1. Shootout! Template engines for the JVM Jeroen Reijn | @jreijn | #jfall13

2. About me Architect @ Hippo Worked on web based platforms since 2001 with PHP, XSLT, JSP,Velocity and Freemarker Blogger at http://blog.jeroenreijn.com

3. Session agenda General overview Interesting template engines Benchmark project Performance results

4. Template engine? What is a Template ? What is a Template Engine ? How many Java Template Engines ? Java-Source.net : 21 Wikipedia: 17

5. Most commonly used JSP Freemarker Velocity

6. Overview

7. Selection criteria Project activity Framework support Active Community Brings added value IDE support

8. Most interesting Thymeleaf Mustache Jade Scalate

9. Thymeleaf

10. Overview Available at http://www.thymeleaf.org/ Java, DOM based template engine XML / XHTML / HTML5 Full Spring MVC integration Natural templating

11. Natural templating From Wikipedia: The template can be a document as valid as the nal result, the engine syntax doesn't break the document's structure

12. JSP in browser

13. Thymeleaf in browser

14. Variables & Loops Variables ! Loops

15. Fragments Include fragment ! Dene fragment based on th:fragment

16. {{ Mustache }}

17. Overview Available at https://mustache.github.com logic-less because there are no control statements (i.e. if, else, loops, etc) Tags are specied using {{ }} (looks like a mustache) Implemented by many languages: Java, Ruby, JavaScript, Python, Erlang, PHP, Objective- C, .NET, C++, Go, ColdFusion, Scala, etc.

18. Overview Java implementations: JMustache Mustache.java Not web specic Spring MVC integration as an 3th party add-on

19. Variables { greeting : Hello, message : World } {{greeting}} {{message}} Data Template Hello World Output

20. Sections { "repo": [ { "name": "resque" }, { "name": "hub" }, { "name": "rip" }, ] } {{#repo}}

{{name}} {{/repo}} Data Template

resque

hub

rip Output

21. Fragments base.mustache: Presentations {{#presentations}} {{> presentation}} {{/presentations}} ! presentation.mustache: {{title}}

{{startTime}}

Template

22. Jade

23. Jade Available at http://jade-lang.com Node.js Template engine Java Implementation: Jade4j Compact notation

24. Syntax

25. Result

26. Variables & Iterations Variables ! Iterations

27. Fragments

28. Overview Available at http://scalate.fusesource.org/ Scala based Template Engine (ScalaTE) Templates are compiled as Scala objects Equivalent to using JSP, JSTL, JSP EL & Tiles / Sitemesh Integration available for Spring, Play, Lift, ...

29. Template languages SSP (Scala Server Pages) SCAML (based on Rubys HAML) Mustache Jade

30. Scaml Based on HAML (HTML abstraction markup language) Integrates Scala code Well formatted markup Similar to Jade

31. Variables & Loops ! ! Fragment support is possible Inline Scala code

32. Benchmark project

33. Benchmark project Simple Spring MVC application Multiple view resolvers Page that show a list of presentations Uses page layouts / fragments Uses i18n where possible

34. Spring MVC

35. public class Presentation { private Long id; private String title; private String speakerName; private String summary; private String room; private Date startTime; private Date endTime; }

36. Project available Project will be available as open source on github. https://github.com/jreijn/spring-comparing- template-engines

37. Results!

38. Performance 0,00s 3,57s 7,14s 10,71s 14,29s 17,86s 21,43s 25,00s Total time taken for 25.000 requests (less is better) Thymeleaf - v2.1.0 Jade4j - v0.3.17 Scalate - v1.6.1 Mustache - v1.8 Freemarker - v2.3.19 Velocity - v1.7 JSP - 2.1

39. Findings Thymeleaf uses more memory and was slower then the commonly used Scalate was a lot slower due to the layout mechanism. More than 100 seconds for 25.000 requests. Mustache performs really well!

40. Tips If you want designers to own your templates consider Mustache or Thymeleaf If you want developers to own your templates: If you want to generate HTML / XML and DRY? => Jade otherwise: JSP, Freemarker, etc

41. Thank you! Questions? @jreijn j.reijn@onehippo.com