The goal of this library is to help manage NSOperationQueue dependencies. This allows you to create a dependency tree explicitly.
Here is an example usage
// initialize the graph
NDSOperationGraph *graph = [[NDSOperationGraph alloc] init];
// Declare dependencies
[self.graph operationOfType:[NDSOperationBar class] dependsOn:[NDSOperationFoo class]];
[self.graph operationOfType:[NDSOperationZap class] dependsOn:[NDSOperationBar class]];
// setup success and failure blocks
[self.graph setSuccessBlock:^{
NSLog(@"success finished");
}];
[self.graph setFailureBlock:^(NDSGraphOperationBase *operation, NSError *error, id errorObject){
NSLog(@"errorObject %@", errorObject);
}];
// add operations
NDSOperationZap *zap = [[NDSOperationZap alloc] init];
NDSOperationFoo *foo1 = [[NDSOperationFoo alloc] init];
NDSOperationFoo *foo2 = [[NDSOperationFoo alloc] init];
NDSOperationFoo *foo3 = [[NDSOperationFoo alloc] init];
[self.graph addOperations:@[zap, foo1, foo2, foo3]];
// start it on whatever queue you want
[self.graph startOperationsOnOperationQueue:[NSOperationQueue mainQueue]];Your operations must subclass NDSGraphOperationBase This is to stop operation if any of the operations fail.
In your subclass you are responsible for implementing operationWork
You are responsible for calling finishSuccessWith: or finishFailureWith:object: depending on if it is a success or failure.
You can have any number of levels of dependencies. Dependencies are transitive. This mean if A depends on B and B depends on C. Then A depends on C. If you only have operations of A and C, any A operations won't execute until all C operations succeed.
See the the Example for detailed usage
NDSOperationGraph is available through CocoaPods, to install it simply add the following line to your Podfile:
pod "NDSOperationGraph"
Nicholas Schlueter, schlueter@gmail.com
NDSOperationGraph is available under the MIT license. See the LICENSE file for more info.