Notification of table changes in an SQLite database http://github.com/groue/GRDB.swift

TableChangeObservers.swift

import Foundation
import GRDB

/// The notification posted when database tables have changed:
let DatabaseTablesDidChangeNotification = "DatabaseTablesDidChangeNotification"
let ChangedTableNamesKey = "ChangedTableNames"

/// TableChangeObserver posts a DatabaseTablesDidChangeNotification on the main
/// thread after database tables have changed.
class TableChangeObserver : NSObject, TransactionObserverType {
    private var changedTableNames: Set<String> = []
    
    func databaseDidChangeWithEvent(event: DatabaseEvent) {
        // Remember the name of the changed table:
        changedTableNames.insert(event.tableName)
    }
    
    func databaseWillCommit() throws {
        // Let go
    }
    
    func databaseDidCommit(db: Database) {
        // Extract the names of changed tables, and reset until next
        // database event:
        let changedTableNames = self.changedTableNames
        self.changedTableNames = []
        
        // Notify
        dispatch_async(dispatch_get_main_queue()) {
            NSNotificationCenter.defaultCenter().postNotificationName(
                DatabaseTablesDidChangeNotification,
                object: self,
                userInfo: [ChangedTableNamesKey: changedTableNames])
        }
    }
    
    func databaseDidRollback(db: Database) {
        // Reset until next database event:
        changedTableNames = []
    }
}


// Register observer

let dbQueue = DatabaseQueue()
let observer = TableChangeObserver()
dbQueue.addTransactionObserver(observer)