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FWEugene/NSManagedObject+Extension.swift

Last active August 5, 2019 11:02
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  1. FWEugene renamed this gist Apr 10, 2018. 1 changed file with 0 additions and 0 deletions.
    0 gistfile1.txt → NSManagedObject+Extension.swift
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  2. FWEugene created this gist Apr 10, 2018.
    74 changes: 74 additions & 0 deletions gistfile1.txt
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,74 @@
    //MARK: NSManagedObject Extension
    public extension NSManagedObject {

    public static func findOrCreate<T: NSManagedObject>(with keyedValues: [String: Any], context: NSManagedObjectContext) -> T {
    let object: T? = self.findFirst(with: keyedValues, context: context)
    if let found = object {
    return found
    } else {
    var new: T!
    context.performAndWait {
    new = T.init(context: context)
    new.setValuesForKeys(keyedValues)
    }
    return new
    }
    }

    public static func createEntity<T: NSManagedObject>(context: NSManagedObjectContext) -> T {
    var new: T!
    context.performAndWait {
    new = T.init(context: context)
    }
    return new
    }

    public static func findFirst<T: NSManagedObject>(context: NSManagedObjectContext) -> T? {
    let result = T.findFirst(with: nil, context: context)
    return result as? T
    }


    public static func findFirst<T: NSManagedObject>(with keyedValues: [String: Any]?, context: NSManagedObjectContext) -> T? {
    var result: NSFetchRequestResult?
    context.performAndWait {
    let fetchRequest = self.fetchRequest()
    fetchRequest.predicate = keyedValues?.predicate
    let results = try? fetchRequest.execute()
    if let results = results, results.count > 0 {
    result = results.first
    }
    }

    return result as? T
    }


    public static func findAll<T: NSManagedObject>(with keyedValues: [String: Any]?, context: NSManagedObjectContext) -> [T]? {
    var results: [NSFetchRequestResult]?
    context.performAndWait {
    let fetchRequest = self.fetchRequest()
    fetchRequest.predicate = keyedValues?.predicate
    if let result = try? fetchRequest.execute() {
    results = result
    }
    }

    return results as? [T]
    }
    }

    fileprivate extension Sequence where Iterator.Element == (key: String, value: Any) {
    var predicate: NSPredicate {
    var predicateFormat: String = ""
    var values: [Any] = []
    for (key, value) in self {
    predicateFormat += "\(key) == %@ AND "
    values.append(value)
    }
    let index = predicateFormat.index(predicateFormat.endIndex, offsetBy: -5)
    predicateFormat = String(predicateFormat[..<index])
    let predicate = NSPredicate(format: predicateFormat, argumentArray: values)
    return predicate
    }
    }