DDD Aggregate Example 1

@startuml
allow_mixing
skinparam componentStyle rectangle

component "BacklogItem Aggregate" {
    component "BacklogItem" as BacklogItemC <<aggregate root>>
    component "State" as StateC <<value object>>
    component "Task" as TaskC <<entity>>
}

BacklogItemC -- StateC
BacklogItemC -- "many" TaskC

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package Classes <<Rectangle>> {
    package BacklogItemAggregate {
        class BacklogItem <<aggregate root>> {
          - String id
          - State state
          - List<Task> tasks
          + BacklogItem(...)
          + Task getTaskByID(String taskID)
          + int getTotalHoursRemaining()
          + setState(State state)
        }
        enum State <<value object>> {
            IN_PROGRESS
            DONE
        }
        class Task <<entity>> {
          - String id
          - int hoursRemaining
          + Task(...)
          + void setHoursRemaining(int hours)
        }
    }

    BacklogItem *-- State
    BacklogItem *-- "many" Task
}

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object backlogItem <<aggregate root>> {
    id: "ADD_PRICE"
}
object state <<value object>> {
    IN_PROGRESS
}
object task <<entity>> {
    id: "CREATE_FIELD"
    hoursRemaining: 12
}

backlogItem *-- state
backlogItem *-- task

note as N
<code>
String taskID = "CREATE_FIELD";
var task = new Task(taskID, 1);
var backlogItem = new BacklogItem("ADD_PRICE", Status.IN_PROGRESS, List.of(task));

backlogItemRepository.save(backlogItem)
</code>
end note

newpage

object backlogItem <<aggregate root>> {
    id: "ADD_PRICE"
}
object state <<value object>> {
    IN_PROGRESS
}
object task <<entity>> {
    id: "CREATE_FIELD"
    hoursRemaining: 0
}
backlogItem *-- state
backlogItem *-- task

note as N
<code>
var backlogItem = backlogItemRepository.findById('ADD_PRICE');
var task = backlogItem.getTaskByID('CREATE_FIELD');
task.setHoursRemaining(0);

backlogItemRepository.save(backlogItem);
</code>
end note

newpage

object backlogItem <<aggregate root>> {
    id: "ADD_PRICE"
}
object state <<value object>> {
    DONE
}
object task <<entity>> {
    id: "CREATE_FIELD"
    hoursRemaining: 0
}
backlogItem *-- state
backlogItem *-- task

note as N
<code>
var backlogItem = backlogItemRepository.findById('ADD_PRICE');
var task = backlogItem.getTaskByID('CREATE_FIELD');

task.setHoursRemaining(0);
if (backlogItem.getTotalHoursRemaining() == 0) {
    backlogItem.setState(State.DONE)
}

backlogItemRepository.save(backlogItem);
</code>
end note

newpage

package Classes <<Rectangle>> {
    package BacklogItemAggregate {
        class BacklogItem <<aggregate root>> {
          - String id
          - State state
          - List<Task> tasks
          - int getTotalHoursRemaining()
          + BacklogItem(...)
          + setHoursRemainingForTask(String taskID, int hours)
        }
        enum State <<value object>> {
            IN_PROGRESS
            DONE
        }
        class Task <<entity>> {
          - String id
          - int hoursRemaining
          + Task(...)
          ~ void setHoursRemaining(int hours)
        }
    }

    BacklogItem *-- State
    BacklogItem *-- "many" Task
}

newpage

object backlogItem <<aggregate root>> {
    id: "ADD_PRICE"
}
object state <<value object>> {
    DONE
}
object task <<entity>> {
    id: "CREATE_FIELD"
    hoursRemaining: 0
}
backlogItem *-- state
backlogItem *-- task

note as N
<code>
BacklogItem {
 void setHoursRemainingForTask(String taskID, int hours) {
    task.setHoursRemaining(hours);
    if (getTotalHoursRemaining() == 0) {
        backlogItem.setState(State.DONE)
    }
 }
}

var backlogItem = backlogItemRepository.findById('ADD_PRICE');
var task = backlogItem.setHoursRemainingForTask('CREATE_FIELD', 0);

backlogItemRepository.save(backlogItem);
</code>
end note

newpage

@enduml