Glossary

This is a list of some common words that should have the same meaning throughout Zope. It is not exhaustive.

ID

The term ‘id’ should only be used when we are talking about an identifier that is unique in the context of some particular id scheme. Examples include

• A social security number, unique within a country’s social secuity bureaucracy
• A user id consisting of an NT Domain and a username, unique within a Windows NT network
• A user id, unique within a Windows NT Domain
• A Windows NT domain, unique within a Windows network

We could consider the name of an object within a container to be an id within the id scheme of that container, but this is not a particularly useful way of thinking. One reason is that to identify the container, we need to consider it as having an id within the id scheme of its container.

Id schemes should really be well-known points of reference within a system. So, the model of Services in Zope 3 fits; you look up a service by its id within the service manager id scheme.

Key

We use an object’s name to get it from within a container. The container sees these names as ‘keys’, so from a container’s point of view, a name functions as a key to look up an object.

When we use the term ‘key’, we really mean “a name functioning as a key in the context of a container”.

Manager

1. A user that configures components, such as a SiteManager.
2. An object that performs through the web configuration, such as a ServiceManager (which allows site managers to configure services.)

Generally, the word ‘manager’ is inappropriate for objects that don’t perform through-the-web configuration. For example, global “service services” are not configurable through the web, but they were once called “service managers”, and have now been renamed, since the name caused confusion with through-the-web configurable service managers.

Name

Objects are given names to help us find them. An object may be found via more than one name. In the Zope Toolkit, we use names to guide the process of traversing from a container to a contained object.

ZCML

Zope Configuration Markup Language. An XML-based language used to configure software components.

References

Martin Fowler, “Analysis Patterns: reusable object models”, Addison Wesley 1997. Chapter 5 “Referring to Objects” has a good discussion of names, ids and id schemes.