# A concrete example
At here we would build an Online-Shop based on Nature. The project will involves order, pay, warehouse and delivery domain. Even more we make some statistics through multi-dimensions.
Don't worry about the complexity, we start at simple first, then step by step to achieve the final target. Even thou I think the code lines are great reduced compare to the traditional development, conservative estimate they are less than half.
## How to read it
If you are the first time to know Nature, It's best to view this demo from top to bottom.
Each chapter include little key-points of Nature, this let you come to know Nature.
In the whole demo description. there are some sections titled with **"Nature key points"** that would mind your attention how to do the thing in Nature way.
## Demo projects
Nature have provide all implement for this demo. you will find all of them in the following projects.
- [test entry](https://github.com/llxxbb/Nature-Demo)
- [common defines](https://github.com/llxxbb/Nature-Demo-Common)
- [converter](https://github.com/llxxbb/Nature-Demo-Converter)
- [restful-converter](https://github.com/llxxbb/Nature-Demo-Converter-Restful)
## Let‘s begin
| [prepare](doc/EN/prepare.md) | prepare for the demo | how to run Nature |
| [generate order](doc/EN/emall/emall-1-order-generate.md) | user commit an order into to Nature | `Meta`, master `meta`, define target-state, `Converter` and how to commit business object to Nature |
| [pay for the bill](doc/EN/emall/emall-2-pay-the-bill.md) | user can pay many times for the big bill. | upstream select, state conflict control |
| [stock-out](doc/EN/emall/emall-3-stock-out.md) | the warehouse system is slow to process the order's goods | input state instance, callback |
| [delivery](doc/EN/emall/emall-4-delivery.md) | collaborate with the third-party | parameterization input |
| [signed](doc/EN/emall/emall-5-signed.md) | user received the goods | delay converter |
The following unfinished yet.
| [sale statistics](doc/EN/emall/emall-6-statistics.md) | from goods view, make statistics freely, extensible, no coding. | context, embedded counter, serial process |
| user consumption data | make data which can be got by user id, such as order list | parallel process |