E Working with Oracle Business Rules and JSR-94 Execution Sets

E.2.1 Creating Rule Execution Set with Oracle Business Rules RL Language Text

You can use JSR-94 with RL Language rulesets saved as text, where the Oracle RL text is directly included in the rule execution set. For more information, see "Using the Extended createRuleExecutionSet to Create a Rule Execution Set" for information about JSR-94 extensions that assist you in including RL Language text.

To create a rule execution set from Oracle Business Rules Oracle RL language text:

1. Specify the RL Language mapping information in an XML document. Table E-1 shows the mapping elements required to construct a rule execution set. Example E-1 shows a sample XML document for mapping RL Language text to a JSR-94 rule execution set.

2. You then use the XML document with the JSR-94 administration APIs to create a rule execution set. The resulting rule execution set is registered with a JSR-94 runtime (using a RuleAdministration instance).

<rule-execution-set xmlns="http://xmlns.oracle.com/rules/jsr94/configuration"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.0">
    <name>CarRentalDemo</name>
    <description>The Car Rental Demo</description>
    <rule-source>
        <rl-text>
         ruleset DM {
            fact class carrental.Driver {
               hide property ableToDrive, driverLicNum, licIssueDate, licenceType,
               llicIssueDate, numPreAccidents, numPreConvictions,
               numYearsSinceLicIssued, vehicleType;
            };

               final String DeclineMessage = &quot;Rental declined &quot;;

               public class Decision  supports xpath {
                  public String driverName;
                  public String type;
                  public String message;
              }

               function assertXPath(String package,
                                    java.lang.Object element, String xpath) {
                  //RL literal statement
                  main.assertXPath( package, element, xpath );
               }

               function println(String message) {
                  //RL literal statement
                  main.println(message);
               }

               function showDecision(DM.Decision decision) {
                  //RL literal statement
                  DM.println( &quot;Rental decision is &quot; + decision.type +
                              &quot; for driver &quot; + decision.driverName +
                              &quot; for reason &quot; + decision.message);
               }
         }
        </rl-text>
    </rule-source>
    <rule-source>
        <rl-text>
            ruleset vehicleRent {
                rule UnderAge {
                    priority = 0;
                    if ((fact carrental.Driver v0_Driver &amp;&amp;
                        (v0_Driver.age &lt; 19))) {
                            DM.println( &quot;Rental declined: &quot; + v0_Driver.name +
                            &quot; Under age, age is: &quot; + v0_Driver.age);
                            retract(v0_Driver);
                    }
                }
            }
        </rl-text>
    </rule-source>
    <ruleset-stack>
        <ruleset-name>vehicleRent</ruleset-name>
    </ruleset-stack>
</rule-execution-set>

E.2.2 Creating a Rule Execution Set from Oracle RL Text Specified in a URL

You can use JSR-94 with Oracle RL rulesets specified using a URL. For more information, see "Using the Extended createRuleExecutionSet to Create a Rule Execution Set" for information about JSR-94 extensions that assist you in specifying a URL.

To create a rule execution set from Oracle RL text specified in a URL:

1. Specify the Oracle RL mapping information in an XML document. Table E-2 shows the mapping elements required to construct a rule execution set. Example E-2 shows a sample XML document for mapping Oracle RL text to a JSR-94 rule execution set.

2. You then use the XML document with the JSR-94 administration APIs to create a rule execution set. The resulting rule execution set is registered with a JSR-94 runtime (using a RuleAdministration instance).

<?xml version="1.0" encoding="UTF-8"?>
<rule-execution-set xmlns="http://xmlns.oracle.com/rules/jsr94/configuration"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.0">
    <name>CarRentalDemo</name>
    <description>The Car Rental Demo</description>
    <rule-source>
        <rl-url>
            file:rl/DM.r1
        </rl-url>
    </rule-source>
    <rule-source>
        <rl-url>
            file:r1/VehicleRent.r1
        </rl-url>
    </rule-source>
    <ruleset-stack>
        <ruleset-name>vehicleRent</ruleset-name>
    </ruleset-stack>
</rule-execution-set>

E.2.3 Creating Rule Execution Sets with Rulesets from Multiple Sources

A rule execution set may contain rules that are derived from multiple sources and the sources may be a mix of Rules Designer defined rulesets and RL Language rulesets. In this case, the XML element <rule-execution-set> set contains multiple <rule-source> elements, one for each source of rules. You must list each <rule-source> in the order in which they are to be interpreted in Rules Engine.

E.3.1 Creating a Rule Execution Set with createRuleExecutionSet

The RuleExecutionSetProvider and LocalRuleExecutionSetProvider interfaces in javax.rules.admin include the createRuleExecutionSet to create a RuleExecutionSet object.

For the remaining createRuleExecutionSet methods, the first argument is interpreted as shown in Table E-3.

The second argument to the createRuleExecutionSet methods is a java.util.Map of vendor-specific properties.

E.3.2 Creating a Rule Session with createRuleSession

Clients create a JSR-94 rule session using the createRuleSession method in the RuleRuntime class. This method takes a java.util.Map argument of vendor-specific properties. This argument can be used to pass in any of the properties defined for the Oracle Business Rules oracle.rules.rl.RuleSession. If a rule execution set contains URL or repository rule sources, the rules from those sources are fetched on the creation of each new RuleSession.

E.3.3 Working with JSR-94 Metadata

JSR-94 allows for metadata for rule execution sets and rules within a rule execution set. The Oracle Business Rules implementation does not add any additional metadata beyond what is in the JSR-94 specification. The rule execution set description is an optional item and thus may not be present. If it is not present, the empty string is returned. For rules, only the rule name is available and the description is initialized with an empty string.

E.3.4 Using Oracle Business Rules JSR-94 Extensions

This section covers the following extensions provided in the JSR-94 implementation classes.

• Using the Extended createRuleExecutionSet to Create a Rule Execution Set

• Invoking an RL Language Function in JSR-94

RuleExecutionSet createRuleExecutionSet(String name,
                                        String description,
                                        RuleSource[] sources,
                                        String[] rulesetStack,
                                        Map properties)

import javax.rules.*;
...
StatefulRuleSession session;
...
((oracle.rules.jsr94.RLStatefulRuleSession) session).callFunction("myFunction");