Walkthrough: Invoking the Policy from an Orchestration

You can invoke a policy from an orchestration in one of the following ways:

• By using the Call Rules shape

• By using the Expression shape, and programmatically invoking the rule engine to execute the policy (Policy.Execute method)

  Using the Call Rules shape is the most common way and also the recommended way to invoke a policy from an orchestration. This walkthrough provides step-by-step procedures for using the Call Rules shape to invoke the ProcessPurchaseOrder policy.

Prerequisites

You must complete the Walkthrough: Testing the Policy walkthrough before performing this walkthrough.

Overview of This Walkthrough

This walkthrough contains seven procedures, as described in the following table.

To create a BizTalk project with a schema and an orchestration

1. Start Microsoft Visual Studio.

2. In Visual Studio, on the File menu, point to New, and then click Project.

3. In the New Project dialog box, do the following:

   Use this	To do this
   Project types	Click BizTalk Projects.
   Templates	Click Empty BizTalk Server Project.
   Name	Type RuleTest.
   Location	Specify C:\BRE-Walkthroughs.
   Solution Name	Type RuleTestSol.
   Create directory for solution	Select this check box to create a directory for the solution files.

4. Click OK. The RuleTest project should appear in Solution Explorer. If you do not see Solution Explorer, click Solution Explorer on the View menu.

5. In Solution Explorer, right-click RuleTest, point to Add, and then click Existing Item.

6. Browse and add the PO.xsd schema file you created in the Walkthrough: Creating a Simple Business Policy walkthrough. Visual Studio makes a copy of the PO.xsd file and adds it to the project.

7. In Solution Explorer, right-click RuleTest, point to Add, and then click New Item.

8. In the Add New Item dialog box, do the following:

   Use this	To do this
   Categories	Click Orchestration Files.
   Templates	Click BizTalk Orchestration.
   Name	Type RuleTest.odx.

9. Click Add.

10. Right-click Drop a shape from the toolbox here, point to Insert Shape, and then click Receive.

11. In the Properties window, change the name of the Receive shape to ReceivePO, and set the value of the Activate property to true.

12. In the Toolbox, on the BizTalk Orchestrations tab, drag the Call Rules shape onto a connecting line below the Receive shape.

13. In the Properties window, change the name of the Call Rules shape to CallProcessPOPolicy.

14. Right-click below the Call Rules shape, point to Insert Shape, and then click Send.

15. In the Properties window, change the name of the Send shape to SendPO. The orchestration should look like the following figure.

    

To create message variables

1. In the Orchestration View window, right-click Messages, and then click New Message. If you do not see the Orchestration View window, click the View menu, point to Other Windows, and then click Orchestration View. Typically, the Orchestration View window is on the tab next to the Solution Explorer tab. By default, the new message is named Message_1.

   

2. In the Orchestration View window, click Message_1.

3. In the Properties window, do the following:

   Use this	To do this
   Identifier	Type POInst, and then press ENTER.
   Message Type	From the drop-down list, expand Schemas, and then select RuleTest.PO.

   

To configure shapes

1. Select the Receive shape in Orchestration Designer.

2. In the Properties window, select POInst for the Message property.

3. Double-click the Call Rules shape in Orchestration Designer.

4. In the Call Rules policy configuration dialog box, select ProcessPurchaseOrder for the policy.

5. Click next to \, below **Parameter Name, and select *POInst as a parameter to the policy.

   

6. Click OK.

7. Select the Send shape in the orchestration.

8. In the Properties window, set the value of the Message Type property to POInst.

To create ports

1. Create two folders, Input and Output, in the C:\BRE-Walkthroughs\RuleTestSol folder.

2. Right-click the left port surface of the orchestration, and then click New Configured Port.

3. Click Next. Type ReceivePOPrt for the port name.

4. Click Next twice.

5. Select Specify Now for the port binding.

6. Specify FILE for the transport, and type the name of the input directory as C:\BRE-Walkthroughs\RuleTestSol\Input\*.xml along with the file mask (*.xml) for the URI.

7. Click Next, and then click Finish.

8. Right-click the right port surface of the orchestration, and then click New Configuration Port.

9. Click Next. Type SendPOPort for the port name.

10. Click Next twice.

11. Change the Port direction of communication to I'll always be sending messages on this port.

12. Select Specify Now for the port binding.

13. Specify FILE for the transport, and type the name of the output directory as C:\BRE-Walkthroughs\RuleTestSol\Output,and %MessageID%.xml as the output file name.

14. Click Next, and then click Finish.

To connect ports with the shapes

1. Connect the ReceivePOPrt port to the ReceivePO shape. (Drag the arrow to the right of ReceivePOPrt port on the port surface to the box on the ReceivePO shape.)

   

2. Connect the SendPO shape to the SendPOPrt port.

   

To build and deploy the solution

1. Start Microsoft Visual Studio.

2. In Visual Studio, in Solution Explorer, right-click the RuleTest project, and then click Properties.

3. In Project Designer (in the center pane), click Signing.

4. In Signing tab, Check Sign the assembly checkbox; In the dropdown list Choose a strong name key file, click New; In the Key File name field, enter Rule Test; In the Password field (Optional), set Password, and then click OK.

5. In Project Designer, click Deployment to switch to the Deployment tab.

6. Specify RuleTestApp as the application name.

   

7. Click OK.

8. Right-click the RuleTest project, and then click Build.

9. Right-click the RuleTest project, and then click Deploy.

To test the solution

1. In Business Rule Composer, expand Policies, expand ProcessPurchaseOrder, right-click Version 1.0, and then click Publish.

2. Right-click Version 1.0 - Published, and then click Deploy.

3. In the Start menu, open BizTalk Server Administration. If you have the BizTalk Server Administration console already open, press F5 to refresh it.

4. Expand Console Root, expand BizTalk Server Administration, expand BizTalk Group, and then expand Applications.

5. Right-click RuleTestApp, and then click Configure.

6. Click Orchestration_1, and specify BizTalkServerApplication as the host.

   

7. Click OK.

8. Right-click RuleTestApp, and then click Start.

9. In the Start 'RuleTestApp' Application dialog box, click Start, and then wait until the application is started successfully.

10. Open SamplePO.xml and SamplePO2.xml in Notepad and change the value of the Status field to XYZ.

11. Copy the SamplePO.xml file from the C:\BRE-Walkthroughs directory to the C:\BRE-Walkthroughs\RuleTestSol\Input directory for the orchestration.

12. You should see an output file in the C:\BRE-Walkthroughs\RuleTestSol\Output directory for the orchestration. Open the output XML file and notice that the value of the Status field is set to Approved.

13. Repeat steps 11 and 12 with SamplePO2.xml, and notice that the value of the Status field in the output document is the same as in the input document (xyz).

Comments

• In this walkthrough, to add the shapes to the orchestration, you did not use the shapes from the Toolbox. Instead, you clicked the right mouse button and selected the shape that you wanted to insert.

• The configuration for the Call Rules shape looks at the latest saved version when determining the types used. At run time, the latest deployed version will be used.

• If you plan to use a policy version other than the latest deployed version, you should use an Expression shape, and invoke the rule engine programmatically to execute the policy of that specific version. For more information, see How to Execute Policies.

• The Call Rules shape reconstructs the message, as if using a Construct Message shape, which in turn may cause context properties of the message to be lost.

• A policy cannot be modified after it is published.

• The client applications can access only the deployed policies. If a client application invokes a policy that is not deployed, the rule engine generates a RuleEngineDeploymentNotDeployedException exception. You can see the detailed error message in the application event log.

Next Steps

Now that you have completed this walkthrough, perform the Walkthrough: Creating and Using a Vocabulary in the Policy walkthrough, which gives you step-by-step instructions for creating a vocabulary and using the vocabulary in the ProcessPurchaseOrder policy.

See Also

Condition Evaluation and Action Execution
Agenda and Priority
Invoking Business Rules in Orchestrations