question: private Map < Long , Pair < String , Long > > recoverPendingLargeMessages ( ) throws Exception { Map < Long , Pair < String , Long > > largeMessages = new HashMap < > ( ) ; List < String > filenames = largeMessagesFactory . listFiles ( "msg" ) ; List < Long > idList = new ArrayList < > ( ) ; for ( String filename : filenames ) { Long id = getLargeMessageIdFromFilename ( filename ) ; if ( ! largeMessagesToDelete . contains ( id ) ) { idList . add ( id ) ; SequentialFile seqFile = largeMessagesFactory . createSequentialFile ( filename ) ; long size = seqFile . size ( ) ; largeMessages . put ( id , new Pair < > ( filename , size ) ) ; } } return largeMessages ; }
target:  Sets a list of large message files into the replicationManager for synchronization. <p> Collects a list of existing large messages and their current size, passing re. <p> So we know how much of a given message to sync with the backup. Further data appends to the messages will be replicated normally.