querying

HardcoreData/NSManagedObjectContext+Querying.swift

@@ -0,0 +1,157 @@
+//
+//  NSManagedObjectContext+Querying.swift
+//  HardcoreData
+//
+//  Copyright (c) 2015 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+import Foundation
+import CoreData
+
+
+extension NSManagedObjectContext {
+    
+    public func fetchOne<T: NSManagedObject>(entity: T.Type, _ queryClauses: FetchClause...) -> T? {
+        
+        return self.fetchOne(entity, queryClauses)
+    }
+    
+    public func fetchOne<T: NSManagedObject>(entity: T.Type, _ queryClauses: [FetchClause]) -> T? {
+        
+        let fetchRequest = NSFetchRequest()
+        fetchRequest.entity = NSEntityDescription.entityForName(
+            entity.entityName,
+            inManagedObjectContext: self)
+        fetchRequest.fetchLimit = 1
+        fetchRequest.resultType = .ManagedObjectResultType
+        
+        for clause in queryClauses {
+            
+            clause.applyToFetchRequest(fetchRequest)
+        }
+        
+        var fetchResults: [T]?
+        var error: NSError?
+        self.performBlockAndWait {
+            
+            fetchResults = self.executeFetchRequest(fetchRequest, error: &error) as? [T]
+        }
+        if fetchResults == nil {
+            
+            HardcoreData.handleError(error!, "Failed executing fetch request.")
+            return nil
+        }
+        
+        return fetchResults?.first
+    }
+    
+    public func fetchAll<T: NSManagedObject>(entity: T.Type, _ queryClauses: FetchClause...) -> [T]? {
+        
+        return self.fetchAll(entity, queryClauses)
+    }
+    
+    public func fetchAll<T: NSManagedObject>(entity: T.Type, _ queryClauses: [FetchClause]) -> [T]? {
+        
+        let fetchRequest = NSFetchRequest()
+        fetchRequest.entity = NSEntityDescription.entityForName(
+            entity.entityName,
+            inManagedObjectContext: self)
+        fetchRequest.fetchLimit = 0
+        fetchRequest.resultType = .ManagedObjectResultType
+        
+        for clause in queryClauses {
+            
+            clause.applyToFetchRequest(fetchRequest)
+        }
+        
+        var fetchResults: [T]?
+        var error: NSError?
+        self.performBlockAndWait {
+            
+            fetchResults = self.executeFetchRequest(fetchRequest, error: &error) as? [T]
+        }
+        if fetchResults == nil {
+            
+            HardcoreData.handleError(error!, "Failed executing fetch request.")
+            return nil
+        }
+        
+        return fetchResults
+    }
+    
+    public func queryCount<T: NSManagedObject>(entity: T.Type, _ queryClauses: FetchClause...) -> Int {
+    
+        return self.queryCount(entity, queryClauses)
+    }
+    
+    public func queryCount<T: NSManagedObject>(entity: T.Type, _ queryClauses: [FetchClause]) -> Int {
+        
+        let fetchRequest = NSFetchRequest()
+        fetchRequest.entity = NSEntityDescription.entityForName(
+            entity.entityName,
+            inManagedObjectContext: self)
+        
+        for clause in queryClauses {
+            
+            clause.applyToFetchRequest(fetchRequest)
+        }
+        
+        var count = 0
+        var error: NSError?
+        self.performBlockAndWait {
+            
+            count = self.countForFetchRequest(fetchRequest, error: &error)
+        }
+        if count == NSNotFound {
+            
+            HardcoreData.handleError(error!, "Failed executing fetch request.")
+            return 0
+        }
+        
+        return count
+    }
+    
+    
+//    public func queryCount<T: NSManagedObject, U: IntegerType>(entity: T.Type, _ queryClauses: [FetchClause]) -> U? {
+//        
+////        let expressionDescription = NSExpressionDescription()
+////        expressionDescription.name = "queryCount"
+////        expressionDescription.expressionResultType = .Integer32AttributeType
+////        expressionDescription.expression = NSExpression(
+////            forFunction: "min:",
+////            arguments: [NSExpression(forKeyPath: attribute)])
+//        
+//        let request = NSFetchRequest(entityName: entity.entityName)
+//        request.resultType = .DictionaryResultType
+//        request.predicate = predicate
+//        request.propertiesToFetch = [expressionDescription]
+//        
+//        var error: NSError?
+//        let results = NSManagedObjectContext.context()?.executeFetchRequest(request, error: &error)
+//        if results == nil {
+//            
+//            JEDumpAlert(error, "error")
+//            return nil
+//        }
+//        
+//        return (results?.first as? [String: NSDate])?[expressionDescription.name]
+//    }
+}