Deep dive reactive java (DevoxxPl)
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This document discusses reactive and asynchronous programming. It begins with a brief history, noting that these concepts have been rediscovered numerous times. It then discusses how asynchronous push communication differs from synchronous pull communication. The document provides an example of decomposing synchronous code into individual asynchronous operations. It notes that error handling, timeouts, monitoring, logging, back pressure, and parallelism are missing from the example. Finally, it states that reactive programming concepts are now available in many languages and frameworks.
Deep dive reactive java (DevoxxPl)
- 1. T O M A S Z K O W A L C Z E W S K I
- 2. Agenda • A little bit of history • Challenges before us • A few words about API • Code!
- 3. Reactive, asynchronous • People have been doing it for years • (Re)invented time and again by big companies and/or in high performance products –Donald Knuth “The idea that people knew a thing or two in the 70s is strange to a lot of young programmers”
- 4. Reactive, asynchronous • People have been doing it for years • (Re)invented time and again by big companies and/or in high performance products • Now every company may need to operate at that scale • As users demand more and faster we need tools to do it right
- 5. It started in Microsoft
- 6. Brought to you by Erik Meijer & co.
- 7. Synchronous pull communication Client Server Request Response Processing Network latency
- 9. Asynchronous push t subscribe onNext* onCompleted | onError unsubscribe
- 10. Synchronous design List<String> tweets = client.getNextTweets(); List<Tweet> validTweets = Lists.newArrayList(); for (String jsonTweet : tweets) { Tweet tweet = gson.fromJson(jsonTweet, Tweet.class); Image image; image = download(tweet.getUser().getProfileImage()); Tweet.setImage(image); if (tweet.isValidTweet()) { validTweets.add(tweet); } }
- 11. Decomposing individual operations List<String> tweets = client.getNextTweets(); List<Tweet> validTweets = Lists.newArrayList(); for (String jsonTweet : tweets) { Tweet tweet = gson.fromJson(jsonTweet, Tweet.class); Image image; image = download(tweet.getUser().getProfileImage()); Tweet.setImage(image); if (tweet.isValidTweet()) { validTweets.add(tweet); } }
- 12. Decomposing individual operations List<String> tweets = client.getNextTweets(); List<Tweet> validTweets = Lists.newArrayList(); for (String jsonTweet : tweets) { Tweet tweet = gson.fromJson(jsonTweet, Tweet.class); Image image; image = download(tweet.getUser().getProfileImage()); Tweet.setImage(image); if (tweet.isValidTweet()) { validTweets.add(tweet); } }
- 13. Decomposing individual operations List<String> tweets = client.getNextTweets(); List<Tweet> validTweets = Lists.newArrayList(); for (String jsonTweet : tweets) { Tweet tweet = gson.fromJson(jsonTweet, Tweet.class); Image image; image = download(tweet.getUser().getProfileImage()); Tweet.setImage(image); if (tweet.isValidTweet()) { validTweets.add(tweet); } }
- 14. Decomposing individual operations List<String> tweets = client.getNextTweets(); List<Tweet> validTweets = Lists.newArrayList(); for (String jsonTweet : tweets) { Tweet tweet = gson.fromJson(jsonTweet, Tweet.class); Image image; image = download(tweet.getUser().getProfileImage()); Tweet.setImage(image); if (tweet.isValidTweet()) { validTweets.add(tweet); } }
- 15. What is missing? List<String> tweets = client.getNextTweets(); List<Tweet> validTweets = Lists.newArrayList(); for (String jsonTweet : tweets) { Tweet tweet = gson.fromJson(jsonTweet, Tweet.class); Image image; image = download(tweet.getUser().getProfileImage()); Tweet.setImage(image); if (tweet.isValidTweet()) { validTweets.add(tweet); } } Error handling Timeouts Monitoring Logging Back pressure Parallelism
- 17. Available in a language or framework near you
- 19. Credits • Cat picture taken from http://www.teckler.com/en/ Rapunzel