Completable Future java 8 Features with example
- 2. What is it used for? • Perform possible asynchronous(non-blocking) computation and trigger dependent computations which could also be asynchronous.
- 3. Basics of Asynchronous Operation main thread separate thread Task ❌ Runnable
- 4. Basics of Asynchronous Operation main thread separate thread Task Callable
- 5. Runnable (vs) Callable • Runnable (vs) Callable comes into point when we are using Executer framework. • ExecutorService is a subinterface of Executor, which accepts both Runnable and Callable tasks. • Earlier Multi-Threading can be achieved using Interface Runnable(Since 1.0), but here the problem is after completing the thread task we are unable to collect the Threads information. In-order to collect the data we may use Static fields.
- 6. Working with Callable and Futures • Lets Check small code example
- 7. Visualize The Callable And Future Example thread-pool Task 2 Task 1 Task 3 … Blocking queue t0 t1 t2 t3 …. t10 Fetch next task From queue Execute it main thread Future<Integer> future = service.submit(new Task()); placeholder Once result is ready 3 Set value of placeholder
- 8. Visualize The Callable And Future Example thread-pool Task 2 Task 1 Task 3 … Blocking queue t0 t1 t2 t3 …. t10 Fetch next task From queue Execute it main thread Future<Integer> future = service.submit(new Task()); placeholder Once result is ready 3 Set value of placeholder future.get() blcoked runnable Run dependent taks
- 9. There Is A Problem thread-pool Task 2 Task 1 Task 3 … Blocking queue t0 t1 t2 t3 …. t10 Fetch next task From queue Execute it main thread for 1..4 service.submit(new Task()) Once result is ready future.get() blcoked runnable Run dependent taks 7 5 1 7 5
- 10. Dependent tasks Fetch Order Enrich Order payment Dispatch Send Email For All orders
- 11. Independent Flows Fetch Order Enrich Order payment Dispatch Send Email Fetch Order Enrich Order payment Dispatch Send Email Fetch Order Enrich Order payment Dispatch Send Email Independent Flow ……………….