Using the Scope Element

The Scope activity is essentially a collection of child activities that can have their own Variables, Fault and Event Handlers, and correlation sets. The Scope activity provides the behavior context for the child elements. The attributes defined for a parent Scope have local visibility inside this Scope. For example, the variables declared for a Scope are visible only inside that Scope and all nested Scopes. These variables can then be used for the child activities of this Scope.

Usage

1. In the Design view, drag the Scope element from the Palette to the diagram.

2. Right-click the element and choose Add from the pop-up menu to add the following:

   • Variables

   • Using an Event Handler

   • Using a Fault Handler

3. In the Design view, drag elements from the Palette and place them inside the Scope element.

4. Configure the elements.

5. (Optional) Specify the name of the Scope element in the Properties window, invoked by right-clicking the element and choosing Properties.

Variables

Variables in BPEL programming function just as they do in other programming languages: they hold temporary values, form parts of expressions, or are passed as parameters to external partners. Normally, you need a variable for every message sent to or received from a partner service. The BPEL Designer supports the following types of variables:

• WSDL Message type. These variables correspond to web service message types that are defined in WSDL files imported by the process. In a BPEL file ( .bpel), these variables must specify a value for the messageType attribute. Message type variables are used to hold data in interactions between the process and its partner services.

• XML Schema type. These variables correspond to simple or complex XML Schema data types. The XML schema types themselves are defined in XML Schema files (.xsd) or in WSDL files that are imported into the process. In a BPEL file, variables of this type must specify a value for the type attribute.

• XML Schema element. These variables correspond to XML Schema elements.The XML schema elements themselves are defined in XML Schema files (.xsd) or in WSDL files that are imported into the process. In a BPEL file, variables of this type must specify a value for the element attribute.

• Built-in type. Variables of this type are standard simple types defined in the XML Schema specification.

Global and Local Variables

The variables defined at the Process root are global variables, which have a global visibility throughout the entire process. The variables defined within a particular Scope are visible only inside that Scope and all nested Scopes. These variables are called local variables. A variable defined for an inner Scope element can hide an upper defined variable of the same name.

The name of a variable must be unique among the names of all variables defined within the same Scope.

To define a variable:

1. Right-click the Process or Scope element and select Add > Variable.

2. In the Create New Variable dialog box, name the variable. The name should be unique within this Scope element.

3. Expand the node corresponding to the type of the new variable and select its type. You have the following options:

   • Built-in Types. Expand the Built-in Types node, select the type's name, and click OK.

   • Message Type. Expand a .wsdl file node, select a message type and click OK.

   • XML Schema. Expand an .xsd file node or a .wsdl file that contains an embedded schema. Expand the Global Complex Type, Global Simple Type, or Global Elements Simple nodes, select the appropriate type, and click OK.

     For your convenience, global types of variables are displayed in bold.

4. (Optional) Clear the Show Imported Files Only checkbox to view the contents of non-imported WSDL and XML schema files.

5. Click OK.

   By default, the Create New Variable dialog box only shows those files that have already been referenced in the process. However, the project may contain other WSDL and XSD files which have not yet been imported into the process. If you select a type for the new variable that is defined in a non-imported file, the IDE will automatically add the required import to the BPEL process.

   You can also add variables from the The Navigator Window window. To add a variable, select BPEL Logical View in the Navigator, expand your BPEL Module project's node, right-click the Variables node and choose Add Variable.

To edit a variable:

1. In the Navigator window, select BPEL Logical View.

2. Expand BPEL Module project's node > Variables and double-click the variable you want to edit.

3. In the Property Editor dialog box for the variable, change the variable type and name.

4. Click OK.