Business processes cannot always proceed in a fully automated manner. They need human interaction as a means of decision making, error handling and exception cases. For example, canceling a flight due to a strike or bankruptcy, deciding whether to accept the claim based on the requested amount etc. Human tasks provide the specification to define tasks performed by human beings.
When a user requests a claim to be approved by the system, the system automatically approves claims under an amount of 1000 .This is a simple BPEL process. If the claim exceeds 1000, it will be handed over to the regional clerk who checks the claim amount along with the user information, decides whether or not to approve it, and the final decision is sent to the user. So when the claim is higher than 1000, it will be processed as a human task. The sample process is shown below.
Writing human tasks
The basic process is designed as a normal BPEL process with an IF component. For human tasks, we use the bpel4people activity remote task. It will get the input from the claim approval request such as the name and amount, and the output is sent via a claim approval callback service as true or false. The user can then see the final decision. This process needs some presentation elements. Task UI is implemented using JSP.
There is a predefined package structure which makes the work easier. As an initial step, you should create a package structure in your local directory.
This topic explains how to write the human tasks yourself and describes the various configurations you can use. You can view a completed version of the human tasks configuration in the
humantask directory and unzipping the .zip file. See here for information on how to set up and run this sample.
Package structure of an HT artifact
There are four components in the HT package.
The .ht file contains the information about the human task of the BPEL process. It is an XML-based file consisting of a predefined set of human task description elements. The table below shows the basic elements and their descriptions with some examples from the ClaimsApprovalTask sample.
|Contains declarations of elements from the WS- HumanTask namespace, that is |
This is used to import the appropriate WSDL files. You should correctly specify the name spaces.
This is used to specify logical people groups used in an inline human task or a people activity. The name attribute contains the name of the logical people group. The name must be unique among the names of all logical people groups defined within the
Specifies the human tasks used in the business process.
This is used to provide the definition of an inline human task. The name attribute specifies the name of the task. The name must be unique among the names of all tasks defined within the
It also consists of the
Specifies the port types and operations of the human task.
Used to assign people to process-related generic human roles.
Provides annotations for users.
From element used to assign people for roles which have been specified in the business process. Argument element will pass values used in the people query.
Specifies the user interface for human tasks or how the user interacts with the human task.
Used to provide the definition of an inline notification.The name attribute specifies the name of the notification. The name must be unique among the names of all notifications defined within the
This file consists of deployment details of the human task. Human tasks supports two task types called task and notification. A task can have a publish and a callback. Publish means providing a service and Callback means calling an external service to provide the output. Notification is also a task type. A notification task provides one operation for external parties to create notifications.
Example from the claim task sample:
Here, the htconfig.xml file consists of three services used by a human task; get data from the user, call back of either approve or not and the reminder web service.
You can have one or more WSDL files which have been used in the BPEL process. You can have a composite WSDL addressing many web services. Claim Approval task has one composite WSDL.
There are four .jsp files inside the web folder. Three .jsp files end with:
The input.jsp file uses the
(OMElement) request.getAttribute("taskInput") attribute to obtain the task details of the OMElement. This is inserted into the JSP context from BPS. The input.jsp file is used to show the task information to the task user.
Example from the ApproveClaim-input.jsp:
The input web will show the human task list of the regional clerk user.
The output .jsp is used to provide the user with a task form. Task processing happens when this is completed and submitted by the user.
This should provide the corresponding XML string expected by the task operation.
Example from the ApproveClaim-output.jsp:
Output JSP is used by the regional clerk user to approve the claim.
Response.jsp is used to display the output of the completed task. It also uses the OMElement responseElement = (OMElement) request.getAttribute("taskOutput"); to obtain the OMElement corresponding to the output.
Example from the ApproveClaim-response.jsp:
The response after approving the claim looks like this:
An additional .jsp called <TaskName>-Reminder-input.jsp exists to send reminders for task caller.
Tooling support for humantask is under development.