The

PropertyCollector

requires two fairly complex arguments: the

PropertySpec

and the

ObjectSpec

. The

ObjectSpec

contains instructions to the

PropertyCollector

describing where to look for the desired data. Because configuration information in vSphere is organized like a directory tree, the

ObjectSpec

must describe how to traverse the tree to obtain the desired information. The net result is a complex, nested, and recursive list of instructions. Fortunately, once you have determined the location of all the desired information, the

ObjectSpec

needed to determine the layout of a vSphere object hierarchy can be a static unvarying object. See the code example in section Understanding an ObjectSpec.

The

PropertySpec

is a list of desired property information. Formulating a list that includes all of the desired information can take some effort to compile, but once determined, this can be a static object also.

The data returned from the

PropertyCollector

is a container class called

PropertyFilterUpdate

, which contains an

objectSet

with an item-by-item list of changes to object properties. Every item in this container is identified with one of the following keys: enter (add), leave (delete), and modify. On the first data request, every data item is included, and “enter” is marked for every data item.

The

PropertyCollector

presents its results in what amounts to random order. Since all managed objects have a “parent” property, you can reconstruct the configuration hierarchy by building a tree in memory, using the

parent

identification to organize. The root folder is identified as the only folder without a parent.