Example 10: Modify a parameter value in a template in a rule set

package com.ibm.websphere.sample.brules.mgmt;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import com.ibm.wbiserver.brules.mgmt.BusinessRuleGroup;
import com.ibm.wbiserver.brules.mgmt.BusinessRuleManagementException;
import com.ibm.wbiserver.brules.mgmt.BusinessRuleManager;
import com.ibm.wbiserver.brules.mgmt.Operation;
import com.ibm.wbiserver.brules.mgmt.ParameterValue;
import com.ibm.wbiserver.brules.mgmt.query.QueryOperator;
import com.ibm.wbiserver.brules.mgmt.ruleset.RuleSet;
import com.ibm.wbiserver.brules.mgmt.ruleset.RuleSetRule;
import
com.ibm.wbiserver.brules.mgmt.ruleset.RuleSetTemplateInstanceRule;
import com.ibm.wbiserver.brules.mgmt.BusinessRule;
import com.ibm.wbiserver.brules.mgmt.ruleset.RuleBlock;

public class Example10
{
static Formatter out = new Formatter();

static public String executeExample10()
{
		try
		{
				out.clear();
				
				// Retrieve a business rule group by target namespace and
				name
				List<BusinessRuleGroup> brgList = BusinessRuleManager
						.getBRGsByTNSAndName(
								"http://BRSamples/com/ibm/websphere
								/sample/brules",
								QueryOperator.EQUAL,
								"ApprovalValues",
								QueryOperator.EQUAL, 0, 0);
				if (brgList.size() > 0)
				{
						// Get the first business rule group from the list
						// This should be the only business rule group in the
						list as
						// the combination of target namespace and name are
						unique
						BusinessRuleGroup brg = brgList.get(0);
						// Get the operation of the business rule group that
						// has the business rule that will be modified as
						// the business rules are associated with a specific
						// operation
						Operation op = brg.getOperation("getApprover");
						
						// Get the business rule on the operation that will
						be modified
						List<BusinessRule> ruleList =
						op.getBusinessRulesByName(
								"getApprover", QueryOperator.EQUAL, 0,
								0);

						if (ruleList.size() > 0)
						{
								out.println("");
								out.printlnBold("Rule set before publish:");
								// Get the rule to be modified. Rules are
								unique by
								// target namespace and name, but for this
								example
								// there is only one business rule named
								"getApprover"
								RuleSet ruleSet = (RuleSet) ruleList.get(0);
								out.print(RuleArtifactUtility.printRuleSet(rule
								Set));

All of the rules in a rule set are in a rule block. Only one rule block is supported and the getFirstRuleBlock method should be used to retrieve the rule block.

						// A rule set has all of the rules defined in a
						rule block
						RuleBlock ruleBlock =
						ruleSet.getFirstRuleBlock();

						Iterator<RuleSetRule> ruleIterator =
						ruleBlock.iterator();

						// Iterate through the rules in the rule block
						to find the
						// rule instance called "LargeOrderApprover"
						while (ruleIterator.hasNext())
						{
								RuleSetRule rule = ruleIterator.next();

If a rule is not defined with a rule template, it only has a web presentation that can be retrieved. No updates can be made to a rule that is not defined with a template. It is best to check if a rule has been defined with a template if the name of the rule is unknown.

						// The rule must have been defined with a
						template
						// in order for it to be changed. Check
						if the current
						// rule is even based on a template.
						if (rule instanceof
						RuleSetTemplateInstanceRule)
						{

Use the TemplateInstance object to create the rule.

								// Get the rule template instance
								RuleSetTemplateInstanceRule
								templateInstance =
								(RuleSetTemplateInstanceRule) rule;

								// Check for the rule instance
								which matches
								// the rule to modify
								if
								(templateInstance.getName().equals(
										"LargeOrderApprover"))
								{

For the template instance, only parameter values can be modified. The parameters are modified by retrieving the ParameterValue and setting it to the appropriate value. Because the ParameterValue is passed by reference, the update is made directly on the rule, rule set, and business rule group.

										// Get the parameter from the
										rule instance
										ParameterValue parameter =
										templateInstance
												.getParameterValue("par
												am2");

										// Modify the value of the
										parameter
										parameter.setValue("superviso
										r");
										break;
								}
				 		}
				}
				// Use the original list or create a new list
				// of business rule groups
				List<BusinessRuleGroup> publishList = new
				ArrayList<BusinessRuleGroup>();

				// Add the changed business rule group to the list
				publishList.add(brg);

				// Publish the list with the updated business rule
					group
					BusinessRuleManager.publish(publishList, true);

				out.println("");
				// Retrieve the business rule groups again to verify
				the
				// changes were published
				out.printlnBold("Rule set after publish:");

				brgList = BusinessRuleManager
						.getBRGsByTNSAndName(
								"http://BRSamples/com/ibm/websphere/sample/brules",
								QueryOperator.EQUAL, "ApprovalValues",
								QueryOperator.EQUAL, 0, 0);

				brg = brgList.get(0);
				op = brg.getOperation("getApprover");
				ruleList = op.getBusinessRulesByName(
						"getApprover", QueryOperator.EQUAL, 0,0);

				ruleSet = (RuleSet) ruleList.get(0);
				out.print(RuleArtifactUtility.printRuleSet(ruleSet));
				}
		}
		} catch (BusinessRuleManagementException e)
		{
				e.printStackTrace();
				out.println(e.getMessage());
		}
		return out.toString();
		}
}

Executing example10

Rule set before publish:
Rule Set
Name: getApprover
Namespace: http://BRSamples/com/ibm/websphere/sample/brules
Rule: LargeOrderApprover
Display Name: LargeOrderApprover
Description: null
Expanded User Presentation: If the number of items order is above 10 and 
the order is above $5000, then it requires the approval of manager
User Presentation: If the number of items order is above {0} and 
the order is above ${1}, then it requires the approval of {2}
Parameter Name: param0
Parameter Value: 10
Parameter Name: param1
Parameter Value: 5000
Parameter Name: param2
Parameter Value: manager
Rule: DefaultApprover
Display Name: DefaultApprover
Description: null
Expanded User Presentation: approver = peer
User Presentation: approver = {0}
Parameter Name: param0
Parameter Value: peer

Rule set after publish:
Rule Set
Name: getApprover
Namespace: http://BRSamples/com/ibm/websphere/sample/brules
Rule: LargeOrderApprover
Display Name: LargeOrderApprover
Description: null
Expanded User Presentation: If the number of items order is above 10 and 
the order is above $5000, then it requires the approval of supervisor
User Presentation: If the number of items order is above {0} and the order 
is above ${1}, then it requires the approval of {2}
Parameter Name: param0
Parameter Value: 10
Parameter Name: param1
Parameter Value: 5000
Parameter Name: param2
Parameter Value: supervisor
Rule: DefaultApprover
Display Name: DefaultApprover
Description: null
Expanded User Presentation: approver = peer
User Presentation: approver = {0}
Parameter Name: param0
Parameter Value: peer