ActiveVOS Designer User’s Guide

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Declaring Extension Elements and Attributes

The WS-BPEL 2.0 specification allows for extensions to the basic BPEL language in several ways, including extension elements and extension attributes for BPEL constructs.

For example, if you open a process containing elements and attributes that are not defined in the specification, the appropriate extension details are preserved by ActiveVOS Designer.

If the extension details include a Must Understand attribute set to Yes, you cannot simulate or remote debug your process, since ActiveVOS does not understand how to execute the process. In this case, ActiveVOS Designer declares an unknown extension as an error.

If the Must Understand attribute is set to No, the extensions are ignored when you simulate and debug your process.

You can add extension elements and attributes to any WS-BPEL 2.0 process; however, if you enable the Must Understand attribute, you will not be able to simulate or deploy the process to an ActiveVOS server.

To add or modify an extension attribute:

1. From the Outline view, s elect the BPEL construct that uses an extension attribute. Note that almost every construct, including the process element, partner links, activities, correlation sets, fault and event handlers, contain the Extension Attributes property in the Properties view.
2. In the Properties view, select the Show Advanced Properties button in the toolbar to display all properties.
3. Select the Dialog (...) Button at the end of the Extension Attributes row.
4. If your imported process contains extension attributes, they are displayed in the Extension Attributes dialog. Do one of the following:
• Select an attribute from the list and select Edit.
• Select Add to create a new attribute.
5. In the Extension Attribute dialog, do the following:
• Type in a Namespace or select from a list of existing extension namespaces.
• Add or edit the attribute Name.
• Add or edit the attribute Value.
• Select the Declare this extension check box if the extension namespace is new.
• Select the Must Understand check box if a BPEL engine must be able to understand the attribute value in order to correctly execute the process. Note that the ActiveVOS engine is not able to understand the attribute definition or value, and you will not be able to simulate or deploy the process to an ActiveVOS server.

The following illustration shows an example.



6. Click OK, and notice that the attribute is listed in the Extension Attributes dialog where you can edit and remove attributes from the list.

Tips:

• After you add an extension attribute, ActiveVOS adds a prefix for the namespace. If desired, select Namespaces from the Outline view and rename the prefix to something more meaningful.
• The Extension Attributes are displayed in the Properties view of the BPEL construct, in the order they were created.
• To reset the Must Understand attribute, select the Extensions namespace declaration from the Outline view and change the value in the Properties view

To add or modify an extension element:

1. From the Process Editor or Outline view, select the BPEL construct that uses an extension element. Note that almost every construct, including the process element, partner links, activities, correlation sets, fault and event handlers, contain the Extension Elements property in the Properties view.
2. In the Properties view, select the Show Advanced Properties button in the toolbar to display all properties.
3. Select the Dialog (...) Button at the end of the Extension Elements row.
4. If your imported process contains extension elements, they are displayed in the Extension Elements dialog. Do one of the following:
• Select an element from the list and select Edit.
• Select Add to create a new element.
5. In the Extension Element dialog, do the following:
• Type in fully qualified valid XML syntax in the Element text box. ActiveVOS validates the XML before enabling the OK button.
• Select the Declare this extension check box if the extension namespace is new.
• Select the Must Understand check box if a BPEL engine must be able to understand the element value in order to correctly execute the process. Note that the ActiveVOS engine is not able to understand the element definition or value, and you will not be able to simulate or deploy the process to an ActiveVOS server.

The following illustration shows an example.



6. Click OK, and notice that the element is listed in the Extension Elements dialog where you can reorganize the list and remove elements from the list.

Tips:

• Reorganize the extension element entries to reflect the order in which they should be executed
• To reset the Must Understand attribute, select the Extensions namespace declaration from the Outline view and change the value in the Properties view

Copyright (c) 2004-2010 Active Endpoints, Inc.