IBM Integration Designer Interview Questions II

What is difference between the parallel flow and generalized flow activities in BPEL process?

Parallel Flow

• A parallel process (or flow) is a collection of other process activities that are all nested within a parallel activity.
• The nested activities run sequentially in an order that is dictated by links and transition conditions (when no links are present, all activities will be executed concurrently).
• Parallel activities are very versatile, and can add a depth to a long-running process.

Generalized Flow

• A generalized flow activity is very similar to a parallel activity in that you can nest other process activities within it, and then control the execution order of those activities through links.
• The generalized flow activity differs in its ability to use conditional links to loop back to previous activities in the sequence.

How do you assign people to a process (people assignment)? What are the pre-defined roles for human tasks?

When you define a human task you must stipulate which people are eligible to view, initiate, perform and administer the task. This step is known as people assignment. You can assign work to a named individual, to a member of a certain group. There are pre-defined roles for human tasks which you can assign people or groups to. Members of a role share the same level of authority. The roles are:

Administrators - have the authority to perform high level duties like suspend, terminate, restart, force-retry, and force-complete.

Potential creators - can create an instance of the human task, but cannot start it.

Potential starters - have the authority to initiate an existing instance. The starter role is subtly different from that of creator, and although a creator can create a new instance, only a starter can start it.

Potential owners - can claim, work on and complete tasks.

Editors - can work with the content of a task, but cannot claim or complete it. For example, an editor can receive the work item to review a document and add comments, but an editor is not able to finish the task.

Readers - are allowed to view tasks, but cannot work on them. This role can be used in situations where someone needs to monitor a task without taking any action in it.

When do you decide to create a new version of BPEL process?

Here are some possible examples of when you would create a version of a BPEL process:

• In the likelihood that your BPEL process will need to be modified over time, but its callers will not. In such a case, you will want the existing callers to be able to seamlessly pickup the newest version of the process the moment it becomes effective.
• You have a solution where multiple versions of the same BPEL process must coexist. Although the solution as a whole cannot be uninstalled and reinstalled, you will need to be able to deploy new versions of the process in such a way as to ensure that new instances use the latest version and, wherever possible, existing instances also migrate to the latest version.

How do you handle faults or exceptions in BPEL process?

A fault is any exceptional condition that can change the normal processing of a BPEL process and, if not handled, can lead to undesirable conditions or results. A well-designed process is one that anticipates possible faults with fault handlers that are designed to lead to predictable outcomes.

What is Correlation or Correlation Sets? What is purpose of them?

• Correlations are used in runtime environments where there are multiple instances of the same process running.
• A correlation set for a BPEL process consists of a name and one or more properties. They are used to distinguish the instances of same process in runtime.
• Correlation sets allow two partners to initialize a BPEL process transaction, temporarily suspend activity, and then recognize each other again when that transaction resumes.

What are the transactional behavior options for the activities inside a BPEL process?

Commit before: preceding transaction commits before this activity starts

Commit after: transaction commits immediately after this activity is completed

Participates: activity runs in existing transaction

Requires Own: activity is isolated in its own transaction.

Usage of BSM vs BPEL process?

• In cases where the state machines are--and will--remain simple, it may be better to use a BPEL process. For example, a state machine without any loops (returning to an earlier state), would probably make more sense being developed as a process.
• However, if there is a lot of looping, the state machine provides a much more natural way to develop, debug, and monitor.
• If you do have performance constraints, then do not prefer BSM as it is internally will get converted into BPEL process by the Process Server runtime.

Compare the Rule sets and Decision Tables?

Rule sets model the typical if-then kind of business rules, if you need to model rules on values from multiple input combinations, then decision tables are preferred.