question: private boolean isKnownVersion ( long version ) { if ( version > currentVersion || version < 0 ) { return false ; } if ( version == currentVersion || chunks . size ( ) == 0 ) { return true ; } Chunk c = getChunkForVersion ( version ) ; if ( c == null ) { return false ; } MVMap < String , String > oldMeta = getMetaMap ( version ) ; if ( oldMeta == null ) { return false ; } try { for ( Iterator < String > it = oldMeta . keyIterator ( "chunk." ) ; it . hasNext ( ) ; ) { String chunkKey = it . next ( ) ; if ( ! chunkKey . startsWith ( "chunk." ) ) { break ; } if ( ! meta . containsKey ( chunkKey ) ) { String s = oldMeta . get ( chunkKey ) ; Chunk c2 = Chunk . fromString ( s ) ; Chunk test = readChunkHeaderAndFooter ( c2 . block ) ; if ( test == null || test . id != c2 . id ) { return false ; } chunks . put ( c2 . id , c2 ) ; } } } catch ( IllegalStateException e ) { return false ; } return true ; }
target:  Check whether all data can be read from this version. This requires that all chunks referenced by this version are still available (not overwritten).