfaces, mostly the one in the 
external
packages.

4)
>NRJ- There is a direct correlation between the arguments passed to the
>evaluatePolicy method and the imported classes/instances within the
>policy.
>For e.g.
>
>If the import statement in the policy is as follows:
>
>Import Class a : a1,a2;
>Import Class b: b1,b2;
>
>Then the evaluatePolicy method call  would have inputMap as the parameter
>
>where
>Map inputMap =  ["a" --> instanceInfoListForA]
>                ["b" --> instanceInfoListForB ]
>
>where
>instanceInfoListForA = [instanceInfoA1  , instanceInfoA2]
>instanceInfoLIstForB = [instanceInfoB1 , instanceInfoB2 ]

IMO non declared instanceinfo objects could be silently ignored. e.g.

<source>
Map inputMap =  ["a" --> instanceInfoListForA]
                ["b" --> instanceInfoListForB ]
                ["c" --> instanceInfoListForC ]


where
instanceInfoListForA = [instanceInfoA1  , instanceInfoA2]
instanceInfoLIstForB = [instanceInfoB1 , instanceInfoB2, instanceInfoB3 ]
instanceInfoLIstForC = [instanceInfoC1 ]
</source>

B3 and C1 could be silently ignored since the policy has:

>Import Class a : a1,a2;
>Import Class b: b1,b2;

I can create a patch if you agree.

6) Simplified User API by hiding InstanceInfo?

e.g.

Map map = new HashMap();
map.put("a1", myobjecta1);
map.put("a2", myobjecta2);
map.put("b1", myobjectb1);
map.put("b2", myobjectb2);

spl.executePolicy(name,map);

Internally, PolicyManager.executePolicy can create InstanceInfo.


7) Properties Loader (customexpressions): Currently custom expressions are
configured in a property file placed at the user.dir or splhome. I propose 
the
following:

- change properties to xml format
- default naming of the file would change from 
customexpressions.properties to
imperius.xml
- imperius.xml would be loaded by default from the locations: cur.dir, 
user.dir
and splhome.
- allow configuring customexpressions via the SPLPolicyRuleProvider 
interface.
The operation void registerExpressions(InputStream xml) is added to the
SPLPolicyRuleProvider.

<imperius>
<configuration>
<spl-expression class-name="sample.SendMail"/>
<spl-expression class-name="sample.ExecuteCommand"/>
</configuration>
<imperius>

- Externalize ACPLParserMap expressions registration to another XML file:
org.apache.imperius.spl.Expressions.xml

I can also provide a patch.

8) Access to protected resources. System.getProperty, Class.forName, etc

None of the access to these resources happen in privilege blocks, so 
imperius
won't work in secured environment.

9) Cosmetic: There are plenty of messages output to system.out. These 
should be
moved to log.

10) Logging code should be enclosed within a check condition:

e.g.

if( logger.isDebugEnabled() )
{
 logger.debug(xxxx)
}

11) Samples in the JavaSPL should be moved to its own module. I propose
javaspl-samples

12) Unit tests should be moved to /src/test/

12) Sources should be moved from /src/ to /src/java/ or /src/main/

13) Cleanup code: Remove commented out code; Remove empty methods such as 
static
mains..; make classes private when possible

14) Code Formatting: use of Apache Geronimo coding style?

15) Prevent nullpointerexceptions. in some cases I got NPE, so need to 
prevent
these situations. I propose to create unit tests for the test cases I have 
and
provide a patch.

Regards


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Those are my principles. If you don't like them I have others." 
 
Neeraj Joshi
Autonomic Computing Policy Development
Tivoli, IBM

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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