How to get object from mono without blocking

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To get an object from Mono without blocking, you can make use of asynchronous operations and reactive programming techniques. Mono is a reactive type in the Spring Framework that represents a Publisher with a single result.

One way to handle obtaining an object from a Mono without blocking is by using the subscribe() method with a callback function. The callback function will be invoked when the Mono emits the object. Here’s an example:


Mono<String> mono = Mono.just("Hello World");

mono.subscribe(result -> {
   System.out.println(result); // Output: Hello World
});

In the example above, we create a Mono that emits a String value “Hello World”. We then subscribe to the Mono and provide a lambda function that receives the result. The lambda function will be invoked once the Mono emits the value, allowing us to process the object without blocking.

Another approach is to use reactive operators like flatMap(), map(), or filter() to transform the emitted object or perform additional operations. These operators return another Mono, allowing you to chain multiple operations together. Here’s an example using flatMap():


Mono<Integer> mono = Mono.just(5);

mono.flatMap(value -> {
   return Mono.just(value * 2); // Perform an operation on the emitted value
})
.subscribe(result -> {
   System.out.println(result); // Output: 10
});

In this example, we start with a Mono that emits an Integer value of 5. We then use flatMap() to perform an operation on the emitted value, multiplying it by 2. The resulting Mono emits the transformed value of 10, which we print in the subscribe() callback.

Using these techniques, you can work with objects emitted by Mono without blocking, allowing for efficient and responsive programming.

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