The link-method attribute determines what happens when the composite repository needs to get a property value that belongs to a contributing repository item. For example, a process might call:

CompositeItem.getPropertyValue("ldapFirstName");

where ldapFirstName is a property of a contributing repository item in an LDAP repository. The CompositeItem that is being asked for the property needs to look for this contributing item. If it can find it, it retrieves the property value and acts according to the value of the link-method attribute: static or dynamic.

Static link method

If link-method is set to static, the contributing item is stored in a member variable of that composite repository item. The next time a property is requested from that same item, it retrieves it from this variable instead of finding it again from the underlying contributing repository. This saves some computational effort and results in faster property retrieval.

If the value of the property or properties used to link to the underlying contributing item changes, the data in the member variable is stale. This occurs only if a linking property in the underlying data store changes. For example, if you link to a contributing item descriptor using a login property, static linking can result in stale data only if the login property changes in an underlying repository.

Dynamic link method

If link-method attribute is set to dynamic, the composite repository queries the underlying repository for the contributing item every time a property is requested from it. This might result in slower performance, but it also means that data is never out of sync at the repository level.

Methods compared

Dynamic link mode might seem like the most technically correct implementation, because the data model is guaranteed to reflect the latest information. Because dynamic link mode requires a query each time information is needed from a composite item, it can impair performance. Usually, the information that links items rarely changes. Static linking is generally provides correct data model linking.