8:00 – 3:30 CSIP

• Hibernate chapter 6
• Chapter 7. Learning about annotations like all the other cool kids. Done. Chapter 8 on Monday.

8:00 – 4:00 CSIP

• Hibernate Chapter 3. Working on getting to chapter 8, which covers dynamic creation. “Chapter 8 discusses criteria queries, an interesting mechanism that lets you express the constraints on the entities you want, using a natural Java API. This lets you build Java objects to represent the data you want to find, which is easier for people who aren’t database experts to understand; lets you leverage your IDE’s code completion as a memory aid; and even gives you compile-time checking of your syntax. It also supports a form of “query by example,” where you can supply objects that are similar to the ones you’re searching for, which is particularly handy for implementing search interfaces in an application.“
• Chapter 4
• Tried to change a query from foo = :upper(mySearchTerm) to foo like ‘%upper(mySearchTerm)%’ and failed completely. Dong suggested restrictions, but I don’t see how to do that in the hbm.xml <![CDATA[…]]> section.
• Chapter 5
• Chapter 6

8:00 – 4:30 CSIP

• Taking a small detour into Hibernate, to see if that can create a Java Object that Drools can operate on.
• Some relevant articles from 2008-2009, also here
• Installing hibernate eclipse plugins from here. Well I thought I was. It appears there is a conflict with Ant. Which is funny, because the book “Harnessing Hibernate” has all their examples built with Ant. It is to laugh.
• Hmm. Ant using Maven is kind of nice. Definitely more explicitly clear. it depends on maven-ant-tasks-2.0.6.jar that needs to reside in the Ant library. And if you add a link to that library as an external jar in the Ant preferences in Eclipse, it seems to work quite well.
• Well, not quite. The 2.0.6 jar only points to the default .m2/repository. You need the 2.1.3 jar if you want that to work. And that took 2 hours. Grr. Somebody should update the Safari book code repository.
• Chapter 1
• Chapter 2
• Chapter 3

8:00 – 1:30, 3:30 -6:00  CSIP

• Ok ,now that we have working(?) code, I have something to walk through while reading the book.
• The Drools team suggests that you use the joda DateTime library. It looks pretty nice, too – http://joda-time.sourceforge.net/. They also have a bunch of other interesting libraries at http://joda.sourceforge.net/
• Setting a global value in a rule
• Java

  // Import the class
  import droolsbook.bank.service.BankingInquiryService;
  
  // create the session
  static StatelessKnowledgeSession session;
  
  // create rule engine
  KnowledgeBaseConfiguration configuration = KnowledgeBaseFactory.newKnowledgeBaseConfiguration();
  KnowledgeBase knowledgeBase = KnowledgeBaseFactory.newKnowledgeBase(configuration);
  
  // declare our global
  BankingInquiryService inquiryService = new BankingInquiryServiceImpl();
  
  // make a session
  session = knowledgeBase.newStatelessKnowledgeSession();
  
  // add the global to the session
  session.setGlobal("inquiryService", inquiryService);

• Drools rule (.drl file)

  // import
  import droolsbook.bank.service.*;
  
  // declare
  global BankingInquiryService inquiryService;
  
  // use the global in a rule (note the surrounding eval(), which can evaluate any code that returns a TRUE or FALSE).
  rule "accountNumberUnique"
      when
          $account : Account(eval(!inquiryService.isAccountNumberUnique($account)))
      then
          error(kcontext, $account);
  end

• Chapter 4
• Hmm. com.ibatis.sqlmap.client.SqlMapClient looks interesting.
• After poking around, I think I found something better. Castor appears to do XML/SQL/other(?) data binding with Java. IBM appears to have a nice set of articles.
• And Hibernate may now be able to do this as well.
• Nice data visualization using webGL
• 

8:00 – 5:00 CSIP

• Went to the customer site to fill out paperwork
• Proceeding somewhat blindly is a somewhat Droolsy direction. Documentation is pretty sucky.
• Thinking about how to use rules against a database. This might require the creation of Java classes that have the structure of the table. It’s possible that this could be done with reflection, which I haven’t used since TUMMS. Here’s the Java trail just in case: http://docs.oracle.com/javase/tutorial/reflect/
• Found the source for the book: http://code.google.com/p/droolsbook/
• Reindexing maven repositories…
• had to add the following to the droolsBookParent/pom.xml in the <dependencyManagement><dependecies> section

  <dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>jcl-over-slf4j</artifactId>
  <version>1.6.0</version>
  </dependency>

• had to add the JDK to the JRE section of Eclipse Java properties. It was overriding JAVA_HOME
• Better. Maybe even good enough. The banking example is working:

  [INFO] Reactor Summary:
  [INFO]
  [INFO] Drools Book Parent ................................ SUCCESS [0.694s]
  [INFO] Banking Core ...................................... SUCCESS [3.705s]
  [INFO] Validation ........................................ SUCCESS [7.324s]
  [INFO] ETL with iBatis ................................... SUCCESS [12.815s]
  [INFO] DSL ............................................... FAILURE [4.146s]
  [INFO] Decision Tables ................................... SKIPPED
  [INFO] Ruleflow .......................................... SKIPPED
  [INFO] Stateful Rules .................................... SKIPPED
  [INFO] Complex Event Processing .......................... SKIPPED
  [INFO] Drools Flow ....................................... SKIPPED
  [INFO] Testing ........................................... SKIPPED
  [INFO] Integration ....................................... SKIPPED
  [INFO] Performance ....................................... SKIPPED
  [INFO] Sample Application ................................ SKIPPED
  [INFO] ------------------------------------------------------------------------
  [INFO] BUILD FAILURE
  [INFO] ------------------------------------------------------------------------
  [INFO] Total time: 29.097s
  [INFO] Finished at: Mon Apr 02 16:58:52 EDT 2012
  [INFO] Final Memory: 32M/199M

  [ERROR] Failed to execute goal on project dsl: Could not resolve dependencies for project droolsbook:dsl:jar:1.1-SNAPSHOT: The following artifacts could not be resolved: droolsbook:etl_iBatis:jar:tests:1.1-SNAPSHOT, droolsbook:validation:jar:tests:1.1-SNAPSHOT: Failure to find droolsbook:etl_iBatis:jar:tests:1.1-SNAPSHOT in http://www.fgmdev.com:8081/nexus/content/groups/public/ was cached in the local repository, resolution will not be reattempted until the update interval of corprepo has elapsed or updates are forced -> [Help 1]

8:00 – 4:30 CSIP

• Visualizing Drools (Visualizing Inference Process of a Rule Engine – VINCI’11, August 4–5, 2011, Hong Kong, China.)
• Onward with chapter 2
• When there is one or more Activations on the Agenda they are said to be in conflict, and a conflict resolver strategy is used to determine the order of execution. At the simplest level the default strategy uses salience to determine rule priority. Each rule has a default value of 0, the higher the value the higher the priority.
• Sheesh, had a whole slew of computer problems this morning. I was missing dlls, Some projects were pointing to debug libraries so they couldn’t distribute properly, and then my TortoiseSVN  just… evaporated. Had to reboot, reinstall, and reboot again. Everything appears to be working now though.
• Wish I could find where this tool (RuleFlow?) is hidden in eclipse
• 
• Chapter 3: Advanced Concepts and Theory
• After regular inserts you have to retract facts explicitly. With logical assertions, the fact that was asserted will be automatically retracted when the conditions that asserted it in the first place are no longer true
• It is important to note that for Truth Maintenance (and logical assertions) to work at all, your Fact objects (which may be JavaBeans) must override equals and hashCode methods (from java.lang.Object) correctly. As the truth maintenance system needs to know when two different physical objects are equal in value, both equals and hashCode must be overridden correctly, as per the Java standard.
• Chapter 4: User Guide
• ‘Hello world’ setup”

• KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();

  // Check the builder for errors
  if( kbuilder.hasErrors() ) {
      System.out.println( kbuilder.getErrors() );
      return;
  }
  
  // Resources of any type can be added iteratively
  kbuilder.add( ResourceFactory.newFileResource( "/project/myrules1.drl" ), ResourceType.DRL);
  kbuilder.add( ResourceFactory.newFileResource( "/project/myrules2.drl" ), ResourceType.DRL);
  
  if( kbuilder.hasErrors() ) {
      System.out.println( kbuilder.getErrors() );
      return;
  }
  
  Collection<KnowledgePackage> kpkgs = kbuilder.getKnowledgePackages();

• Ok, this is a nice introduction to concepts, but I’m not really getting the opportunity to build something in an kind of understandable way. There’s not much documentation, and only one book that appears to provide the overview – That’s the “Drools JBoss Rules 5.0 Developer’s Guide”. The reviews on Amazon are mixed, leaning to bad, but it’s the only game in town. I’ve bought and downloaded the Kindle edition and will try that tomorrow.