Writing a Human Task Artifact

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.

Sample scenario

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.

Package structure of an HT artifact

There are four components in the HT package.

.ht file

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.

<htd:humanInteractions>

<htd:import>

<htd:import namespace="http://reminder.sample.humantask.wso2.org" location="OrderProcessReminder.wsdl" importType="http://schemas.xmlsoap.org/wsdl/">

<htd:logicalPeopleGroups>

<htd:logicalPeopleGroups>

        <htd:logicalPeopleGroup name="regionalClerks">
            <htd:documentation xml:lang="en-US">
                The group of clerks responsible for the region specified.
            </htd:documentation>
            <htd:parameter name="role" type="xsd:string"/>
        </htd:logicalPeopleGroup>

        <htd:logicalPeopleGroup name="regionalManager">
            <htd:documentation xml:lang="en-US">
                The manager responsible for the region specified.
            </htd:documentation>
            <htd:parameter name="role" type="xsd:string"/>
        </htd:logicalPeopleGroup>

        <htd:logicalPeopleGroup name="clerksManager">
            <htd:documentation xml:lang="en-US">
                The manager of the clerk whose user ID is passed as parameter.
            </htd:documentation>
            <htd:parameter name="role" type="xsd:string"/>
        </htd:logicalPeopleGroup>

        <htd:logicalPeopleGroup name="directorClaims">
            <htd:documentation xml:lang="en-US">
                The functional director responsible for claims processing.
            </htd:documentation>
        </htd:logicalPeopleGroup>

</htd:logicalPeopleGroups>
 
<htd:logicalPeopleGroups>
       <htd:logicalPeopleGroup name="regionalClerks">
           <htd:documentation xml:lang="en-US">
               The group of clerks responsible for the region specified.
           </htd:documentation>
           <htd:parameter name="role" type="xsd:string"/>
       </htd:logicalPeopleGroup>


	   <htd:logicalPeopleGroup>
    	.....
	   </htd:logicalPeopleGroup>
</htd:logicalPeopleGroups>

<htd:tasks>

<htd:tasks>
        <htd:task1>
        <htd:task2>
        <htd:task3>
<htd:tasks>

<htd:task>

<htd:task name="OrderProcess">  
	<htd:interface />
	<htd:peopleAssignments />
	<htd:presentationElements/>
</htd:task>

<htd:interface>

<htd:interface 
 portType="cl:ClaimsHandlingPT"  
  operation="approve"   
 responsePortType="cl:ClaimsHandlingCallbackPT"   
  responseOperation="approvalResponse"/>  

<htd:peopleAssignments>

<htd:peopleAssignments>
	<htd:potentialOwners>
		<htd:from logicalPeopleGroup="regionalClerks">
			<htd:argument name="role">
				regionalClerksRole
			</htd:argument>
		</htd:from>
	</htd:potentialOwners>
	<htd:businessAdministrators>
		<htd:from logicalPeopleGroup="regionalManager">
			<htd:argument name="role">
				regionalManagerRole
			</htd:argument>
		</htd:from>
	</htd:businessAdministrators>
</htd:peopleAssignments>

<htd:documentation>

<htd:documentation>   
	Example for WS-HumanTask 1.1 - WS-HumanTask Task Definition  
</htd:documentation> 

<htd:from>
<htd:argument> 

<htd:from logicalPeopleGroup="regionalClerks">
 	<htd:argument name="role">
		regionalClerksRole
	</htd:argument>
</htd:from>

<htd:presentationElements>

<htd:presentationElements>   
<htd:name xml:lang="en-US">Approve Claim
</htd:name>  
<htd:name xml:lang="de-DE">Genehmigungder Schadensforderung  
</htd:name>   
<htd:presentationParameters>   
<htd:presentationParametername="firstname"  
  type="xsd:string">   
 htd:getInput("ClaimApprovalRequest")/test10:cust/test10:firstname   
</htd:presentationParameter>   
</htd:presentationParameters>

<htd:notifications>

<htd:notifications>   
  <htd:notificationname="ClaimApprovalReminder">  
  	<htd:documentationxml:lang="en-US">

htconfig.xml file

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:

<hic:HTDeploymentConfig xmlns:hic="http://wso2.org/ht/schema/deployment/config"
	xmlns:claim="http://www.example.com/claims/"
	xmlns:claimtask="http://www.example.com">
	<hic:task name="claimtask:ApproveClaim">
		<hic:publish>
			<hic:service name="claim:ClaimService" port="ClaimPort"/>
		</hic:publish>
		<hic:callback>
			<hic:service name="claim:ClaimServiceCB" port="ClaimPortCB"/>
		</hic:callback>
	</hic:task>
	<hic:notification name="claimtask:ClaimApprovalReminder">
		<hic:publish>
			<hic:service name="claim:ClaimReminderService" port="ClaimReminderPort"/>
		</hic:publish>
	</hic:notification>
</hic:HTDeploymentConfig>

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.

<Service>.wsdl

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.

Web folder

There are four .jsp files inside the web folder. Three .jsp files end with:

1. <TaskName>-input.jsp 
2. <TaskName>-output.jsp
3. <TaskName>-response.jsp

<TaskName>-input.jsp

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:

OMElement requestElement = (OMElement) request.getAttribute("taskInput");
	String ns = "http://www.example.com/claims/schema";
	if (requestElement != null) {
	OMElement customerElement = requestElement.getFirstChildWithName(new QName(ns, "cust"));
	if (customerElement != null) {
OMElement id = customerElement.getFirstChildWithName(new QName(ns, "id"));
if (id != null) {
customerId = id.getText();
}

The input web will show the human task list of the regional clerk user.

<TaskName>-output.jsp

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.

All output .jsp files should implement the JavaScript method:

createTaskOutput = function() { 
};

This should provide the corresponding XML string expected by the task operation.

Example from the ApproveClaim-output.jsp:

createTaskOutput = function() {
    var outputVal = getCheckedRadio(); //get approve or not from radio button
    if (outputVal == 'approve') {
        return '<sch:ClaimApprovalResponse xmlns:sch="http://www.example.com/claims/schema"><sch:approved>true</sch:approved></sch:ClaimApprovalResponse>';
    } else if (outputVal == 'disapprove') {
        return '<sch:ClaimApprovalResponse 	  
        xmlns: sch = "http://www.example.com/claims/schema" > < sch: approved > false < /sch:approved> <
            /sch:ClaimApprovalResponse>';
    }
};

Output JSP is used by the regional clerk user to approve the claim.

<TaskName>-response.jsp

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:

String approved = "No Value Assigned"; 
OMElement responseElement = (OMElement) request.getAttribute("taskOutput"); 
if (responseElement != null) { 
approved = responseElement.getFirstElement().getText(); }

The response after approving the claim looks like this: