Creating query extensions

To create business-specific query predicates that process customized rule project items and properties, you extend the query BOM files.

To extend the query BOM:

1. Create a BOM file (a file with the extension .bom). In this file, define only new elements.

   For example, you can define a BOM file named ext.bom and then add a query predicate to do queries on rules that are ready for review:

   
   package bql;
   public class RuleArtifact extends bql.PackageElement
   {
   public boolean isReadyForReview()
      property categories “teamserver,rulestudio”;
   }
   

   The categories teamserver and rulestudio indicate that this query predicate can be used in both Decision Center and Rule Designer.

   Note: If your query predicate applies to extended rule model elements, set the package to bqlExtension in the BOM file.
2. Create a vocabulary file corresponding to your query BOM extensions.

   For example, you can define a vocabulary file named ext.voc as follows:

   
   bql.RuleArtifact.isReadyForReview()#sentence.navigation =
                                                   {this} is ready for review
   

   You can have several vocabulary elements for a single BOM element, and you can create a vocabulary file per locale.

3. Create an extender class. Pass an instance of IlrQueryableElementWrapper as an argument for the methods you define.

   With the interface IlrQueryableElementWrapper, you can use the methods getModelElement, setPropertyValue, and getPropertyValue on rule model elements.

   As long as you use the common interface of the rule model API to define your new methods, you can use the same code for both Rule Designer and Decision Center. You can use the Rule Designer or Decision Center model APIs for more advanced cases, but in this case your code is different for Rule Designer and Decision Center.

   For example, to write code to identify that a rule that is ready for review when its documentation field contains some content, you define the extender class as follows:

   
   public class MyExtensionClass {
      public static boolean isReadyForReview(IlrQueryableElementWrapper projectElement) {
       IlrElement modelElement = projectElement.getModelElement();
       System.out.println("isReadyForReview method called on element"+
                  modelElement.getPropertyValue("name"));
       String documentation = (String)modelElement.getPropertyValue("documentation");
       return documentation.length() > 0;
     }
   } 

4. Specify a mapping from your new BOM elements to your extender classes in a property file.

   For example, you can specify the mapping for your new BOM elements in a file named ext.properties, as follows:

   
   bql.RuleArtifact=ilog.rules.studio.samples.queryextension.MyExtensionClass
   

   In this example, MyExtensionClass refers to the fully qualified name of the extender class.