Difference between revisions of "Namespace"

Revision as of 12:55, 31 January 2012

A namespace is an abstract container or environment created to hold a logical grouping of unique identifiers or symbols (i.e., names). An Identifier defined in a namespace is associated only with that namespace. The same identifier can be independently defined in multiple namespaces. That is, the meaning associated with an identifier defined in one namespace may or may not have the same meaning as the same identifier defined in another namespace.

For example, Bill works for company X and his employee ID is 123. Jane works for company Y and her employee ID is also 123. The reason Bill and Jane can be identified by the same ID number is because they work for different companies. The different companies in this case would symbolize different namespaces. There would be serious confusion if the two people worked for the same company, and still had the same employee ID. For instance, a paycheck issued to employee ID 123 would not identify which person should receive the check.

In large computer programs or documents it is not uncommon to have hundreds or thousands of identifiers. Namespaces provide a mechanism for hiding local identifiers. They provide a means of grouping logically related identifiers into corresponding namespaces, thereby making the system more modular.

Namespaces are stored on every Metaobject. The Metaobjects´ translation process reads the namespaces and attaches it to the standard namespace („UBIK.Runtime“ or „UBIK.Runtime.UI“). In the Treeview the Views Inheritance and Contentview are getting grouped and sorted by namespace.

Namespaces for systemcontentobjects

Every systemcontentobject owns or is able to own the property namespace. The name of this property is given to the object as a namespace. If the value is empty or the property does not exist, the metaobjects´ namespace will be generated. It is also possible, that objects do have an empty namespace property. The systemcontentobjects will be sorted via namespace and displayed in the Contentview.

Namespaces for standardcontentobjects

The namespace of a contentobject is default a emptystring. If necessary, the property namespace can be attached to a contentobject. In this case the returnvalue is the properties value. It is recommended to not use this type of implementation.