The Qi4j Core is composed of several artifacts described in this section.
The following figure show the Core artifacts alongside libraries and extensions, and, in green, typical applications artifacts. This is not a full code dependency graph but should give you a good overview of how the pieces fit together. Find out more about each of the Qi4j Core artifacts below.
The Qi4j Core API is the primary interface for client application code during the main execution phase, i.e. after the application has been activated.
Qi4j has a distinct bootstrap phase, also known as the Assembly of an application, where the applications structure is defined programmatically. Once all the layers, modules and all the composite types in each module have been defined the model is instantiated into an application. This enables the entire structure system in Qi4j, where types "belongs" to a module and visibility rules define default behaviors, enforcement of architectural integrity and much more.
Qi4j comes with classes to help with testing. There is also some mocking support, to allow some of Qi4j’s unique aspects to be mocked, but since Qi4j is so flexible at a fine-granular level, we have found that mocking is seldom, if ever, needed.
The Qi4j Core Functional API is a generic package to work with Iterables in a "functional programming language" style.
This package is completely independent of everything else in Qi4j and may be used on its own in any kind of environment such as Spring or Java EE applications.
The Qi4j Core I/O API tries to address the problem around shuffling data around from various I/O inputs and outputs, possibly with transformations and filtering along the way.
The Qi4j Core Runtime has a number of extension points, which we call the Qi4j Core Extension SPI. These are defined interfaces used only by the Core Runtime and never directly by application code. Extensions are assembled in applications during the bootstrap phase.
Your code should never, ever, have a dependency on Qi4j Core Runtime. If you think you need this, you should probably contact qi4j-dev forum at Google Groups and see if your usecase can either be solved in a existing way or perhaps that a new Core Extension SPI is needed.
