タスクの種類
XPDLでは、タスクに複数の種類があります。ひとまず仕様書を抜粋して、一覧にしました。ちょっと違いの分からないものがいくつかあります。
- TaskService
- A Service Task is a Task that provides some sort of service, which could be a Web service or an automated application.
- TaskSend
- A TaskType of Send MUST NOT have an incoming Message Flow. A Send Task is a simple Task that is designed to send a message to an external participant (relative to the Business Process). Once the message has been sent, the Task is completed.
- TaskReceive
- A TaskType of Receive MUST NOT have an outgoing Message Flow. A Receive Task is a simple Task that is designed to wait for a message to arrive from an external participant (relative to the Business Process). Once the message has been received, the Task is completed.
- TaskUser
- A User Task is a typical workflow task where a human performer performs the Task with the assistance of a software application and is scheduled through a task list manager of some sort.
- TaskManual
- A TaskType of Manual MUST NOT have an incoming or an outgoing Message Flow.
- TaskApplication
- The Activity is implemented by (one or more) tools. A tool may be an application program (link to entity Application); which may be invoked via Interface 3 (WfMC) - see the Workflow Client Application API (WAPI - Interface 2).
- TaskScript
- A Task Type of Script MUST NOT have an incoming or an outgoing Message Flow. A Script Task is executed by a business process engine. The modeler or implementer defines a script in a language that the engine can interpret. When the Task is ready to start, the engine will execute the script. When the script is completed, the Task will also be completed.
- TaskReference
- There may be times where a modeler may want to reference another activity that has been defined.
BPMNでも、タスクに複数の種類があるので、同じく一覧にします。
- Service Task
- A Service Task is a Task that uses some sort of service, which could be a Web service or an automated application.
- Send Task
- A Send Task is a simple Task that is designed to send a Message to an external Participant (relative to the Process). Once the Message has been sent, the Task is completed.
- Receive Task
- Receive Task is a simple Task that is designed to wait for a Message to arrive from an external Participant (relative to the Process). Once the Message has been received, the Task is completed.
- User Task
- A User Task is a typical “workflow” Task where a human performer performs the Task with the assistance of a software application and is scheduled through a task list manager of some sort.
- Manual Task
- A Manual Task is a Task that is expected to be performed without the aid of any business process execution engine or any application. An example of this could be a telephone technician installing a telephone at a customer location.
- Business Rule Task
- A Business Rule Task provides a mechanism for the Process to provide input to a Business Rules Engine and to get the output of calculations that the Business Rules Engine might provide.
- Script Task
- A Script Task is executed by a business process engine. The modeler or implementer defines a script in a language that the engine can interpret. When the Task is ready to start, the engine will execute the script. When the script is completed, the Task will also be completed.
XPDL と BPMN は相互参照しながら仕様を策定していると思われるので、まず似ていると思うのですが、この部分はまったく一緒といっても良さそうですね。文章もコピーしたと思われます。
以下に一覧としてまとめました。
| BPMN | XPDL | 説明 |
|---|---|---|
| Service Task | TaskService | サービス（典型的にはWebサービス）によって実行されるタスク |
| Send Task | TaskSend | プロセスに関係している外部のParticipant（人や組織とは限らない）にメッセージを送るタスク |
| Receive Task | TaskReceive | プロセスに関係している外部のParticipant（人や組織とは限らない）からメッセージを受け取るタスク |
| User Task | TaskUser | ソフトウェアを使って、人によって処理されるタスク。いわゆるワークフローシステムにおけるタスク |
| Manual Task | TaskManual | ソフトウェアの助けを借りずに、人によって処理されるタスク。 |
| Business Rule Task | - | Business Rule Engine によって処理されるタスク。Service Task の特別なものと考えるべきか。 |
| - | TaskApplication | 何らかのアプリケーションによって処理されるタスク。Workflow Client Application API (WAPI) を介して実行される想定。 |
| Script Task | TaskScript | BusinessProcessEngine 自信によって、自動処理されるタスク。処理内容はスクリプトによって記述される。 |
| - | TaskReference | 他のタスク定義を参照する。複数同じ定義を行う場合に使用する。 |
XPDL における TaskApplication の位置づけが正直よく解らないのですが、それ以外は解りやすいです。何らかのソフトウェアによって自動処理されるものが、Service Task, Business Rule Task, Script Task の3種類で、人によって処理されるものが User Task と Manual Taskの2種類。人かソフトウェアか、プロセスの外部にメッセージを送信 or 受信するだけのものが、Send Task, Receive Task になります。
