# 3.1. Business Context The Common Service is a central service used by many other services of the Transport Management (TMS) domain and the Warehouse Management (WMS) domain. It does not depend or use other OpenWMS.org services, hence it can be seen as one of the essential base services of each system.

Name	Responsibility
Common Service	Base service of the COMMON domain responsible to manage `TransportUnits`, `Locations` and `LocationGroups`. Functionality if offered as a REST API over HTTP and an asynchronous command API
User Interface	An user interface, ie. for operators, may interact with the Common Service
Transport Management Services	All services of the automatic and manual transport management may access the Common Service directly
Warehouse Management Services	All services of the warehouse management domain may interact with the Common Service directly

Exposed resources to API clients

Name	Responsibility
Location	A `Location`, represents a physical or virtual place in a warehouse. Could be something like a storage location in the stock or a conveyor location. Even error locations can be represented with the `Location`. Multiple Locations with same characteristics are grouped to a `LocationGroup`
LocationType	A `LocationType` is the type of `Locations` with same characteristics
LocationGroup	A `LocationGroup` is a logical group of `Locations` with same characteristics
Target	A `Target` is either a physical or a logical endpoint of any kind of warehouse order. A `TransportOrder` has a `Target` assigned where it has to be moved to
Account	An `Account` encapsulates identifying information about the actual cost center
TransportUnit	A `TransportUnit` is an item like a box, a toad, a bin or a pallet that is moved within a warehouse and can carry goods. It can be moved between `Location`s
TransportUnitType	A `TransportUnitType` is a type of a certain `TransportUnit`. Typically to store characteristic attributes of `TransportUnits`, such as the length, the height, or the weight of `TransportUnits`
TypeStackingRule	A `TypeStackingRule` is a `Rule` that defines what `TransportUnitType` can be stacked on other types
TypePlacingRule	A `TypePlacingRule` is a `Rule` that defines what types of `TransportUnits` can be put on what type of `Location`

# 3.2. Technical Context The Technical Context illustrates interfaces (channels and transmission media) linking the system to its environment. In addition a mapping of domain specific input/output to the channels, i.e. an explanation with I/O uses which channel. The Common Service exposes several resources over HTTP REST. The current available and detailed interface description can be found [here](https://openwms.github.io/org.openwms.common.service/rest/2.0.0-SNAPSHOT/api.html). In addition the service sends event notifications out to surrounding services about master data changes and actions that occur within the service. It offers an asynchronous API to trigger actions via commands from the outer world.

Name	Type	Responsibility
REST API	Synchronous API over HTTP	API to retrieve data from and to trigger actions on the Common domain objects
common.lg	RabbitMQ Exchange	Outgoing exchange to send events according to changes on `Locations` and `LocationGroups`
common.tu	RabbitMQ Exchange	Outgoing exchange to send events according to changes on `TransportUnits` and `TransportUnitTypes`
common.tu.commands	RabbitMQ Exchange	An exchange where the Common Service listens on commands and requests from other services
common-tu-commands-queue	RabbitMQ Queue	A queue bound to the own exchange to receive incoming commands or requests