GWT Introduction and Overview - SV Code Camp 09
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This document summarizes a presentation about Google Web Toolkit (GWT). It discusses how GWT allows developers to write code in Java and compile it to optimized JavaScript. GWT handles cross-browser compatibility issues and improves developer productivity through features like Java debugging and code splitting. It also improves end user performance through techniques like deferred binding, image sprites, and compiler optimizations that minimize code size and roundtrip times.
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GWT Introduction and Overview - SV Code Camp 09
- 1. 1 Google Web Toolkit Introduction & Overview Introduction & Overview Fred Sauer Developer Advocate fredsa@google.com SV Code Camp Oct 4, 2009
- 2. 2 Agenda Introduction Selecting a language Feature tour Developer productivity Need for speed Compiler magic Q&A
- 3. 3 Google Web Toolkit Write Core Java APIs Widgets Libraries Java IDEs Debug JVM Debugging Development Mode A real browser Developer Productivity Optimize GWT Compiler Image Bundle (Sprites) CSS Magic End User Performance Run Desktop Mobile Online/Offline Gadgets
- 4. 4 May 2006 GWT 1.0 Launch at JavaOne Aug 2008 GWT 1.5 Java 5 language support Apr 2009 GWT 1.7 Dedicated IE8 support Fall 2009 GWT 2.0 LOTS of interesting stuff 3+ years in review
- 5. 5 Mission statement "GWT's mission is to radically improve the web experience for users by enabling developers to use existing Java tools to build no-compromise AJAX for any modern browser."
- 6. 6 Focus Productivity for developers Language, IDEs, tools, libraries People, ecosystem Performance for your users 'Perfect' caching Whole program optimization Better than practical hand written code
- 7. 7 No plugins required VML Flash Silverlight
- 8. 8 What we don't want
- 9. 9 GWT Browser-Proofs Your JavaScript Code... IE Firefox Safari Chrome Opera
- 10. 10 Deferred Binding 14800 ms4836 ms1997 ms7148 msDOM manipulation 2469 ms1520 ms918 ms2477 msinnerText=... -1386 ms908 ms-textContent=... 4078 ms2053 ms1276 ms2876 msTypical portable setInnerText() IEOperaWebkit (Safari)Firefox Improvement 39%32%29%14%
- 11. 11 A More Powerful Web, Made Easier
- 12. 12 Eating our own dogfood 12
- 14. 14 Rich ecosystem of tools and libraries + + =
- 15. 15 Code completion and javadoc
- 16. 16 Can you find the bug? Hint: JavaScript is a dynamic language
- 17. 17 Java is a static language Catch errors at compile time
- 18. 18 Feature tour
- 20. 20 More than just a compiler
- 21. 21 Sprites for free 20,558 bytes 6,824 bytes 11 separate images 1 bundled image
- 23. 23 Roundtrips are deadly 1 round trip for TCP connection setup (1 round trip for HTTP redirect?) 1 round trip for each HTTP request $ ping ohare.comPING ohare.com (70.142.247.22): 56 data bytes64 bytes from 70.142.247.22: icmp_seq=0 ttl=113 time=54.689 ms64 bytes from 70.142.247.22: icmp_seq=1 ttl=113 time=55.500 ms64 bytes from 70.142.247.22: icmp_seq=2 ttl=113 time=54.728 ms $ ping ohare.comPING ohare.com (70.142.247.22): 56 data bytes64 bytes from 70.142.247.22: icmp_seq=0 ttl=113 time=54.689 ms64 bytes from 70.142.247.22: icmp_seq=1 ttl=113 time=55.500 ms64 bytes from 70.142.247.22: icmp_seq=2 ttl=113 time=54.728 ms
- 24. 24 Reducing round trip time Use HTTP Expires and Cache-Control headers Use GWT 'Perfect Caching' Cache 'forever' - your entire app and all its resources Bundle, bundle, bundle Enable HTTP Pipelining Use multiple hostnames Defeat browser's two connection limit Watch out for DNS lookup overhead though
- 25. 25 Know your HTTP Headers <!-- See RFC 2616. Here's an example: Expires: Thu, 02 Sep 2010 03:21:55 GMT Cache-Control: public, max-age=31536000 --> <Files *.cache.*> ExpiresDefault "now plus 1 year" </Files> <Files *.nocache.*> ExpiresDefault "access" </Files>
- 28. 28 RTL, I18N, L10N, A11Y
- 29. 29 Widget Libraries • GWT (http://code.google.com/webtoolkit/) • Incubator (http://code.google.com/p/google-web-toolkit-incubator/) • Smart GWT (http://code.google.com/p/smartgwt/) • GWT-Ext (http://code.google.com/p/gwt-ext/) • Vaadin (IT Mill Toolkit) (http://vaadin.com/) • GWT mosaic (http://code.google.com/p/gwt-mosaic/) • Ext GWT (http://extjs.com/products/gxt/) • Advanced GWT Components (http://advanced-gwt.sourceforge.net/)
- 30. 30 GUI Editing
- 31. 31 Simple, Powerful RPCs interface SpellService extends RemoteService { /** * Checks spelling and suggests * alternatives. * @param the word to check * @return the list of alternatives */ String[] suggest(String word); }
- 32. 32 Shameless plugs (gwt-dnd, gwt-log, gwt- voices)
- 34. 34 GWT 2.0 operating modes Development Mode (Hosted Mode) All about productivity Java + JavaScript Now in any supported browser Production Mode (Web Mode) All about performance Compiled, Pure JavaScript
- 35. 35 Development Mode (Hosted Mode) JVM debugging Server & Client code in the same IDE Step in / over / out Introspect & modify variables Hot swap code (ignore the IDE warning!) NOT TRUE
- 36. 36 Java Virtu al Mac hine Development Mode Code Server Web Server Duke, the Java mascot Copyright © Sun Microsystems Inc., all rights reserved.
- 37. 37 Google Plugin for Eclipse
- 38. 38 Eclipse plugin highlights Extensive JSNI support RPC sync/async quick fixes Launch configurations GWT JUnit tests Contributor SDKs (gwt-user, gwt-dev-<platform>) Development Mode (GWT 2.0) Hosted Mode (GWT 1.7) Constantly improving; check back often
- 39. 39 GWT Debugging in the browser
- 41. 41 Speed matters perceived as instantaneous. maintains the feeling that a single task is being carried out. limit for keeping user’s attention. 0.1 seconds 1 second 10 seconds
- 42. 42 Another reason speed matters 2. UI Changes 3. User Learns 1. User Action Performance for your
- 43. 43 GWT Helps Apps Startup More Quickly 26-Nov 29-Apr 18-Jun 28-Jul 12-Sep 27-Oct 24-Dec 16-Mar SizeofInitialJavaScriptDownload(KB) 375 750 1125 1500 0 7x Decrease In Initial Download Size with runAsync() 1400 KB 200 KB
- 44. 44 Developer guided code splitting
- 45. 45 Developer guided code splitting
- 46. 46 Manual code splitting - Don't try this at home 46
- 47. 47 Developer guided code splitting GWT.runAsync(new RunAsyncCallback() { public void onSuccess() { … } public void onFailure(Throwable caught) { … } });
- 48. 48 Story of Your Compile (SOYC) -C
- 50. 52 GWT quote to remember “The fastest code is that which does not run.” Joel Webber GWT co-creator
- 51. 53 Conventional and non-conventional Java transformations Dead-code elimination Method inlining Constant folding & propagation JavaScript transformations (gzip motivated) Method reordering Argument renaming
- 52. 54 EXPERIMENTAL arguments you should know // Don't care what Class#getName() returns? -XdisableClassMetadata 5% - 10% script reduction Showcase metadata before Showcase metadata after
- 53. 55 EXPERIMENTAL arguments you should know // In a real-world (very large) Google app... // 1% script size reduction // 10% faster in performance-sensitive code -XdisableCastChecking try { ((Quacker) animal).quack(); } catch (ClassCastException c) { Window.alert("Found a non-quacker"); }
- 54. 83 Thank you Read more http://code.google.com/webtoolkit/ Contact info Fred Sauer Developer Advocate fredsa@google.com Questions?
Editor's Notes
- quick survey Raise your hand if you&apos;ve never written a web app using GWT …your organization maintains multiple (&gt;1) GWT apps …uses GWT for all new web apps We have a lot to cover, so let&apos;s begin
- Hope: you&apos;ve read GWT mission statement Hope: agree that we must FOCUS ON THE USER experience Part of that mission means making you, the developer, more productive
- In other words, GWT is all about… PRODUCTIVITY FOR DEVELOPERS LIKE YOU AND PERFORMANCE FOR YOUR USERS
- Google Web Toolkit 101
- OUR generators, more importantly YOUR generators
- I&apos;d like to take a moment to talk about a widely misunderstood problem. The problem is of course: WHY IS OUR WEB SITE SO SLOOOOOOOOOW? &lt;click through&gt; If HTML + CSS + JavaScript + Images = 40 files, that&apos;s 50ms*40=2s Last night I pinged a few servers in Sydney; 380ms * 40 = 15s!!!
- GWT produces two classes of files: cache/nocache - *cache* =&gt; cache forever; new versions receive new file names - *nocache* =&gt; must-revalidate Raise your hand if your web server set Expires/Cache-Control headers So how do we create those perfectly cacheable *cache* files?
- When you&apos;re building real apps you need certain things to &quot;just work&quot; Constants, Messages, ConstantsWithLookup, Dictionary, Localizable, DateTimeFormat, NumberFormat
- That&apos;s the productivity, performance and speed pitch Now, let&apos;s get to know our toolkit in more detail
- A very useful tool: - understand why your JavaScript output isn&apos;t quite as small (yet) as it could be - why initial download is large
- We already covered -style PRETTY and -draftCompile for DEVELOPMENT. Hopefully in DEVELOPMENT you also are building just ONE PERMUTATION (i.e. one browser, one language, one logging level) - If not (or for PRODUCTION) use -localWorkers=#cores
- Now for something different. Here&apos;s a simple JavsScript object in JSON format - {} identify JavaScript objects, [] identify arrays, : for name/value pairs JSON is great - transfer data between client and server OR between servers - Subset of ECMA script so it can be parsed or eval()&apos;d by the browser
- In JavaScript you have a couple of options 1. Write the whole thing out every time; brittle w.r.t. changes 2. Introduce function overhead Wouldn&apos;t it be great if we could have our cake and eat it too? WE CAN!
- If you&apos;re using com.google.gwt.json.JSON library, STOP Use JSO Types instead -You keep the abstractions that make you productive -Your user sees none of that code; only the benefits GREAT for federating/integrating with other systems via web hooks or RESTful interfaces
- ImageBundles are really easy to create - Declare an interface with a method for each image - That&apos;s it!
- We can of course bundle other resources as well Remember: bundle, bundle, bundle
- RFC 2397 data: URLs This cursor data: URL can be injected into your injected stylesheet at compile time - You get the convenience of a separate *.cur file - The user either gets a forever cacheable strongly named URL or an inline data: resource - YOU BOTH WIN
- Locale sensitive names so different languages can have different images Your getWidth()/getHeight() methods automatically adjust
- &lt;set-configuration-property name=&quot;CssResource.obfuscationPrefix&quot; value=&quot;foo&quot; /&gt; &lt;set-configuration-property name=&quot;CssResource.obfuscationPrefix&quot; value=&quot;foo&quot; /&gt;
- How many of you are interested in gadgets? &lt;MAYBE SKIP SECTION?&gt; GWT makes it really easy to create them without having to resort to hand written JavaScript
- - Logging code is partially/completely compiled out in production - Mobile clients log to server - UncaughtExceptionHandler included
- Add or improve stack traces where browsers are lacking
- compiler.emulatedStack does add overhead (not for PRODUCTION) - You can just turn on recordLineNumbers (less overhead) - You can already get original method names from the symbol maps
- This stack trace came from 100% compiled JavaScript - UNKNOWN indicates this is browser land, not your JVM - short, two-letter method names shows OBFUSCATED output - Original Java class/method names injected into source - Copy/paste into your IDE stacktrace console and they are hyperlinked!