There are plenty of use cases when mBaaS-powered applications must use a centralized mechanism for incrementing or decrementing a value. There are several approaches for maintaining a counter – some apps use a database, others keep it in the server-side business logic (Cloud Code).
Backendless offers a specialized API for working with atomic counters. The API is cross-platform – any number of different clients (including REST) can work with the same counter and update it concurrently. Every counter in Backendless has a name, which is assigned by the client application. The sample below demonstrates the API for incrementing and retrieving the value of a counter.
IAtomiccounter = Backendless.Counters.of("my counter"); counter.incrementAndGet(new AsyncCallback () { @Override public void handleResponse(Long response) { Log.i( TAG, "Counter value: " + response ); } @Override public void handleFault(BackendlessFault fault) { Log.e( TAG, "Server reported an error: " + fault.getMessage() ); } });
val counter = Backendless.Counters.of("my counter")
counter.incrementAndGet(object : AsyncCallback {
override fun handleResponse(response: Int?) {
Log.i(TAG, "Counter value: " + response!!)
}
override fun handleFault(fault: BackendlessFault) {
Log.e(TAG, "Server reported an error: " + fault.message)
}
})
id counter = [Backendless.shared.counters ofCounterName:@"my counter"];
[counter incrementAndGetWithResponseHandler:^(NSInteger counterValue) {
NSLog(@"Counter value - %li", (long)counterValue);
} errorHandler:^(Fault *fault) {
NSLog(@"Error: %@", fault.message);
}];
let counter = Backendless.shared.counters.of(counterName: "my counter")
counter.incrementAndGet(responseHandler: { counterValue in
print("Counter value - \(counterValue)")
}, errorHandler: { fault in
print("Error: \(fault.message ?? "")")
})
const counter = Backendless.Counters.of('my counter')
counter.incrementAndGet()
.then(counterValue => {
console.log(`Counter value - ${ counterValue }`)
})
.catch(error => {
console.error(`Server reported an error - ${ error.message }`)
})
IAtomic counter = Backendless.counters.of("my counter");
counter.incrementAndGet().then((value) {
print("Counter value - $value");
});
The API is very easy to use and provides several other features like decrementing a value, performing a conditional update, retrieving the current value, and resetting a counter.