Using assign

Use the assign activity to manipulate data within your BPEL process and map data from one location to another.

1. From the palette, drop an assign activity onto the canvas.
2. Click the Details tab in the properties area. You will now see a table that has one column labelled Assign From, and another labelled Assign To. Quite simply the value in the left column is assigned into the location specified in the column on the right.
3. Click Add to create a new row, or Remove to delete an existing one. You can change the order of the rows with the Up and Down buttons.
   Note:

   • The order shown here represents the sequence in which the copies will be executed in the runtime environment, so variables must be initialized accordingly. For example, the second copy cannot use a variable that is initialized by third copy.
   • When an existing assignment can be modified, the Edit Query icon () will appear in the cell. Click this icon to make the necessary changes.
4. In the Assign From column, click Select From. A content assist dialogue will appear with the following options:

   Option	Description
   Input	Choose this to select a variable.
   Date	Use the interactive calender display to choose a date.
   String	Enter an appropriate textual value.
   Number	Enter an appropriate numeric value.
   Boolean	Choose either True or False from the dialogue.
   XPath Expression	This choice will launch the XPath Expression Builder that you can use to visually compose an appropriate XPath expression.
   XML Literal	Enter the appropriate well-formed XML code. Note: An XM Literal builder is provided to allow you to easily generate XML code using a simple interface. Also note that you must set the Assign To value before defining the Assign From as an XML Literal.
   Property of a variable	Choose this to select an appropriate property from an existing variable.
   Partner reference	Choose this to select a partner.
   Endpoint Reference	This choice will launch the Select Endpoint Reference window. Use it to specify an existing interface with an endpoint, or specify the URI explicitly.

5. In the Assign To column, click Select To. A content assist dialogue will appear with options that are appropriate to the to the choice made in the Assign From column. Choose something appropriate.

Example: using arrays in assign and forEach activities

This example will demonstrate how you can use an assign activity to iterate an array within a forEach activity (you can also go to WS-BPEL 2.0 forEach activity - a typical usage pattern for another example).

1. Create a business object called MyBO with an element called array of type string, and with the property of array.
2. Create a new BPEL process, and have the interface generated automatically.
3. Create a new variable called VarArray in your BPEL process that calls MyBO.
4. Drop an assign activity between the existing Receive and Reply activities, and create three values as follows:
   1. In the Assign from field, open the code assist, select String (enter a value), and type test 01.
   2. In the corresponding Assign To field, select VarArray : MyBO > array : Array of string. The value VarArray array[1] appears in the field.
   3. Click Add to create a new field in the assign activity.
   4. Repeat these steps twice more, increasing the numeric value each time so that it matches the following screen capture:
      
      Note: You will not be able to edit the Assign To value directly. To make changes to array [1], click the Edit Query icon (, and make changes to the field in the XPath Expression Builder window.
5. Drop a forEach activity below the assign activity, and configure it as follows:
   1. In the Details tab, under the Iteration heading, click none in the Type field, and select Array (dynamic bounds) > varArray : MyBO > array : Array of string.
   2. Drop an assign activity into the forEach activity.
   3. In the Assign from field, select varArray : MyBO > array : Array of string.
   4. Modify the automatically generated VarArray array[1] to be VarArray array[bpws:getVariableData('Index')].
   5. In the corresponding Assign To field, select Input 1: string.
   6. Drop a snippet activity below the assign activity, and add the following code to it: System.out.println( "In ForEach: " + Input1 );.

Your completed BPEL process will look like this: