Transaction specification

Transaction Specification

Revision History

Version	User	Date	Notes
0.1	Milko Venkov	Aug 30, 2018	Initial Draft
0.2	Milko Venkov	Sep 04, 2018	Transaction state

1. Overview

Objectives

igx-transaction should be able to plug between given component and its data source. While plugged in igx-transaction should collect all the changes performed in the component without send them to the data source. igx-transaction should update the data source and commit all the changes.

2. User Stories

As an end user, I want

there is no end users stories as igx-transaction should be an Angular Service.

Developer Stories

As a developer, I want to

be able to enable transaction on a given component
be able to retrieve all the transactions - transaction log
be able to get updated state of the data including all changes in the transaction log
be able to update data source with all the changes currently in the transaction log
be able to undo the last change
be able to redo the change that was undone
be able to reset all the changes in the transaction log

3. Functionality

3.1. End User Experience

3.2. Developer Experience

Developers are able to inject the igx-transaction service. Then developers should be able to add changes to the transaction's transaction log. After some changes are added developers should be able to retrieve updated data source state, including all changes in the transaction log; update the data source when needed; reset all the changes in the transaction log; perform undo and redo actions.

Here is what will happen with transaction state when new change is added:

Add change type - when adding such a change one should not provide Initial Value. After successfully adding of such change it will be reflected in aggregated state like Added type. If such a change is then added with Deleted change type it will be removed from aggregated state. Adding of Add change type with id which already exists in aggregated state will throw an exception;
Update change type - when adding such a change one should provide Initial Value. After successfully adding of such change it will be reflected in aggregated state like Updated type. One can also update Added type, this will be reflected in aggregated state like Added type, and Updated type, this will remain like Updated type in aggregated state. If one tries to update Deleted type an exception will be thrown.
Delete change type - when adding such a change one should provide Initial Value. After successfully adding of such change it will be reflected in aggregated state like Deleted type. One can also delete Added type, this will remove the record from the aggregated state, and Updated type, this will change the aggregated type to Deleted. If one tries to delete Deleted type an exception will be thrown.

Here is visual representation of all possible add change paths.

3.3. API

Methods

ITransaction

Name	Description	Parameters
add	Adds a change to the transaction's transaction log	change
get	Gets the respective change according to provided id	id
getAll	Gets all the changes from the transaction log	-
undo	Remove the last change from the transaction log	-
redo	Adds the last undone change to the transaction log	-
currentState	Gets the current state of the changed data	-
update	Commits all the changes to the data source	data
reset	Clears all the changes from the transaction log	-