In order to create a module you must first create a nicely named directory within the modules conventions directory. For example, let's build a simple hello world module. CommandBox to the rescue!

coldbox create module helloworld

Here is the output:

Created /Users/lmajano/tmp/myapp/modules_app/helloworld
Created /Users/lmajano/tmp/myapp/modules_app/helloworld/handlers
Created /Users/lmajano/tmp/myapp/modules_app/helloworld/handlers/Home.cfc
Created /Users/lmajano/tmp/myapp/modules_app/helloworld/models
Created /Users/lmajano/tmp/myapp/modules_app/helloworld/models/models_here.txt
Created /Users/lmajano/tmp/myapp/modules_app/helloworld/ModuleConfig.cfc
Created /Users/lmajano/tmp/myapp/modules_app/helloworld/views
Created /Users/lmajano/tmp/myapp/modules_app/helloworld/views/home
Created /Users/lmajano/tmp/myapp/modules_app/helloworld/views/home/index.cfm

The layout of a ColdBox Module is optional except for one file: ModuleConfig.cfc. This is a simple CFC that boots up your module and tells the host application how your module is loaded, unloaded and behaves. If you are leveraging CommandBox then you can also declare a box.json for the module itself in order to declare dependencies and development dependencies for it.

Below are all the possible combinations of a module layout, you will notice that it is EXACTLY the same as a ColdBox application.

+Modules_app
  + {ModuleName - Unique}
    + ModuleConfig.cfc (The module configuration object Mandatory)
    + box.json (optional - if using CommandBox)
    + handlers (optional)
    + layouts  (optional)
    + views    (optional)
    + interceptors (optional)
    + models    (optional)

As you can see, the only mandatory resources for a module is the directory name in which it lives and a ModuleConfig.cfc. The module developer can choose to implement a simple module or a very complex module. All folders are optional and only what is used will be loaded. Not only are modules reusable and extensible, but you can easily create a module with dual functionality: A standalone application or a module. This is true reusability and flexibility. I don't know about you, but this is really exciting (Geek Alert!).

If you are picky and you would like to change the folder layout for your module, you can. This is achieved from within the ModuleConfig.cfc by adding a conventions structure that will explain to the ColdBox Module engine how to locate and configure your module.