[rules-users] Challenge! Using javassist and drools presents an issue with drl

[Mark Proctor]

  On 29/04/2010 09:38, Swindells, Thomas wrote:
> Isn't the simplest solution just to add the imports at the start of the imported drl file?
> That is the users don't need to worry about writing the imports but before you feed the files into your code simply prepends the required imports.
>
> You can do this easily in memory with something like the following:
> StringWriter drlContents = new StringWriter();
> drlContents.write("import ...\n");
> FileInputStream stream = new FileInputStream(drlFile);
> InputStreamReader inR = new InputStreamReader(stream, "UTF-8");
> IOUtils.copy(inR, drlContents);
> kbuilder.add(ResourceFactory.newReaderResource(new StringReader(drlContents.toString())),                             ResourceType.DRL);
Make sure you generate the classes first and put them into a 
classloader. Then specify that ClassLoader as the root classload to the 
kbuilder and kbase configurations.

Mark
> Thomas
>
>> -----Original Message-----
>> From: rules-users-bounces at lists.jboss.org [mailto:rules-users-
>> bounces at lists.jboss.org] On Behalf Of Dave Cracauer
>> Sent: 28 April 2010 19:35
>> To: Rules Users List; rules-users at lists.jboss.org
>> Subject: Re: [rules-users] Challenge! Using javassist and drools presents an
>> issue with drl
>>
>>
>> It sounds like the stated goal is to make things easier for non-developers to
>> write rules. What about a dsl?
>>
>> What about using a templating language?  I have used velocity in the past for
>> dynamically generating rules based on templates, and I think that there is
>> built in support for templates using mvel.
>>
>> -----Original Message-----
>>> From: markricard<markricard at gmail.com>
>>> Sent: Apr 28, 2010 11:53 AM
>>> To: rules-users at lists.jboss.org
>>> Subject: Re: [rules-users] Challenge! Using javassist and drools presents an
>> issue with drl
>>>
>>> Perhaps there is an easier way to ask this question....
>>>
>>> Rather than having to do an 'import' of a class in a drl text file, is there
>>> a way in the Java code that constructs the KnowledgeBase to via java
>>> dynamically import any class file required by any drl file that is added?
>>>
>>> Instead of the drl having:
>>>
>>> import com.foo.Instance;
>>> rule "Walgreens Test"
>>>     ....
>>>
>>> It just has:
>>>
>>> rule "Walgreens Test"
>>>     ....
>>>
>>>
>>> And in the KnowledgeBuilder does something like this:
>>>
>>> KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
>>> kbuilder.addImport("com.foo.Instance");
>>> ...
>>>
>>>
>>>
>>> --
>>> View this message in context: http://drools-java-rules-
>> engine.46999.n3.nabble.com/Challenge-Using-javassist-and-drools-presents-an-
>> issue-with-drl-tp763086p763118.html
>>> Sent from the Drools - User mailing list archive at Nabble.com.
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