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. |
This action must be notified at the listeners of the folder content. */ const long INSERTED = 0; //------------------------------------------------------------------------- /** A content was removed from a folder content, but not physically destroyed (i.e., due to rules just applied to the folder).
This action must be notified at the listeners of the folder content. */ const long REMOVED = 1; //------------------------------------------------------------------------- /** A content was physically destroyed.
Events containing this action may be generated at any time. So a content event listener should be prepared to get notified the "death" of the related content!
This action must be notified at the listeners of the deleted content. */ const long DELETED = 2; //------------------------------------------------------------------------- /** This Action indicates that a content has changed its identity (i.e. after renaming a file system folder).
This action must be notified at the listeners of the exchanged content. */ const long EXCHANGED = 4; //------------------------------------------------------------------------- /** This is obsolete and should no longer be used. @deprecated */ const long SEARCH_MATCHED = 128; }; //============================================================================= }; }; }; }; #endif