realm encapsulates class sample code in swift 3.0

preface

If you've had enough of FMDB or CoreData, try realm. This article mainly introduces the content of realm encapsulation class in swift 3.0.

Latest update, special thanks @deepindo

 ///  Query all data after sorting , Keywords and whether ascending order 
 static func selectScoretByAll<T: Object>(_: T.Type ,key: String, isAscending: Bool) -> Results<T>{
  return sharedInstance.objects(T.self).sorted(byProperty: key, ascending: isAscending)
 }

import UIKit
import RealmSwift

class ZYWRealm: NSObject {

 
 /// realm  Database name 
 static let username = "MY-DB"
 
 static let sharedInstance = try! Realm()
 
 //--MARK:  Initialize the  Realm
 ///  Initializes in encrypted  Realm .   encrypted  Realm  This will result in minimal additional resource usage (usually slower than normal at most) 10% ) 
 static func initEncryptionRealm() {
  //  Description:   The following can be combined, but in order to maximize the display of the content of each operation, it is set separately  Realm
  
  //  Generate a random key 
  var key = Data(count: 64)
  
  _ = key.withUnsafeMutableBytes {mutableBytes in
   SecRandomCopyBytes(kSecRandomDefault, key.count, mutableBytes)
  }
 
  //  For encryption  Realm  File configuration file 
  var config = Realm.Configuration(encryptionKey: key)
  
  //  Use the default directory, but use the user name instead of the default file name 
  config.fileURL = config.fileURL!.deletingLastPathComponent().appendingPathComponent("\(username).realm")
  
  //  Get our  Realm  The parent directory of the file 
  let folderPath = config.fileURL!.deletingLastPathComponent().path
  
  /**
   *  Settings can be used in background application refresh  Realm
   *  Note: the following operations are actually closed  Realm  Of the file  NSFileProtection  Property encryption, which reduces the file protection property to 1 A less restrictive property that allows access to files even when the device is locked 
   */
  //  Unguard this directory 
   try! FileManager.default.setAttributes([FileAttributeKey.protectionKey: FileProtectionType.none], ofItemAtPath: folderPath)

  
  //  Apply this configuration to the default  Realm  In the database 
  Realm.Configuration.defaultConfiguration = config
  
 }
 
 ///  Initialize the default  Realm
 static func initRealm() {
  var config = Realm.Configuration()
  
  //  Use the default directory, but use the user name instead of the default file name 
   config.fileURL = config.fileURL!.deletingLastPathComponent().appendingPathComponent("\(username).realm")

  //  Get our  Realm  The parent directory of the file 
  let folderPath = config.fileURL!.deletingLastPathComponent().path
  
  //  Unguard this directory 
  try! FileManager.default.setAttributes([FileAttributeKey.protectionKey: FileProtectionType.none],
               ofItemAtPath: folderPath)
  
  //  Apply this configuration to the default  Realm  In the database 
  Realm.Configuration.defaultConfiguration = config
 }
 
 //--- MARK:  operation  Realm
 ///  Do write 
 static func doWriteHandler(_ clouse: @escaping ()->()) { //  It's used here  Trailing  closure 
  try! sharedInstance.write {
   clouse()
  }
 }
 
 /// Write in the background 
 
 static func BGDoWriteHandler(_ clouse: @escaping ()->()) {
  try! Realm().write {
   clouse()
  }
 }
 
 ///  add 1 The data 
 static func addCanUpdate<T: Object>(_ object: T) {
  try! sharedInstance.write {
   sharedInstance.add(object, update: true)
  }
 }
 static func add<T: Object>(_ object: T) {
  try! sharedInstance.write {
   sharedInstance.add(object)
  }
 }
 ///  Background separate process writes 1 Set of data 
 static func addListDataAsync<T: Object>(_ objects: [T]) {
    
  
  let queue = DispatchQueue.global(priority: DispatchQueue.GlobalQueuePriority.default)
  // Import many items in a background thread
  queue.async {
   //  Why add the following keywords, see  Realm  The comment that the file deleted 
   autoreleasepool {
    //  Get in this thread  Realm  And table instance 
    let realm = try! Realm()
    //  Bulk write operation 
    realm.beginWrite()
    // add  Method supports  update  . item  The object must have a primary key 
    for item in objects {
     realm.add(item, update: true)
    }
    //  Commit write transactions to ensure data is available on other threads 
    try! realm.commitWrite()
   }
  }
 }
 
 static func addListData<T: Object>(_ objects: [T]) {
  autoreleasepool {
   //  Get in this thread  Realm  And table instance 
   let realm = try! Realm()
   //  Bulk write operation 
   realm.beginWrite()
   // add  Method supports  update  . item  The object must have a primary key 
   for item in objects {
    realm.add(item, update: true)
   }
   //  Commit write transactions to ensure data is available on other threads 
   try! realm.commitWrite()
  }
 }
 
 ///  Delete some data 
 static func delete<T: Object>(_ object: T) {
  try! sharedInstance.write {
   sharedInstance.delete(object)
  }
 }
 
 ///  Batch deletion of data 
 static func delete<T: Object>(_ objects: [T]) {
  try! sharedInstance.write {
   sharedInstance.delete(objects)
  }
 }
 ///  Batch deletion of data 
 static func delete<T: Object>(_ objects: List<T>) {
  try! sharedInstance.write {
   sharedInstance.delete(objects)
  }
 }
 ///  Batch deletion of data 
 static func delete<T: Object>(_ objects: Results<T>) {
  try! sharedInstance.write {
   sharedInstance.delete(objects)
  }
 }
 
 ///  Batch deletion of data 
 static func delete<T: Object>(_ objects: LinkingObjects<T>) {
  try! sharedInstance.write {
   sharedInstance.delete(objects)
  }
 }
 
 
 ///  Delete all data. Pay attention to, Realm  The size of the file will not change because it will reserve space for storing data quickly later 
 static func deleteAll() {
  try! sharedInstance.write {
   sharedInstance.deleteAll()
  }
 }
 
 ///  Query the data according to the conditions 
 static func selectByNSPredicate<T: Object>(_: T.Type , predicate: NSPredicate) -> Results<T>{
  return sharedInstance.objects(T.self).filter(predicate)
 }
 
 ///  The background queries the data according to the conditions 
 static func BGselectByNSPredicate<T: Object>(_: T.Type , predicate: NSPredicate) -> Results<T>{
  return try! Realm().objects(T.self).filter(predicate)
 }

 
 ///  Query all data 
 static func selectByAll<T: Object>(_: T.Type) -> Results<T>{
   return sharedInstance.objects(T.self)
 }
 //--- MARK:  delete  Realm
 /*
   Refer to the official documentation, all  fileURL  Point to what you want to delete  Realm  Of the file  Realm  Instances must be released before the delete operation can be performed. 
   Therefore, in the operating  Realm I need to add it to the instance  autoleasepool  . The following :
  autoreleasepool {
  // all  Realm  Operation operation 
  }
  */
 /// Realm  File deletion operation 
 static func deleteRealmFile() {
  let realmURL = Realm.Configuration.defaultConfiguration.fileURL!
  let realmURLs = [
   realmURL,
   realmURL.appendingPathExtension("lock"),
   realmURL.appendingPathExtension("log_a"),
   realmURL.appendingPathExtension("log_b"),
   realmURL.appendingPathExtension("note")
  ]
  let manager = FileManager.default
  for URL in realmURLs {
   do {
    try manager.removeItem(at: URL)
   } catch {
    //  Handling errors 
   }
  }
  
 }
}

conclusion