simple Event-Aggregator using ReactiveCocoa

EventAggregator.h

#import <Foundation/Foundation.h>
#import <ReactiveCocoa/ReactiveCocoa.h>

@interface EventAggregator : NSObject {
    RACSubject *subject;
    RACSignal *stream;
}
- (void) subscribe:(Class) type :(void (^)(id event))handler;
- (void) send:(id)event;
@end

EventAggregator.m

#import "EventAggregator.h"

@implementation EventAggregator

- (id) init
{
    self = [super init];
    subject = [RACSubject subject];
    RACMulticastConnection *connection = [subject publish];
    stream = connection.signal;
    [connection connect];
    return self;
}

-(void) subscribe:(Class)type :(void (^)(id))handler{
    RACSignal *filtered = [stream filter:^BOOL(id value) {
        return [value isMemberOfClass:type];
    }];
    
    [filtered subscribeNext:handler];
}

- (void) send:(id)event
{
    [subject sendNext:event];
}
@end

MySampleAppDelegate.m

@implementation MySampleAppDelegate
+(EventAggregator*) ea
{
    static EventAggregator* eventAggregator = nil;
    
    if (eventAggregator == nil)
    {
        eventAggregator = [[EventAggregator alloc]init];
    }
    
    return eventAggregator;
}

SampleViewController.m

void (^DateEventHandler)(DateEvent*) = ^(DateEvent *event){
    NSLog(@"Date Event :%@", event.date);
};

- (void)viewDidLoad
{
    [MySampleAppDelegate.ea subscribe:[DateEvent class] :DateEventHandler];
    [MySampleAppDelegate.ea subscribe:[NameEvent class] :^(NameEvent *event) { NSLog(@"Name Event :%@", event.name); }];
    
    
    [MySampleAppDelegate.ea send: [[DateEvent alloc]initWithName:[NSDate new]] ]; //send DateEvent
    [MySampleAppDelegate.ea send: [[NameEvent alloc]initWithName:@"Demo Event"] ]; //send NameEvent
    [MySampleAppDelegate.ea send: [[NoneEvent alloc]init] ]; //sample of non attached handler
    [MySampleAppDelegate.ea send: [[DateEvent alloc]initWithName:[NSDate new]] ];
    [MySampleAppDelegate.ea send: [[NameEvent alloc]initWithName:@"Demo Event 2"] ];
}