A company wants to automate its task allocation process. Currently, employees are assigned tasks either verbally or via email, and it is very hard to keep track of who is doing what, and how much is done. The company wants to move to a web-based task allocation system to do the following.
Anyone can create a task. Each task gets a corresponding ticket number. One user is assigned as “responsible” for the task, and others can be assigned as “helpers”. Admins create and delete user accounts (individually, or in bulk via a CSV file).
When a task is created, by default the creator is “responsible” for it unless it is changed. Admins can also change the responsible person. The creator, or the current responsible person, can also change the assignment. The responsible person can add/remove helpers.
Responsible persons and helpers can post against a task. Once a task is complete, its status has to be changed to complete. Tasks can be in different statuses: Not initiated, initiated, progressing, stalled, waiting for resources, completed, unresolved being some of them.
When creating a task, the creator has to give a task title and a short description of no less than 50 words. He/She can assign the responsible person and/or helpers. He/she can also attach watchers to the task. All stakeholders, the creator, responsible person, helpers, and watchers should be notified with every post on the task.
Tasks can be dependent on other tasks, meaning they will never achieve the complete status, unless the other tasks are completed. Tasks can also have sub-tasks (not the same as a dependency), which can be created and assigned to other responsible people, but the responsible person on the main task will automatically become a watcher of the sub-tasks, as well as the tasks on which there is a dependency.
Task posts are mainly text, but can also have attachments. Each attachment is by default displayed as a simple url (for download), but may also go through one or more “presentation-filters”. For example, if the attachment is a video, the user can choose to show it in a player. The user may also choose to apply the “minification-filter” to the video player, which will allow users to mininmize the player to save space.
Whenever an attachment is added, the user adding the attachment can choose one or more “presentation-filters” to be applied in composition to the attachment. Examples of some other filters are scanning for viruses, generating thumbnails, mouseover preview, etc.
Draw a sequence diagram showing the interaction between objects for “adding a videoattachment to a post ”.