11:28 p.m.
I've been reading about spring this weekend, in preparation of spring
support for drools-api. My first attempt was using drools-api factories
directly, which actually works "out of the box". Here is an example
using the KnowledgeAgentFactory:
--------beans.xml-------
<bean id="agent1"
class="org.drools.agent.KnowledgeAgentFactory"
factory-method="newKnowledgeAgent">
<constructor-arg type="java.lang.String" value="agent1"/>
<constructor-arg type="java.util.Properties">
<props>
<prop
key="file">src/main/java/org/drools/springframework/testSpring.drl</prop>
</props>
</constructor-arg>
</bean>
---------testSpring.drl---------
package org.drools.springframework
rule "rule 1"
when
then
System.out.println( "hello world" );
end
---------test---------
Resource resource = new FileSystemResource(
"src/main/java/org/drools/springframework/beans.xml" );
BeanFactory factory = new XmlBeanFactory( resource );
KnowledgeAgent agent1 = ( KnowledgeAgent ) factory.getBean( "agent1" );
agent1.getKnowledgeBase().newStatelessKnowledgeSession().executeObject( "test"
);
Sow I was quite impressed how easy that was to get working, but people
like the "Spring" way. So I made a custom SpringKnowledgeAgentFactory
that implements FactoryBean. So now the above beans.xml can look like
the following:
<bean id="agent1"
class="org.drools.spring.SpringKnowledgeAgentFactory">
<property name="name" value="agent1"/>
<property name="file"
value="src/main/java/org/drools/spring/testSpring.drl" />
</bean>
Which is much less verbose. So I think I'll take some time tomorrow to
do FactoryBean implementations for all main user factories from
drools-api, shouldn't take long and then we have out of the box spring
support. Anyone have any feedback, it seems that now that we have
drools-api, which provides complete implementation/interface separation,
and Spring only needs to return interfaces, this is all we need to do.
If it's quick to do, I might have a go at doing one for Guice too.
Mark
5:08 a.m.
Strong opinions:
org.drools.spring.SpringKnowledgeAgentFactory
should be renamed to
org.drools.spring.SpringKnowledgeAgentFactoryBean
See "All Known Implementing Classes" in:
http://static.springframework.org/spring/docs/2.5.x/api/org/springframewo...
Weak opinions:
I'd also maybe consider dropping the Spring prefix, as it's in a package
called spring?
=> org.drools.spring.KnowledgeAgentFactoryBean
How are you going to name the module? Like they do in Seam?
=> module with artifactId "drools-ioc"
See http://repository.jboss.org/maven2/org/jboss/seam/jboss-seam-ioc/
With packages like this?
org.drools.ioc
org.drools.ioc.spring
org.drools.ioc.guice
org.drools.ioc.picocontainer
...
=> org.drools.ioc.spring.KnowledgeAgentFactoryBean
It helps to understand it's purpose if it follows naming conventions of
other projects :)
With kind regards,
Geoffrey De Smet
Mark Proctor schreef:
7:41 a.m.
Geoffrey De Smet wrote:
ok, will do.
My worry here is it might be a
duplicate of the same name used in the
future - although it'll be in a different package namespace, it's still
not good practice. Anyone else have any opinions on this?
I'd just
done drools-spring, do you recommend something else? then guice
would just be org.drools.guice.
I didn't know what other projects do, so if this is a
convention that
other people expect, i.e. more than just Seam, then I think we can do it.
Mark
12:19 p.m.
Geoffrey De Smet wrote:
I'm just wondering about
KnowledgeBuilderFactory and
KnowledgeBaseFactory. While it makes sense to put the
KnowledgeAgentFactory into spring, does it make sense for those other
factories? What are they gonna do other than return KnowledgeBuilder or
a KnowledgeBase, only possible advantage is that it would allow spring
to inject the KnowledgeBuilderConfiguration and
KnowledgeBaseConfiguration. And ideas?
http://anonsvn.labs.jboss.com/labs/jbossrules/trunk/drools-api/src/main/j...
http://anonsvn.labs.jboss.com/labs/jbossrules/trunk/drools-api/src/main/j...
http://anonsvn.labs.jboss.com/labs/jbossrules/trunk/drools-api/src/main/j...
http://anonsvn.labs.jboss.com/labs/jbossrules/trunk/drools-api/src/main/j...
This is typically how those two factories are used:
KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
kbuilder.addResource( new URL( "file://myrules.drl" ),
KnowledgeType.DRL);
KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
If we use spring to automate the adding of resources, that's pretty much
what the agent is doing anyway, so wouldn't that be pointless?
Mark
2:15 p.m.
It doesn't indeed sound overkill to me to create a FactoryBean for the
Builder.
Though I would probably reuse the Builder inside the
KnowlegdeBaseFactory to build the Knowlegde base.
The real issue is concurrency.
Spring promotes the idea of stateless beans which do have global
variables, but those global variables are either synchronised
thread-safe or also follow the stateless bean pattern.
This in fact makes the stateless beans thread safe, without any need for
synchronization/locking.
So the question is: is your KnowlegdeBase thread-safe?
Thread safe objects are usually put into global variables,
while not thread unsafe objects are always put into local variables.
class A {
private B b; // thread-safe by synchronization (JDBCConnection, ...)
private C c; // thread-safe by the stateless pattern:
// both b and c are set during initialization (constr. or setter),
before A is exposed to other threads
public void metho(D d) { // d is not thread-safe
E e = ...; // e is not thread-safe
}
}
In drools 4. B is the RuleBase, while E is the working memory instance.
With kind regards,
Geoffrey De Smet
Mark Proctor schreef:
8:17 p.m.
now my spring skills are improving, I'm looking to improve the xml and
leverage spring Resource framework - so that we can get complete
scripting of the entire KnowlegeBuilder api. I've come up with the two
xmls so far:
<property name="drls">
<list>
<value>file:src/main/java/org/drools/ioc/spring/testSpring.drl</value>
</list>
</property>
<property name="dtables">
<list>
<bean
class="org.drools.ioc.spring.DtableResourceFactoryBean">
<property name="resource"
value="file:src/main/java/org/drools/ioc/spring/dt.xls" />
<property name="inputType" value="XLS" />
</bean>
</list>
</property>
This one has a property per knowledge type, the advantage is on
knowledge types which are just string, we can use a simple <value>.
Although knowlege tyep that require additional information, like the DT
input type, will need a bean.
<property name="resources">
<list>
<bean
class="org.drools.ioc.spring.KnowledgeResourceBeanFactory">
<property name="knowledgeType" value="DRL" />
<property name="resource"
value="file:src/main/java/org/drools/ioc/spring/testSpring.drl"
/>
</bean>
<bean
class="org.drools.ioc.spring.KnowledgeResourceBeanFactory">
<property name="knowledgeType" value="DTABLE"
/>
<property name="resource"
value="file:src/main/java/org/drools/ioc/spring/dt.xls" />
<property name="resourceConfiguration">
<bean
class="org.drools.ioc.spring.DtableResourceFactoryBean">
<property name="inputType" value="XLS"
/>
</bean>
</property>
</bean>
</list>
</property>
This approach more closely resembles the kbuilder api. We have simple
resources list. Everything is a bean, so it's very flexible, but we lose
the shortcut approach of the first one where we can just give a list of
strings. As each one must be a bean, so that it can contain atleast the
knowledge type, as well as the resource string.
My preference currently is for the second one, as I don't tink it's too
verbose, and it provides better consistency than the first.
Mark
Geoffrey De Smet wrote:
9:09 p.m.
I'm thinking of adopting the Spring approach to Resources for
drools-api, obviously not tieing drools-api to spring - just copying the
concept. Resource however doesn't seem to work with Readers. Readers in
general are only needed for in memory generation , using StringReader,
otherwise file/url/classpath resources suffice. So it seems to do the
Spring way you would do a ByteArrayResource( "this is my drl
file".getBytes() ). I'm wondering what people think of that, and what
about encoding issues? Compared to the way at the moment that we just
take a Reader, and that's it.
Mark
Mark Proctor wrote:
11:13 p.m.
Well, if you look at String.getBytes() it uses the default encoding, then ISO-8859-1 if
that fails. (Default is UTF-8 unless otherwise specified in the "file.encoding"
property.) As long as that's documented I guess it's not a problem, unless someone
wants to specify their own charset for a particular file. Java 1.6 has
String.getBytes(Charset) and that could allow someone to use an alternate charset.
I figure for the vast majority of cases it won't be a problem.
--- On Sun, 11/23/08, Mark Proctor <mproctor(a)codehaus.org> wrote:
11:42 p.m.
I'm updating drools-api as we speak, based on the spring Resource idea.
the following Factory will provide a set of ready to go Resources, that
should satisfy most people's needs. So drools-api will be spimplied to
kbuilder.addResource( Resource, KnowledgeType )
kbuilder.addResource( Resource, KnowledgeType, ResourceConfiguration )
And the Resources available, and ofcourse people can implement the
interface themselves is:
public class ResourceFactory {
public static Resource newURLResource(URL url) {
return null;
}
public static Resource newURLResource(URI uri) {
return null;
}
public static Resource newURLResource(String url) {
return null;
}
public static Resource newFileResource(File file) {
return null;
}
public static Resource newFileResource(String file) {
return null;
}
public static Resource newByteArrayResource(byte[] bytes) {
return null;
}
public static Resource newInputStreamResource(InputStream stream) {
return null;
}
public static Resource newReaderResource(Reader reader) {
return null;
}
public static Resource newReaderResource(Reader reader, String encoding) {
return null;
}
public static Resource newClassPathResource(String path) {
return null;
}
public static Resource newClassPathResource(String path, ClassLoader classLoader) {
return null;
}
}
It can take a Reader, which underneath will open an InputStream, it'll use default
encoding unless the encoding is
specified as otherwise in the alternative param.
So typically it'll be
kbuilder.addResource( ResourceFactory.newClassPathResource( "some path" ),
KnowledgeType.DRL );
don't forget you can import static methods, so it can actually be:
kbuilder.addResource( newClassPathResource( "some path" ), KnowledgeType.DRL );
Mark
Greg Barton wrote:
12:07 a.m.
This is now what the spring XML looks like:
<bean id="rb1"
class="org.drools.ioc.spring.KnowledgeBaseFactoryBean">
<property name="resources">
<list>
<bean
class="org.drools.ioc.spring.KnowledgeResourceFactoryBean">
<property name="knowledgeType" value="DRL" />
<property name="source"
value="file:src/main/java/org/drools/ioc/spring/testSpring.drl"
/>
</bean>
<bean
class="org.drools.ioc.spring.KnowledgeResourceFactoryBean">
<property name="knowledgeType" value="DTABLE"
/>
<property name="source"
value="file:src/main/java/org/drools/ioc/spring/IntegrationExampleTest.xls"
/>
<property name="knowledgeResourceConfiguration">
<bean
class="org.drools.ioc.spring.DTableResourceConfigurationFactoryBean">
<property name="inputType" value="XLS"
/>
</bean>
</property>
</bean>
</list>
</property>
</bean>
How is that looking? Most people happy with that, it's very generic.
I've dropped the agent side for the moment, just focusing on scripting
of a KnowledgeBase via spring. It now more closely follows the
KnowedgeBuilder api. The above spring configuration will return a
rulebase of two resources, on is a simple DRL, the other is a
decisiontable of type XLS.
I'll extend this further to make sure that ALL knowledge types can be
built for a knowledge base via the spring api. I'll also make sure it
can take a KnowledgeBaseConfiguration and KnowledgeBuilderConfiguration.
Then I'll also make sure there is a spring configuration to return a
stateful or stateless session given a knowlebasefactorybean ref. Finally
I might add some basic agent facilities.
I think this should give spring users everything they need, i.e. the
capability to build knowledge bases and wire sessions and knowledge
bases to other beans - all via xml.
Mark
Mark Proctor wrote:
5:51 a.m.
Hi,
I think the xml looks good.
Spring's PropertyEditors -
http://static.springframework.org/spring/docs/2.5.x/reference/validation....
could
be used to even further simplify it. Using convention over configuration to
guess the resource type from file's extension. The configuration will then
become:
<bean id="rb1"
class="org.drools.ioc.spring.KnowledgeBaseFactoryBean">
<property name="resources">
<list>
<value>
file:src/main/java/org/drools/ioc/spring/testSpring.drl</value>
<value>
file:src/main/java/org/drools/ioc/spring/IntegrationExampleTest.xls</value>
</list>
</property>
</bean>
I am not that familiar with PropertyEditors to know if this is possible to
do or not. I am just throwing it out here, maybe somebody else will know
better. It is not that important just nice to have..
Best Regards,
Michal
On Tue, Nov 25, 2008 at 6:07 AM, Mark Proctor <mproctor(a)codehaus.org> wrote:
10:02 a.m.
I'm going to get the basics done, then I'm really hoping that you or
paul or someone else will pick up the rest and polish it off (like your
suggestion below) and do javadocs - as I need to get on with core work -
I'm just trying to get the ball rolling.
I'll try and have something committed today, that you people can roll with.
Mark
Michal Bali wrote:
5964
days inactive
5967
days old
13 comments
4 participants
participants (4)
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Geoffrey De Smet -
Greg Barton -
Mark Proctor -
Michal Bali