[PlantUML] To-Do List Class Diagram

package User {
class User <<M,#FF447F>> {
    userID : integer
    username : string
    password : string
    email : string
    active : boolean
}

class AccountView <<V,lightgreen>> {
    showLoginPage()
}

class AccountController <<C,lightblue>> {
    deleteAccount(User)
}
}

package Category {
class Category <<M,#FF447F>> {
    categoryID : integer
    name : string

    addListElement(ListElement)
}

class CategoryView <<V,lightgreen>> {
    showDuplicationDialog(Category)
    delete(Category)
    update()
}

class CategoryController <<C,lightblue>> {
    removeUser(Category, User)
    duplicate(Category, User)
}
}

package ListElement {
class ListElement <<M,#FF447F>> {
    itemID : integer
    timestampCreated : timestamp
    title : string
    dueDate : date
    timestampDate : timestamp
    taskCompleted : boolean
    flag : boolean
    deleted : boolean

    delete()
}

class Description <<M,#FF447F>> {
    description : string
    timestamp : timestamp
}

class ListElementView <<V,lightgreen>> {
    showRecoveryDialog(ListElement)
    showConflict(Description)
    confirmDeletion()
    update()
}

class ListElementController <<C,lightblue>> {
    updateDescription(ListElement, Description)
    deleteElement(ListElement, TimeStamp)
    setFlag(ListElement, Boolean)
    updateElementOwner(User)
    duplicate(ListElement)
    restore(ListElement)
}
}

class DatabaseController <<C,lightblue>> {
    getListElements(Category, User)
    getListElements(Category)
    getListElements(User)
    addDescription(ListElement, Description)
    getDescription(ListElement, Integer)
    deleteListElement(ListElement)
    addListElement(ListElement)
    deleteCategory(Category)
    addCategory(Category)
    deleteUser(User)
}

ListElement *-- Description
Category o-- ListElement

AccountController -> AccountView
AccountController -down-> User
AccountController -> DatabaseController

CategoryController -> CategoryView
CategoryController -down-> Category
CategoryController -> DatabaseController

ListElementController -down-> ListElementView
ListElementController -> ListElement
ListElementController -> DatabaseController

DatabaseController -> User
DatabaseController -> Category
DatabaseController -> ListElement