- Description
- specifies actions which can be transported with content events.
The situations under which contents will send ContentEvents of the various
action types are described below. The description is broken into a list of
useful definitions, a list of events that happen to contents, and a list of
reactions taken by contents in response to those events.
The definitions are as follows:
| D1 | A content C has an identifier id(C). |
| D2 | A content C is in one of two states, Alive or Deleted.
|
| D3 | A folder content F has a set of children H(F) that is a
set of content identifiers. For example, an "open"
command will usualy return a subset of the contents
denoted by H(F). |
The events that can happen to contents (and that are of interest in this
context) are listed next. Note that 'event' here does not mean an
ContentEvent, but rather some event that occurs either because some content
processes a command, or because a content gets informed about a relevant
change in the underlying system it represents.
| E1 | The identifier of a content C changes from id1(C) == A
to id2(C) == B, denoted as E1(C: A->B). For example,
this event may occur when content C processes a
"setPropertyValues" command changing its "Title" propery,
or when afolder that hierarchicaly contains C changes
its identity. |
| E2 | The state of a content C changes from Alive to Deleted,
denoted as E2(C). For example, this event may occur when
content C processes a "delete" command, or when a content
representing an IMAP message gets informed by the IMAP
server that the message has been deleted. |
| E3 | The set of children of a folder content F is enlarged by
some identifier A (that was not previously in that set,
i.e., !(A in H1(F)) && (A in H2(F))), denoted as E3(F, A).
For example, this event may occur when a new content
created at folder F processes its "insert" command, or
when a folder representing an IMAP mailbox gets informed
by the IMAP server that a new message has arrived at that
mailbox. |
Finally, the list of reactions taken by contents in response to the above
events gives a description of what kinds of ContentEvents are sent in which
situations:
| R1 | E1(C: A->B) results in C sending an EXCHANGED
ContentEvent, which then results in the following: All
folders F that used to have A as a child, but will not
have B as a child, i.e., (A in H1(F)) && !(B in H2(F)),
send a REMOVED ContentEvent. |
| R2 | E2(C) results in C sending a DELETED ContentEvent,
which then results in the following: All folders F that
used to have A as a child, but will not continue to have
A as a child, i.e., (A in H1(F)) && !(A in H2(F)), send
a REMOVED event. |
| R3 | E3(F, A) results in F sending an INSERTED event. |
|
