1724 lines
46 KiB
HTML
1724 lines
46 KiB
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<li class="subfolders">
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<li><a href="pmd_rules_java_security.html">Security</a></li>
|
||
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|
||
|
||
</ul>
|
||
</li>
|
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|
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||
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||
|
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|
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|
||
|
||
|
||
|
||
<li class="subfolders">
|
||
<a href="#">Java Server Pages Rules</a>
|
||
<ul>
|
||
|
||
|
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|
||
<li><a href="pmd_rules_jsp.html">Index</a></li>
|
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|
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|
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|
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|
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<li><a href="pmd_rules_jsp_bestpractices.html">Best Practices</a></li>
|
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|
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<li><a href="pmd_rules_jsp_codestyle.html">Code Style</a></li>
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|
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<li><a href="pmd_rules_jsp_errorprone.html">Error Prone</a></li>
|
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|
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||
|
||
|
||
|
||
<li><a href="pmd_rules_jsp_security.html">Security</a></li>
|
||
|
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|
||
|
||
</ul>
|
||
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|
||
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||
|
||
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|
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|
||
|
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|
||
<li class="subfolders">
|
||
<a href="#">Maven POM Rules</a>
|
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<ul>
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|
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|
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<li><a href="pmd_rules_pom.html">Index</a></li>
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<li><a href="pmd_rules_pom_errorprone.html">Error Prone</a></li>
|
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</ul>
|
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|
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|
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|
||
<li class="subfolders">
|
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<a href="#">Modelica Rules</a>
|
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<ul>
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<li><a href="pmd_rules_modelica_bestpractices.html">Best Practices</a></li>
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|
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<li class="subfolders">
|
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<a href="#">PLSQL Rules</a>
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<ul>
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<li><a href="pmd_rules_plsql_bestpractices.html">Best Practices</a></li>
|
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|
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<li><a href="pmd_rules_plsql_codestyle.html">Code Style</a></li>
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|
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|
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|
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|
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<li class="subfolders">
|
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<a href="#">Salesforce VisualForce Rules</a>
|
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<ul>
|
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|
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|
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<li><a href="pmd_rules_vf.html">Index</a></li>
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<li><a href="pmd_rules_vf_security.html">Security</a></li>
|
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|
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</ul>
|
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|
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||
|
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|
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|
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<li class="subfolders">
|
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<a href="#">Scala Rules</a>
|
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<ul>
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|
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<li><a href="pmd_rules_scala.html">Index</a></li>
|
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|
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|
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</ul>
|
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|
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|
||
|
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|
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<li class="subfolders">
|
||
<a href="#">VM Rules</a>
|
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<ul>
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<li><a href="pmd_rules_vm.html">Index</a></li>
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<li><a href="pmd_rules_vm_bestpractices.html">Best Practices</a></li>
|
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|
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<li><a href="pmd_rules_vm_design.html">Design</a></li>
|
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<li><a href="pmd_rules_vm_errorprone.html">Error Prone</a></li>
|
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|
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|
||
|
||
</ul>
|
||
</li>
|
||
|
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|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li class="subfolders">
|
||
<a href="#">WSDL Rules</a>
|
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<ul>
|
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|
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|
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|
||
<li><a href="pmd_rules_wsdl.html">Index</a></li>
|
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|
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|
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|
||
</ul>
|
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</li>
|
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|
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|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li class="subfolders">
|
||
<a href="#">XML Rules</a>
|
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<ul>
|
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|
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|
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|
||
<li><a href="pmd_rules_xml.html">Index</a></li>
|
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|
||
|
||
|
||
|
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|
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<li><a href="pmd_rules_xml_errorprone.html">Error Prone</a></li>
|
||
|
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|
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|
||
</ul>
|
||
</li>
|
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||
|
||
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||
|
||
|
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|
||
|
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|
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|
||
|
||
|
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|
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<li class="subfolders">
|
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<a href="#">XSL Rules</a>
|
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<ul>
|
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|
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|
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|
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<li><a href="pmd_rules_xsl.html">Index</a></li>
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|
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<li><a href="pmd_rules_xsl_codestyle.html">Code Style</a></li>
|
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|
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<li><a href="pmd_rules_xsl_performance.html">Performance</a></li>
|
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|
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|
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|
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</ul>
|
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</li>
|
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|
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|
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|
||
|
||
|
||
|
||
|
||
</ul>
|
||
</li>
|
||
|
||
|
||
|
||
<li>
|
||
|
||
<a href="#">Language Specific Documentation</a>
|
||
|
||
<ul>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_languages_jsp.html">JSP Support</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li class="subfolders">
|
||
<a href="#">Java Support</a>
|
||
<ul>
|
||
|
||
|
||
|
||
<li><a href="pmd_languages_java.html">Java Versions</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_java_metrics_index.html">Java Code Metrics</a></li>
|
||
|
||
|
||
|
||
</ul>
|
||
</li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_apex_metrics_index.html">Apex code metrics</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_languages_plsql.html">PLSQL</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_languages_visualforce.html">Visualforce</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_languages_xml.html">XML and XML dialects</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_languages_html.html">HTML</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_languages_gherkin.html">Gherkin</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
</ul>
|
||
</li>
|
||
|
||
|
||
|
||
<li>
|
||
|
||
<a href="#">Developer Documentation</a>
|
||
|
||
<ul>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_development.html">Developer resources</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_building.html">Building PMD from source</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="https://github.com/pmd/pmd/blob/master/CONTRIBUTING.md" target="_blank">Contributing</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_writing_documentation.html">Writing documentation</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_roadmap.html">Roadmap</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_how_pmd_works.html">How PMD works</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_pmdtester.html">Pmdtester</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_rule_deprecation_policy.html">Rule Deprecation Policy</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li class="subfolders">
|
||
<a href="#">Major contributions</a>
|
||
<ul>
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_major_rule_guidelines.html">Rule Guidelines</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_major_adding_new_language.html">Adding a new language</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_major_adding_new_cpd_language.html">Adding a new CPD language</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_major_adding_new_metrics_framework.html">Adding metrics support to a language</a></li>
|
||
|
||
|
||
|
||
</ul>
|
||
</li>
|
||
|
||
|
||
|
||
<li class="subfolders">
|
||
<a href="#">Experimental features</a>
|
||
<ul>
|
||
|
||
|
||
|
||
<li><a href="pmd_devdocs_experimental_ast_dump.html">Creating (XML) dump of the AST</a></li>
|
||
|
||
|
||
|
||
</ul>
|
||
</li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
</ul>
|
||
</li>
|
||
|
||
|
||
|
||
<li>
|
||
|
||
<a href="#">Project documentation</a>
|
||
|
||
<ul>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li class="subfolders">
|
||
<a href="#">Trivia about PMD</a>
|
||
<ul>
|
||
|
||
|
||
|
||
<li><a href="pmd_projectdocs_trivia_news.html">PMD in the press</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_projectdocs_trivia_products.html">Products & books related to PMD</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_projectdocs_trivia_similarprojects.html">Similar projects</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_projectdocs_trivia_meaning.html">What does 'PMD' mean?</a></li>
|
||
|
||
|
||
|
||
</ul>
|
||
</li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_projectdocs_faq.html">FAQ</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="license.html">License</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_projectdocs_credits.html">Credits</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_release_notes_old.html">Old release notes</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li class="active"><a href="pmd_projectdocs_decisions.html">Decisions</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
<li class="subfolders">
|
||
<a href="#">Project management</a>
|
||
<ul>
|
||
|
||
|
||
|
||
<li><a href="pmd_projectdocs_committers_infrastructure.html">Infrastructure</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_projectdocs_committers_releasing.html">Release process</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_projectdocs_committers_merging_pull_requests.html">Merging pull requests</a></li>
|
||
|
||
|
||
|
||
|
||
|
||
<li><a href="pmd_projectdocs_committers_main_landing_page.html">Main Landing page</a></li>
|
||
|
||
|
||
|
||
</ul>
|
||
</li>
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
</ul>
|
||
</li>
|
||
|
||
|
||
|
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<!-- if you aren't using the accordion, uncomment this block:
|
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<p class="external">
|
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<a href="#" id="collapseAll">Collapse All</a> | <a href="#" id="expandAll">Expand All</a>
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</p>
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-->
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</ul>
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|
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<script>$("li.active").parents('li').toggleClass("active");</script>
|
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|
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</div>
|
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|
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|
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|
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<!-- Content Column -->
|
||
<div class="col-md-9" id="tg-sb-content">
|
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<header>
|
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<div class="row">
|
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<div class="col-lg-12">
|
||
<a href="./" role="button"
|
||
><i class="fa fa-home fa-lg"></i
|
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></a>
|
||
» ADR 2 - Policy on the use of Kotlin for development
|
||
<a
|
||
target="_blank"
|
||
href="https://github.com/pmd/pmd/blob/master/docs/pages/pmd/projectdocs/decisions/adr-2.md"
|
||
class="pull-right"
|
||
role="button"
|
||
><i class="fa fa-github fa-lg"></i> Edit on GitHub</a
|
||
>
|
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|
||
</div>
|
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</div>
|
||
|
||
<hr />
|
||
</header>
|
||
|
||
|
||
<div class="post-header">
|
||
<h1 class="post-title-main">ADR 2 - Policy on the use of Kotlin for development</h1>
|
||
</div>
|
||
|
||
|
||
|
||
<div class="post-content" data-github-edit-url="https://github.com/pmd/pmd/blob/master/docs/pages/pmd/projectdocs/decisions/adr-2.md">
|
||
|
||
|
||
<div id="inline-toc"><!-- empty, move TOC here when screen size too small --></div>
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||
<h1 id="context">Context</h1>
|
||
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||
<p>We currently use Kotlin only for unit tests at some places (e.g. pmd-lang-test module provides a couple of base
|
||
test classes). We were cautious to expand Kotlin because of poor development support outside JetBrain’s
|
||
IntelliJ IDEA. E.g. the <a href="https://marketplace.eclipse.org/content/kotlin-plugin-eclipse">Kotlin Plugin for Eclipse</a>
|
||
doesn’t work properly as described in the reviews.</p>
|
||
|
||
<p>For VS Code there is a <a href="https://marketplace.visualstudio.com/items?itemName=mathiasfrohlich.Kotlin">Kotlin Plugin</a>
|
||
with basic features. Online IDEs like gitpod.io and GitHub Codespaces are often based on VS Code.</p>
|
||
|
||
<p>Using Kotlin means, that we accept, that PMD can only be developed with IntelliJ IDEA. This feels like a vendor lock-in.</p>
|
||
|
||
<p>Also, bringing in a mix of languages might make maintenance a bit harder and make it harder for new contributors.
|
||
However - PMD is a tool that deals with many, many languages anyway, so this is maybe not a real argument.</p>
|
||
|
||
<p>Nevertheless, extending the usage of Kotlin within PMD can also increase contributions.</p>
|
||
|
||
<h1 id="decision">Decision</h1>
|
||
|
||
<p>We are generally open to the idea to increase usage of Kotlin within PMD. In order to gain experience
|
||
and to keep it within bounds and therefore maintainable we came up with the following rules:</p>
|
||
|
||
<ul>
|
||
<li>The module <code class="language-plaintext highlighter-rouge">pmd-core</code> should stay in plain Java. This helps in keeping binary compatibility when changing sources.
|
||
<code class="language-plaintext highlighter-rouge">pmd-core</code> contains the main APIs for all language modules. We currently release all modules at the same time,
|
||
so this is not a real problem for now. But that might change in the future: Because only few language modules have
|
||
actual changes per release, it doesn’t really make sense to release everything as long as the modules stay
|
||
compatible. But that’s another story.</li>
|
||
<li>For (unit) testing, Kotlin can be used in <code class="language-plaintext highlighter-rouge">pmd-core</code> and in the language modules. The test frameworks can also
|
||
use Kotlin (<code class="language-plaintext highlighter-rouge">pmd-test</code> doesn’t yet, <code class="language-plaintext highlighter-rouge">pmd-lang-test</code> does already).</li>
|
||
<li>Additionally: from now on, we allow to have the individual language modules be implemented in different languages
|
||
when it makes sense. So, a language module might decide to use plain Java (like now) or also Kotlin.</li>
|
||
<li>When mixing languages (e.g. Java + Kotlin), we need to care that the modules can still be used with plain Java.
|
||
E.g. when writing custom rules: <code class="language-plaintext highlighter-rouge">pmd-java</code> provides a couple of APIs for rules (like symbol table, type resolution)
|
||
and we should not force the users to use Kotlin (at least not for language modules which already exist and
|
||
for which users might have written custom rules in Java already).</li>
|
||
<li>It is also possible to write the entire language module in Kotlin only. Then the rules would be written in Kotlin
|
||
as well. And the possible problems when mixing languages are gone. But that applies only for new language modules.</li>
|
||
<li>When refactoring an existing language module from Java only to introduce Kotlin, care needs to be taken to
|
||
not make incompatible changes. If compatibility (binary or source) can’t be maintained, then that would be a
|
||
major version change.</li>
|
||
</ul>
|
||
|
||
<h1 id="status">Status</h1>
|
||
|
||
<p>Accepted (Last updated: September 2022)</p>
|
||
|
||
<h1 id="consequences">Consequences</h1>
|
||
|
||
<p>Allowing more Kotlin in PMD can attract new contributions. It might make it easier to develop small DSLs.
|
||
In the future we might also consider to use other languages than Kotlin, e.g. for <code class="language-plaintext highlighter-rouge">pmd-scala</code> Scala might make sense.</p>
|
||
|
||
<p>On the other side, other IDEs than IntelliJ IDEA will have a difficult time to deal with PMD’s source code
|
||
when Kotlin is used. Eclipse can’t be used practically anymore.</p>
|
||
|
||
<p>Maintaining a polyglot code base with multiple languages is likely to be more challenging.</p>
|
||
|
||
<h1 id="change-history">Change History</h1>
|
||
|
||
<p>2022-09-30: Changed status to “Accepted”.</p>
|
||
|
||
<p>2022-07-28: Proposed initial version.</p>
|
||
|
||
|
||
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