To start, double-click on the Bookstore composite in our existing project tree. This will open the SOA composite view, which shows the main building blocks (service components) of our application. So far, we have a BPEL process named BookstoreABPEL, which is exposed as SOAP web service through a WSDL interface.

Add a second BPEL process named BookstoreBBPEL. To achieve this, drag-and-drop the BPEL Process component from the right-hand side toolbar to the Components space of the SOA composite:

Doing this will add the BPEL process component and immediately open the dialog box, where we need to specify the BPEL process name and other details, such as the BPEL version, XML namespace, select the process template, and define the service name. Again, use the BPEL 2.0 specification, name the process BookstoreBBPEL, select the namespace from the packtpub.com domain, and select the Synchronous BPEL Process template, as shown on the following screenshot:

After clicking on OK, we will see the composite with the added BPEL process. On the left-hand side in the project tree, we can see that several artifacts have been generated, including the WSDL interface and the corresponding XSD (XML Schema).

We are now ready to implement the process. To do so, double-click on the BookstoreBBPEL component represented by the blue rectangle. This will open the BPEL design perspective.

Use the same schemas as in the BookstoreABPEL process. To achieve this, we can edit the WSDL file of the BookstoreBBPEL process named BookstoreB.wsdl. Let's double-click on the file, click on the source tab, and modify the import of the schema. Instead of using the BookstoreBBPEL.xsd file, use the BookstoreBPEL.xsd. We also need to modify the XML namespace under the client namespace alias:

We also need to modify WSDL a little bit. We basically need to do the same changes as we did earlier in this chapter for the BookstoreABPEL process. To summarize, rename the operation name from process to getBookData. Modify both message elements to BookData and BookDataResponse respectively, and modify the schema location to use the BookstoreBPEL.xsd file:

Let's now go back to the BookstoreBBPEL process design window tab. In contrast to the first example, we will hardcode the response for a few predefined book ISSNs for which the BPEL process will return different stock quantities. For the 1111-1111 ISSN, it will return 10 books; for the 2222-2222 ISSN, it will return 20 books; for the 3333-3333 ISSN, it will return 30 books. For all other ISSNs, we will return five books.

First, add the <if> activity to the BPEL process by dragging-and-dropping the If icon from the lower-right side of the toolbar (look under Structured Activities). Drop the <if> activity between the receiveInput and replyOutput activities.

As we have four choices that we need to cover, first add the two Else If branches. Click on the <if> activity so that a big green plus sign will appear. Clicking on it will reveal Else If:

Let's now click on the Else If branch twice. Next, we need to add expressions, which will serve as the conditions for the if and elseif branches. Let's click on the first label. Name it ISSN1.

Next, right-click on the first if and select Edit. We could enter the condition directly, but will use the Expression Builder instead. Let's click on the Fx icon, to start Expression Builder.

In Expression Builder, use the equals operator to compare strings. Compare the ISSN within the inputVariable payload and compare it with the '1111-1111' string:

After clicking on OK, we will see the expression in the initial Edit If dialog box:

Enter other two conditions in the same way, first for the 2222-2222 ISSN, and 3333-3333 ISSN.

For each <if> branch, we now have to add the corresponding <assign> activity, which will set the stock quantity output variable. We already know how to use the <assign> activity, as we have used it in the previous example. However, this time, set the stock quantity within the <if> activity only. Set the other parameter, the BookISSN in the output variable after the <if> activity, as it is the same for all if branches.

First, let's add the <assign> by dragging-and-dropping the activity from the right-hand toolbar. It will appear as Assign1. Let's double-click on the Assign1 activity and create a copy rule, where we will copy the number 10 to the stock quantity:

Let's now rename the Assign1 activity to a more meaningful name. We can do this under the General tab, as shown in the following screenshot:

Add the other three <assign> activities to the BPEL process the same way. The first activity will assign the quantity of 20, the second 30, and the last (under the else branch) the quantity of 5.

Let's now add the final assign that will copy the BookISSN from the input variable to the output variable. Add the assign after the <if> activity and before the replyOutput activity:

The assign will copy BookISSN from inputVariable to BookISSN of outputVariable. Please note that it would be the same if this assign activity would be added after the receive activity and before the if activity, as shown in the following screenshot: