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Efficient Code Organisation
- 1. By: Lennart Jörelid JavaOne 2012 -‐ BOF6357
- 2. By: Lennart Jörelid ¡ Lennart Jörelid, jGuru Europe AB § Builds large-‐scale JEE systems § Enterprise and OSS dev/arch since 1995
- 3. By: Lennart Jörelid 1: Problem The costly on-‐boarding process 2: Usability Projects & usability engineering 3: Tooling Structuring & enforcing projects 4: Q & A Q & A
- 4. By: Lennart Jörelid ¡ Java programming in itself § Assumtion: You know Java, Projects … & Maven ¡ In-‐depth Human Computer Interaction / Usability Engineering and Design § Instead, this talk serves to inspire you § Apply usability engineering to areas where it is seldom considered § Developers are also users … of VCSs/projects/tooling
- 5. By: Lennart Jörelid 1: Problem Terms, concepts, patterns
- 6. By: Lennart Jörelid We aim for end-‐user quality and usability in our software. Do we also provide usability for ourselves? Do you have useable and well-‐designed codebases?
- 7. By: Lennart Jörelid Frequency … moved between projects a lot? Relevance … felt introduction was great? Experience … was helped by tooling to reduce the need for reading/mentoring? Characteristics … works/ed in big projects?
- 8. By: Lennart Jörelid Application … designed APIs using principles of HCI? Consequence … applied usability to design VCS structure? Tooling … set up Maven plugins to give feedback to developers when guidelines are broken? Usability … knows or studied usability engineering?
- 9. By: Lennart Jörelid ¡ Introduction of new coworkers is too costly § Takes too long; inefbicient domain explanation ¡ Difbicult to bind/understand/apply standards § Where are the active standards debinitions? § ”Wade through the Wiki/Sharepoint syndrome” § Limited feedback before committing code § Limited tooling enforcing your development & design ¡ VCS structured for builds, not assist understanding § Domain ó VCS ó Build system disconnect § ”Where is the domain model for FooBar”?
- 10. By: Lennart Jörelid Organisation Presentation [Project] Manager Product Presentation [Biz] Architect [Scrum] Team Presentation Scrum Master Learning curve [Yourself] Wiki, Templace, … Productivity [Yourself] OSS
- 11. By: Lennart Jörelid Scrum Master Learning curve Organisation Presentation [Project] Manager Product Presentation [Biz] Architect [Scrum] Team Presentation [Yourself] Wiki, Templace, … Productivity [Yourself] Documents
- 12. By: Lennart Jörelid Time-‐consuming/costly to produce When written: did you document all of it? Difbicult to bind when needed When found: is it updated/current? Time-‐consuming/costly to consume When read: do you understand it all?
- 13. By: Lennart Jörelid ¡ Reduce the need to read documents § Reduced reading time ó increased pace § Re-‐use component patterns ¡ Reduce the number of concepts in a VCS § Aim for manageable ”mouthfuls” manageable by the short-‐term memory § Enforce consistency in naming, structure etc. § … to comply with your development guidelines…
- 14. By: Lennart Jörelid Usability, Project structure and Learning 2: Usability
- 15. By: Lennart Jörelid ¡ Apply usability to project design § Originate from the human mind & learning § Adhere to standard design principles [HCI] ¡ This requires some [basic] knowledge of § … the learning process § … available design principles § … usability engineering
- 16. By: Lennart Jörelid Sensory Input Short-‐term Memory Long-‐term Memory ”7 ± 2” ~ seconds ”Unlimited” Indefinite ~ instant
- 17. By: Lennart Jörelid Visibility Affordance What does X do? How do I use X? Feedback I see the state of X. Constraint I can’t use X in a certain way. Consistency I use X2 like I used X1.
- 18. By: Lennart Jörelid ¡ Efbicient projects à Trees of Components § Move towards 7±2 folders visible § Design principles applied ”Component” is really overloaded. How do we define it here?
- 19. By: Lennart Jörelid Pattern A way to sustainably reduce dependency tanglement Shared patterns in the codebase VCS structure & Naming pattern Coding & semantic standard Dependency Ctrl A way to sustainably reduce dependency tanglement Requirement in enforcing coding standards Depdendency pattern & -‐classification Enforcement rules Simplibication A way to promote better architectural overview A means to reduce scope and complexity Common classification of projects Compliance with design principles
- 20. By: Lennart Jörelid Accessed via an API and Model • 2 public [Maven] projects • C.f. OSGi, Jigsaw, JBoss modules, … API dependency imported by client • Implementation projects injected • Implementation types unavailable during development • è Loose coupling (Good!)
- 21. By: Lennart Jörelid Dependencies in Sw Component foo Structure in VCS foo-‐model foo-‐api foo-‐impl-‐bar foo-‐impl-‐gnat foo-‐spi-‐gnu No model. ó ”Library” Model. ó ”Domain Component” foo-‐example Copy & paste code
- 22. By: Lennart Jörelid x-‐model Component en))es (annotated POJOs) holding component (business) state No dependencies to other component projects x-‐api Component service specifica)on (i.e. Interfaces, Excep)ons and Abstract classes). Depends only on the Model Project x-‐impl-‐y Component service implementa)on Depends on the API, and any required external dependencies x-‐example Project holding runnable, well-‐documented code code illustra)ng the use of the API. (copy/paste)
- 23. By: Lennart Jörelid ¡ ”Relatively few” (7±2) components to grasp § Simplibies learning and augments overview § Important to support this in IDEs… poor Eclipse-‐users
- 24. By: Lennart Jörelid Components Component Projects 3 impl projects!
- 25. By: Lennart Jörelid ¡ Use SoftwareComponent concept § Visibility, Consistency, Affordance ¡ Learning Process § Grouping and Design of VCS / software repo ¡ Tooling § Constaints, Feedback
- 26. By: Lennart Jörelid Designing efbicient projects Enforcing standards & design 3: Tooling
- 27. By: Lennart Jörelid ¡ Tooling reduce the need for documentation § ”Enforce if possible, Document if required” ¡ Conbigure tooling in a shared Codestyle project § Global dependency; used in build cycle debinition § Same code validation on workstations and CI server ¡ Several Maven plugins exist § Enforcer plugin, Checkstyle plugin, Cobertura plugin, Findbugs plugin, CPD plugin, …
- 28. By: Lennart Jörelid ¡ Maven Enforcer Plugin [Build criteria] § Uses stock and custom rules (Java classes) § Custom rules frequently needed ¡ Maven Checkstyle Plugin [Code style] § Uses checkstyle.xml rule conbiguration § Seldom need to write custom checkstyle rules ¡ Maven Cobertura Plugin [Test coverage] § Uses unit tests and conbiguration § No need to write custom plugin rules
- 29. By: Lennart Jörelid Enforcer Conbiguration & custom rules Code Quality Checkstyle/PMD/Findbugs conbig. Cobertura Unit test Coverage reports
- 30. By: Lennart Jörelid <plugin> <artifactId>maven-‐enforcer-‐plugin</artifactId> <version>1.3.1</version> <executions> <execution> <id>enforce-‐imports</id> <goals> <goal>enforce</goal> </goals> <configuration> <rules> <requireMavenVersion> <version>[3.0.5,)</version> </requireMavenVersion> <requireJavaVersion> <version>${jdk.version}</version> </requireJavaVersion> <validateProjectTypes implementation=“se.jguru.nazgul.tools.codestyle. enforcer.rules.ValidateProjectType”/> </rules> </configuration> </execution> </executions> … Plugin goal definition Stock rules Custom rules
- 31. By: Lennart Jörelid … <dependencies> <dependency> <groupId>se.jguru.nazgul.tools.codestyle</groupId> <artifactId>nazgul-‐codestyle</artifactId> <version>2.0.9</version> </dependency> </dependencies> </plugin> Custom rules Dependency project
- 32. By: Lennart Jörelid Rule Meaning bannedDependencies Enforces that excluded dependencies aren't included. bannedPlugins Enforces that excluded plugins aren't included. dependencyConvergence Ensure all dependencies converge to the same version. evaluateBeanshell Evaluates a beanshell script. requireReleaseDeps Enforces that no snapshots are included as dependencies. requireReleaseVersion Enforces that the artifact is not a snapshot. requireMavenVersion Enforces the Maven version.
- 33. By: Lennart Jörelid Create Project Create a tool project holding your rules Imports Import enforcer-‐api & maven deps Implement 1 class per rule type Usage Use the enforcement rules in your poms
- 34. By: Lennart Jörelid <dependency> <groupId>org.apache.maven.enforcer</groupId> <artifactId>enforcer-‐api</artifactId> <version>${api.version}</version> </dependency> <dependency> <groupId>org.apache.maven</groupId> <artifactId>maven-‐project</artifactId> <version>${maven.version}</version> </dependency> <dependency> <groupId>org.apache.maven</groupId> <artifactId>maven-‐artifact</artifactId> <version>${maven.version}</version> </dependency> <dependency> <groupId>org.apache.maven</groupId> <artifactId>maven-‐plugin-‐api</artifactId> <version>${maven.version}</version> </dependency> Enforcer API Maven integration
- 35. By: Lennart Jörelid Execution entry point /** * This is the interface into the rule. This method should throw an exception * containing a reason message if the rule fails the check. The plugin will * then decide based on the fail flag if it should stop or just log the * message as a warning. * * @param helper The helper provides access to the log, MavenSession and has * helpers to get common components. It is also able to lookup components * by class name. * * @throws EnforcerRuleException the enforcer rule exception */ void execute( EnforcerRuleHelper helper ) throws EnforcerRuleException;
- 36. By: Lennart Jörelid public final void execute(EnforcerRuleHelper helper) throws EnforcerRuleException { // Acquire some Maven object from Maven expressions MavenProject project = (MavenProject) helper.evaluate("${project}"); MavenSession session = (MavenSession) helper.evaluate("${session}”); String target = (String) helper.evaluate("${project.build.directory}”); String artifactId = (String) helper.evaluate("${project.artifactId}”); … POM Maven3 variables
- 37. By: Lennart Jörelid /** * Delegate method, implemented by concrete subclasses. … * @throws RuleFailureException If the enforcer rule was not satisfied. */ @Override protected void performValidation( final MavenProject project, final EnforcerRuleHelper helper) throws RuleFailureException { try { ProjectType.getProjectType(project); } catch (IllegalArgumentException e) { throw new RuleFailureException(e.getMessage()); } } Yay! The criterion!
- 38. By: Lennart Jörelid Enum with all known project types Pattern matching to define type Factory method
- 39. By: Lennart Jörelid Plugin Conbiguration & rules debinitions Checkstyle.xml Checkstyle conbiguration document Learning more Checkstyle site
- 40. By: Lennart Jörelid <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-‐checkstyle-‐plugin</artifactId> <version>${checkstyle.plugin.version}</version> <dependencies> <dependency> <groupId>se.jguru.foundation.tools</groupId> <artifactId>codestyle</artifactId> <version>${tools.codestyle.version}</version> </dependency> </dependencies> <configuration> <configLocation>codestyle/checkstyle.xml</configLocation> <failOnViolation>true</failOnViolation> <violationSeverity>error</violationSeverity> </configuration> </plugin> Codestyle project Checkstyle configuration
- 41. By: Lennart Jörelid Checkstyle configuration
- 42. By: Lennart Jörelid <?xml version="1.0" encoding="UTF-‐8"?> <!DOCTYPE module PUBLIC "-‐//Puppy Crawl//DTD Check Configuration 1.3//EN” "http://www.puppycrawl.com/dtds/configuration_1_3.dtd"> <module name="Checker"> <property name="severity" value="warning"/> <module name="TreeWalker"> -‐-‐-‐ rules -‐-‐-‐ <!-‐-‐ We should not use Calendar or Date types in any public method. They could be used internally -‐ and only within model classes to cope with JPA time types – but not within parameters or return types. -‐-‐> <module name="IllegalType"> <property name="severity" value="error"/> <property name="tokens" value="PARAMETER_DEF, METHOD_DEF"/> <property name="illegalClassNames” value="java.util.GregorianCalendar, java.util.Calendar, java.util.Date, java.util.Vector"/> </module> Breaks the build!
- 43. By: Lennart Jörelid Plugin Conbiguration & coverage debinitions Reports Understanding cobertura reports
- 44. By: Lennart Jörelid <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>cobertura-‐maven-‐plugin</artifactId> <version>${cobertura.plugin.version}</version> <configuration> <instrumentation> <includes> <include>se/jguru/foo/**/*.class</include> </includes> <excludes> <exclude>se/jguru/**/*Exception.class</exclude> <exclude>se/jguru/generated/**/*.class</exclude> </excludes> </instrumentation> <check> <branchRate>65</branchRate> <lineRate>80</lineRate> <haltOnFailure>true</haltOnFailure> </check> </configuration> </plugin> Control excludes Rates
- 45. By: Lennart Jörelid ”Line Coverage” % lines in release code executed by unit tests ”Branch Coverage” % branches in release code executed by unit tests … ”branch” == possible execution path …
- 46. By: Lennart Jörelid ¡ Generated in the build process § mvn site ¡ Find reports in target/site § Simply open with a web browser
- 48. By: Lennart Jörelid 16 times covered 93 % coverage Unit test coverage miss Unnecessary code? Insufficient tests?
- 49. By: Lennart Jörelid What is ”Conditional coverage”?
- 50. By: Lennart Jörelid ¡ Enforces the development handbook § Ensures that no project shortcuts can be taken ¡ Enforced using maven-‐enforcer plugin § … and checkstyle as well § Uses your custom rules to feed the enforcer
- 51. By: Lennart Jörelid ¡ Efbicient projects need appropriate design § Reducing the need for excessive documentation improves ratio of productive to waste time ¡ Automatic validation of projects, code and dependencies improve usability § Use appropriate plugins to implement enforcement ¡ FOSS sample provided …
- 52. By: Lennart Jörelid PoC provided – clone, use and give me feedback http://bitbucket.org/lennartj/nazgul_tools http://bitbucket.org/lennartj/nazgul_core
- 53. By: Lennart Jörelid Any questions? 4: Q & A
- 54. By: Lennart Jörelid Thank you for attending