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                     The Messaging OSID sends and receives messages.   
                     Messages  
                    
                      Messages  are structures that include a 
                    sender, recipients, and a timestamp. A  Message 
                     is created using a  MessageAdminSession. 
                     The text of the  Message  is 
                    displayable as text and may include a specific structure 
                    defined using a  MessageRecord.    
                    
                     Until a  Message  is sent, it is stored 
                    and may be edited as a draft. Once a  Message 
                     is sent, the  Message  includes the 
                    sending  Agent  as well as the addressed 
                    recipients represented by a list of  Resources. 
                     A  Message  is received by a 
                    receiving  Agent  which generally is related 
                    to one of the recipients.   
                     Sending Messages  
                    
                     Once a Message has been created, it may be sent from 
                    the authenticated  Agent to a specified list of 
                    recipients  using the  MessagingSession. 
                     The same  Message  may be sent to 
                    additional recipients by returning to the  
                    MessagingSession  and using the same  Message 
                      Id.    
                     Receiving Messages  
                    
                     The  MessageLookupSession  can be used to 
                    retrieve incoming  Messages.  From the point 
                    of view of the receiving  Agent,   
                    Messages  from the  MessageLookupSession 
                     indicate a foreign  Agent  as the 
                    sender and at least one recipient related to the 
                    authenticated  Agent  which generally, but 
                    may not always, be the receiving  Agent.  
                      
                    
                     The same interfaces are used to receive  
                    Messages  as well as examine created  
                    Messages.  The  Messages  seen in the 
                     MessageLookupSession  vary depending on the 
                    point of view implied by the  Mailbox  
                    catalog.   
                     Message Receipts  
                    
                     Once a  Message  has been received by a 
                    receiving  Agent,  a  Receipt  
                    is be generated to include the time receive and the 
                    receiving  Agent.  A  Receipt  
                    can be used to store additional data related to the 
                    received  Message.    
                    
                      Receipts  may only be visible to the 
                    receiving  Agent  or a Messaging OSID 
                    Provider may authorize  Receipts  to be 
                    visible to the sender or other parties.   
                     Mailbox Catalogs  
                    
                      Messages  are cataloged using  
                    Mailboxes.  Mailboxes be may used to store messages 
                    for different users, and may also be used to provide 
                    message folders for each user. Like all  
                    OsidCatalogs,  a  Mailbox  may belong 
                    to a federated hierarchy to provide fedeated and filtering 
                    views among multiple mailboxes.   
                     On Resource & Agents  
                    
                     The  Agent  is the identity of an 
                    authenticated actor while the  Resource  
                    represents a real-world entity such as a person or 
                    organization. The mapping between  Agents  
                    and  Resources  is managed by the Resource 
                    OSID. In the Messaging OSID, an  Agent  sends 
                    a  Message  to a  Resource,  
                    However, aspects of the service also examine messages from 
                    the recipient's point of view where the sender appears as 
                    an object instead of an actor. The Messaging OSID 
                    references both a sender as a  Resource  and 
                    asending agent as an  Agent.  The Messaging 
                    OSID Provider orchestrates the mapping between  
                    Agents  and  Resources  as a messaging 
                    application would access a local address book for looking 
                    up full names corresponding to incoming email addresses. 
                      
                     Sub Packages  
                    
                     The Messaging OSID contains a Messaging Batch OSID for 
                    managing  Messages  and  Mailboxes 
                     in bulk.  
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