35 lines
1.3 KiB
Markdown
35 lines
1.3 KiB
Markdown
---
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layout: pattern
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title: Async Method Invocation
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folder: async-method-invocation
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permalink: /patterns/async-method-invocation/
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categories: Concurrency
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tags:
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- Java
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- Difficulty-Intermediate
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- Functional
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- Reactive
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---
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## Intent
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Asynchronous method invocation is pattern where the calling thread
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is not blocked while waiting results of tasks. The pattern provides parallel
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processing of multiple independent tasks and retrieving the results via
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callbacks or waiting until everything is done.
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# Class diagram
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## Applicability
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Use async method invocation pattern when
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* you have multiple independent tasks that can run in parallel
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* you need to improve the performance of a group of sequential tasks
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* you have limited amount of processing capacity or long running tasks and the
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caller should not wait the tasks to be ready
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## Real world examples
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* [FutureTask](http://docs.oracle.com/javase/8/docs/api/java/util/concurrent/FutureTask.html), [CompletableFuture](https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CompletableFuture.html) and [ExecutorService](http://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ExecutorService.html) (Java)
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* [Task-based Asynchronous Pattern](https://msdn.microsoft.com/en-us/library/hh873175.aspx) (.NET)
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