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java . blogs

This blog post, written by Mike Cannon-Brookes in June 2003, provides an overview of Java blogs, including their definition, typical components, reasons for reading and writing, and the use of RSS syndication. It also discusses popular blog software and features an introduction to javablogs.com, a web aggregator for Java-focused weblogs.

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java . blogs

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  1. java.blogs “The movement, the site, the technology” Prepared by Mike Cannon-Brookes - June, 2003 mike@atlassian.com - http://www.atlassian.com

  2. Agenda • Blogging & Java • What is java.blogs? • Technology behind javablogs.com

  3. What is a weblog? • “News site” written by one person • Online, chronological journal • Personal list of thoughts, links etc • Newest entries at the top of the page • Usually has an RSS version • Hard to categorize, easier to show you an example

  4. Typical Blog Pieces Ugly Author Pic Silly Title Posts

  5. Posts Nav Search Blog Roll About

  6. Why read blogs? • Get a personal view point • Bloggers usually discuss latest content / ideas • In the Java world, often a good source of solutions and personal experience • Example: commons-logging & log4j • Comparison: best feature on Amazon? • book reviews!

  7. Why write a blog? • Everyone has their own reasons • A place for personal expression • Share your thoughts, wisdom • Feel part of a community • Rant / rave / vent / discuss • BileBlog perfect example

  8. RSS • Really Simple Syndication? • Rich Site Summary? • RSS is the “protocol” of the syndication world • An XML format representing a list of links • Used to syndicate weblogs in a machine readable format • It is a very simple format…

  9. RSS Example <rss> <channel> <title>rebelutionary</title> <link>http://blogs.atlassian.com/rebelutionary/</link> <description>Mike Cannon-Brookes on J2EE, Java, software development, bug tracking, Atlassian, JIRA and whatever comes to mind.</description> <item> <title>The BileBlog is painfully accurate</title> <link>http://blogs.atlassian.com/rebelutionary/archives/000166.html</link> <description>Let me start by saying …</description> </item> <item> <title>Two Weeks Left to TSS </title> <link>http://blogs.atlassian.com/rebelutionary/archives/000165.html</link> <description>Less than two weeks left until TSS Symposium... </description> </item> . . . </channel> </rss>

  10. Blog Syndication Blog 2 Blog 1 Blog 3 RSS(XML) HTML RSS(XML) HTML News Aggregator Reader

  11. News Aggregators • Software to aggregate news from your personal list of favourite sites. • Popular: • AmphetaDesk (Perl) • NetNewsWire (OSX) • NewsCrawler (Win) • NewsMonster (Moz) • java.blogs is a ‘web based’ news aggregator for the Java community.

  12. Blogging using Java • Lots of blog software written in Java • 3 biggest projects: • Roller, SnipSnap and Blojsom • Other projects include: • PersonalBlog, MiniBlog, CocoBlog etc.

  13. Tools: Roller • www.rollerweblogger.org • The most advanced Java-based blogging tool • Supports comments, templating, RSS, XML-RPC, multi-user. • Deploys on Servlet container & JDBC database • Technologies used: • Persistence: Hibernate or Castor • MVC: Struts • Views: Velocity

  14. Tools: SnipSnap • www.snipsnap.org • Innovative Java-based ‘Bliki’ (Blog + Wiki) • Features include a complex Wiki rendering engine, comments, search, RSS, XML-RPC • Standalone Jetty instance with McKoi DB • Technologies: • Views: JSP • Everything else hand rolled!

  15. Tools: Blojsom • blojsom.sf.net • Java port of Bloxsom (Perl-based tool) • Uses the file system for persistence • Supports comments, RSS, XML-RPC, referrer tracking, searching. • Runs on JDK 1.4 w/ Servlet 2.3 container. • Technologies: • Flexible view dispatcher: JSP, Velocity or Freemarker

  16. Tools: Wrap Up • If you’re looking to start a new blog, without software - try freeroller http://www.freeroller.net • No installation required • Completely web based • Good way to get blogging!

  17. Agenda • Blogging & Java • What is java.blogs? • Technology behind javablogs.com

  18. java.blogs Overview • www.javablogs.com • A web aggregator for Java focused weblogs • Currently aggregates: • Over 1.5 million words • Written in 18,000+ entries • Posted by 360+ bloggers

  19. Information Flows Blogs (Internet) Thoughts RSS Feeds Bloggers java.blogs Browse Website Email Aggregated RSS Readers

  20. java.blogs Features • Single ‘feed’ of all Java blog entries • Decentralized, uncontrolled, focused community • Each blog owner controls their own blog • Tracks “popular” entries • Popular entries show what the community reads • Text & date searchable content • eg find all entries about “AOP” this week • Daily email notifications • Keep up to date with most popular entries from within your email client

  21. java.blogs daily update

  22. How is it different? • It is a true community of equals • Find a wide range of views on any topic • eg Over 30 entries discussing the impact of java.net within 24 hours of launch. • There is no ‘agenda’ - just personal views • “Good entries” rise to the top • More news than you can ever want • Now averaging over 200 entries / day

  23. 350 authors 1000 users Users in total control This is good and bad! Content is personal 100% opinions Analogy: having a conversation with 350 developers Few authors 290,000 users Centralised editorial Quality assurance Content is controlled Opinions in comments Analogy: reading a newspaper or magazine java.blogs vs TSS

  24. java.net? • java.net contains Sun ‘by-invitation only’ weblogs • This is good for Javablogs.com! • Many new blogs to aggregate (java.net has RSS): • James Gosling, • Sam Ruby, • Mike Clark, etc • See http://weblogs.java.net/ for more information.

  25. Agenda • Blogging & Java • What is java.blogs? • Technology behind javablogs.com

  26. javablogs.com Components Mail (JavaMail & Velocity) Scheduling(Quartz & Atlassian Scheduler) java.blogs code (Java!) Persistence (OFBiz) Non-Web DB (Postgres) XML / SOAP (Electric XML & Glue) Presentation (SiteMesh, WebWork & JSP) Search & Indexing (Lucene) User Management (OSUser) Web MVC (WebWork)

  27. Component Tour Scheduling Persistence Security MVC Indexing Mail Presentation

  28. Component Tour: Scheduling Scheduling Persistence Security MVC Indexing Mail Presentation Components: Quartz & atlassian-scheduler

  29. Scheduling: Quartz • www.part.net/quartz.html • J2EE job scheduling system • Alternatives? • Threads, util.Timer, external cron • Operates around a job/trigger model • Built in period and cron triggers • Extremely flexible, friendly component • USE: scheduling RSS retrieval, sending daily email updates, any periodic task • atlassian-scheduler is a Quartz XML config…

  30. Scheduling: Atlassian Scheduler • Example: scheduler-config.xml <scheduler> <jobs> <job name="Updater" class="com...UpdateJob" /> <job name="DailyEmail" class="com...EmailJob" /> </jobs> <triggers> <trigger name="UpdaterTrigger" job="Updater"> <period>3m</period> <startDelay>3m</startDelay> </trigger> <trigger name=”MailTrigger" job="DailyEmail" type="cron"> <startDelay>1m</startDelay> <expression>00***?</expression> </trigger> </triggers> </scheduler>

  31. Component Tour: Persistence Scheduling Persistence Security MVC Indexing Mail Presentation Component: OFBiz Entity Engine

  32. Persistence: OFBiz EE • www.ofbiz.org - Open For Business project • “Different” persistence engine • Light wrapper around JDBC datasources • Proud to be relational! • Data entities are generic value objects • Entity, field, view and relation definitions are in XML • Use: all data persistence in Javablogs.

  33. Persistence: OFBiz EE • Retrieving all blogs: Collection blogs = ee.findAll(“Blog”); • Retrieving a specific blog entity: Map idField = UtilMisc.toMap(“id”, id); GenericValue blog = ee.findByPrimaryKey("Blog", idField); • Getting and setting a field value: GenericValue blog = retrieveBlog(); String url = blog.getString(“url”); blog.set(“url”, newUrl); blog.store();

  34. Persistence: OFBiz EE • Retrieving blog entries: Collection entries = blog.getRelated(“ChildEntry”); • Complex find operation: Map fields = UtilMisc.toMap(“author”, “bob”); List sortorders = UtilMisc.toList(“dateadded”); entries = ee.findByAnd(“Blog”, fields, sortorders);

  35. Persistence: OFBiz EE • Automatically creates and updates tables • Code talks to the logical model • Logical model + field mappings = physical db OFBiz EE javablogs code Logical Model entitymodel.xml Physical Database Field Mappings fieldtypes-oracle.xml

  36. Persistence: OFBiz EE • Sample entity from entitymodel.xml <entity entity-name= "BlogEntry" package-name= "" > <field name= "id" type= "numeric" col-name= ”entry_id" /> <field name= "blog" type= "numeric" /> <field name= "title" type= "long-varchar" /> <field name= "created" type= "date-time" /> ... <prim-key field= "id" /> <relation type= "one" title= "Parent" rel-entity-name= "Blog" > <key-map field-name= "blog" rel-field-name= "id" /> </ relation > </ entity >

  37. Persistence: OFBiz EE • Sample of fieldtypes-postgres.xml <fieldtypemodel> <field-type-def type= "date-time" sql-type= "TIMESTAMP" java-type= "java.sql.Timestamp" /> <field-type-def type= "short-varchar" sql-type= "VARCHAR(60)" java-type= "String" /> <field-type-def type= "very-long" sql-type= "TEXT" java-type= "String" /> <field-type-def type= "credit-card-number" sql-type= "VARCHAR(40)" java-type= "String"> <validate name= "isAnyCard"/> </ field-type-def>

  38. Component Tour: Indexing Scheduling Persistence Security MVC Indexing Mail Presentation Component: Jakarta Lucene

  39. Indexing: Lucene • jakarta.apache.org/lucene • Thefull-text index and search component • Highly scalable and efficient architecture • Why use full text searching? • No more SQL: LIKE ‘%foo%’ • Used for full text search of blog entries

  40. Component Tour: Security Scheduling Persistence Security MVC Indexing Mail Presentation Components: OSUser & atlassian-security

  41. User Management: OSUser • www.opensymphony.com/osuser • Server-agnostic user management API • Handles user, group and profile data • Why needed? • User data different to other data • Pluggable storage providers (ie LDAP) • Writing portable J2EE auth code very hard

  42. User Management: OSUser • Providers for storage: • EJB, JDBC, OFBiz, Hibernate, LDAP, XML files etc • Adapters for server integration • Weblogic, Orion, JBoss, Resin etc javablogs code providers adapters • Storage • users • groups • profiles Application Server OSUser

  43. User Management: OSUser • Retrieving a specific user and their groups: User user = userManager.getUser(“fred”); Collection groups = user.getGroups(); • Retrieving a user’s profile: PropertySet profile = user.getPropertySet(); String country = profile.getString(“user.address.country”); Date signedUp = profile.getDate(“user.signup”); Long logins = profile.getLong(“user.numlogins”); • Creating a new user in the administrators group: User newUser = userManager.createUser(“mike”); newUser.setEmail(“mike@atlassian.com”); newUser.addToGroup(userManager.getGroup(“administrators”));

  44. Security: atlassian-security • Security is worst part of Servlet spec • Not portable between servers • Very limited URL patterns • To perform effective security checks on a web application, need to roll your own framework. • atlassian-security is our solution to this • in process of being open sourced

  45. atlassian-security architecture Concepts Integration Points

  46. atlassian-security Services • Services allow you to check the roles required for any request • Two bundled services: • Path Service: looks at the request URL. Allows extremely flexible path lookups • /admin/*, **/admin/*, /admin/Setup* etc • WebWork Service: looks at the action being executed • Other examples could be IPService or KeyService.

  47. atlassian-security PathService • PathService is configured in a security-paths.xml file: <security-paths> <path name= "admin"> <url-pattern>/secure/admin/*</url-pattern> <role-name>administrators</role-name> </path> <path name= "user"> <url-pattern>/secure/*</url-pattern> <role-name>users, developers</role-name> </path> </security-paths>

  48. atlassian-security Interceptors • Problem: run code before / after security events • Events? login, logout, auth attempts etc. • Under the Servlet spec you can’t do this. • Solution: AOP-like interceptors • Example: used in java.blogs to store the date of last login, and number of logins

  49. Component Tour: MVC Scheduling Persistence Security MVC Indexing Mail Presentation Component: OpenSymphony WebWork

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