Information Technology Reference
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community is introduced to capture the linkage of these roles. This allows
us to express how the organization's contract manager constrains who can
request work to be done under the repair agreement.
If a single enterprise object, such as a salesman, fulfils the Employee role
in the CustomerOrg community and, at the same time, fulfils the User role in
the Phone Repair community, then the behaviours of the two communities are
coupled. Similarly, a single infrastructure manager object might fill both the
Contract Manager role in the CustomerOrg community and the Customer role
in the Phone Repair community. This linkage might, for example, model the
need for the user to be authorized by the contract manager in the customer
organization, and to have this checked against the customer contract held by
the Phone Repair Provider role (see figure 2.6).
In some cases, we want to couple two communities in such a way that two
roles are always linked, whatever object fulfils them. This is often the case
when building a hierarchy of communities. In our scenario, for example, there
is a requirement that a particular HQ system enterprise object fulfils the HQ
system role in the Detailed Phone Repair community and also the role with
the same name in the simplified Branch Repair Provision community; this is
achieved by placing a role-filling constraint on the role in the Branch Repair
Provision community.
We require the HQ system role there to be filled by
«EV_Community»
Phone Repair
has role
«EV_Role»
Phone Repair
Provider
«EV_Role»
Logistics
Provider
«EV_Role»
Customer
«EV_Role»
User
«EV_Role»
Phone
Supplier
«EV_Role»
Bank
«EV_FulfilsRole»
«EV_FulfilsRole»
«EV_Object»
Manager
«EV_Object»
Phone User
«EV_Community»
CustomerOrg
«EV_FulfilsRole»
«EV_FulfilsRole»
has role
«EV_Role»
Contract
Manager
«EV_Role»
Employee
FIGURE 2.6: Linking the Phone Repair and CustomerOrg communities.
