Complete

Complete is a general purpose completion handler system that is mobile compatible with gomobile. Clients can follow the Completionable interface to write their own completion handlers in their native language which will be executed upon completion in Go.

Complete also provides a generic Result struct that can hold any kind of Go data structure, even if it is not supported by the native language. It's up to the Go library or program to provide type assertion methods to convert the generic Result object into its actual type.

Usage

iOS

Because functions cannot be passed directly to go, each target language must implement their own completion handler class that implements the complete.Completionable interface/protocol.

Here is an example completion handler in Swift:

class CompletionHandler: GoCompleteCompletionableProtocol {
    
    var success: ((result: GoCompleteResult!) -> Void)!
    var failure: ((msg: String!, error: NSError!) -> Void)!

    @objc func onSuccess(p0: GoCompleteResult!) {
        self.success(result: p0)
    }
    
    @objc func onFailure(p0: String!, p1: NSError!) {
        self.failure(msg: p0, error: p1)
    }
}

func onSuccess(success: ((result: GoCompleteResult!) -> Void)!, failure: ((msg: String!, error: NSError!) -> Void)!) -> CompletionHandler {
    let handler = CompletionHandler()
    handler.success = success
    handler.failure = failure
    return handler
}

Login example

Here is an example in Swift of logging inwith a completion handler:

        // Login
        Login("picard", "123456", false, onSuccess({ (result) in
            print("Logged in!")
            }, failure: { (msg, error) in
                print("Failed to log in: \(msg)")
        }))

Android

Here is an example completion handler in Java. There may be better way to implement your completion handler:

public class CompletionHandler implements Handlers.Completionable {

    private Success success;
    private Failure failure;

    public void OnSuccess(Result result) {
        this.success.call(result);
    }
    public void OnFailure(String error) {
        this.failure.call(error);
    }

    public static CompletionHandler onSuccess(Success success, Failure failure) {
        CompletionHandler handler = new CompletionHandler();
        handler.success = success;
        handler.failure = failure;

        return handler;
    }
}

// Used for calling the success handler.
interface Success {
    void call(Result result);
}

// Used for calling the failure handler.
interface Failure {
    void call(String error);
}

Login example

Here is an example in Java of logging in with a completion handler:

// Login
Login("picard", "123456", false,
    CompletionHandler.onSuccess(
        new Success() {
            @Override
            public void call(Complete.Result result) {
                System.out.println("Logged in!");
            }
        },
        new Failure() {
            @Override
            public void call(String error) {
                System.out.println(error);
            }
        }
    )
);