OSID - osid.checklist.TodoHierarchyDesignSession Service Interface Definition

Interface	osid.checklist.TodoHierarchyDesignSession
Implements	`osid.OsidSession`
Used By	`osid.checklist.ChecklistManager`
Used By	`osid.checklist.ChecklistProxyManager`
Description	This session defines methods for managing a hierarchy of `Todos`. Each node in the hierarchy is a unique `Todo`.
Method	getTodoHierarchyId
Description	Gets the hierarchy `Id` associated with this session.
Return	`osid.id.Id`		the hierarchy `Id` associated with this session
Compliance	`mandatory`		This method must be implemented.
Method	getTodoHierarchy
Description	Gets the hierarchy associated with this session.
Return	`osid.hierarchy.Hierarchy`		the hierarchy associated with this session
Errors	OPERATION_FAILED		unable to complete request
Errors	PERMISSION_DENIED		authorization failure
Compliance	`mandatory`		This method must be implemented.
Method	canModifyTodoHierarchy
Description	Tests if this user can change the hierarchy. A return of true does not guarantee successful authorization. A return of false indicates that it is known performing any update will result in a `PERMISSION_DENIED`. This is intended as a hint to an application that may opt not to offer these operations to an unauthorized user.
Return	`boolean`		`false` if changing this hierarchy is not authorized, `true` otherwise
Compliance	`mandatory`		This method must be implemented.
Method	addRootTodo
Description	Adds a root todo.
Parameters	`osid.id.Id`	`todoId`	the `Id` of a todo
Errors	ALREADY_EXISTS		`todoId` is already in hierarchy
	NOT_FOUND		`todoId` not found
	NULL_ARGUMENT		`todoId` is `null`
	OPERATION_FAILED		unable to complete request
	PERMISSION_DENIED		authorization failure
Compliance	`mandatory`		This method must be implemented.
Method	removeRootTodo
Description	Removes a root todo.
Parameters	`osid.id.Id`	`todoId`	the `Id` of a todo
Errors	NOT_FOUND		`todoId` not a root node
	NULL_ARGUMENT		`todoId` is `null`
	OPERATION_FAILED		unable to complete request
	PERMISSION_DENIED		authorization failure
Compliance	`mandatory`		This method must be implemented.
Method	addChildTodo
Description	Adds a child to a todo.
Parameters	`osid.id.Id`	`todoId`	the `Id` of a todo
Parameters	`osid.id.Id`	`childId`	the `Id` of the new child
Errors	ALREADY_EXISTS		`todoId` is already a parent of `childId`
	NOT_FOUND		`todoId` or `childId` not found
	NULL_ARGUMENT		`todoId` or `childId` is `null`
	OPERATION_FAILED		unable to complete request
	PERMISSION_DENIED		authorization failure
Compliance	`mandatory`		This method must be implemented.
Method	removeChildTodo
Description	Removes a child from a todo.
Parameters	`osid.id.Id`	`todoId`	the `Id` of a todo
Parameters	`osid.id.Id`	`childId`	the `Id` of the new child
Errors	NOT_FOUND		`todoId` not a parent of `childId`
	NULL_ARGUMENT		`todoId` or `childId` is `null`
	OPERATION_FAILED		unable to complete request
	PERMISSION_DENIED		authorization failure
Compliance	`mandatory`		This method must be implemented.
Method	removeChildTodos
Description	Removes all children from a todo.
Parameters	`osid.id.Id`	`todoId`	the `Id` of a todo
Errors	NOT_FOUND		`todoId is` not in hierarchy
	NULL_ARGUMENT		`todoId` is `null`
	OPERATION_FAILED		unable to complete request
	PERMISSION_DENIED		authorization failure
Compliance	`mandatory`		This method must be implemented.