The Tcomponent type is the base type for top-level
Blueprint components.  The <bean> <reference>, <service>,
and <reference-list> elements are all derived from
the Tcomponent type.  This type defines an id attribute
that is used create references between different components.
Component elements can also be inlined within other component
definitions.  The id attribute is not valid when inlined.

The activation attribute for this component.  This can either
be "eager" or "lazy".  If not specified, it
defaults to default-activation attribute of the enclosing
<blueprint> element.

depends-on identifies (by id) other components that this component
depends on.  The component only be activated after the
depends-on components are successfully activated.  Also, if there
are <reference> or <reference-list> elements with unstatisfied
manadatory references, then the depends-on relationship will also
be used to determine whether this service is enabled or not.