Merge pull request #4170 from adangel:issue-4140-doc-max-lang-version

[doc] Rule doc: add maximum language version #4170

docs/pages/release_notes.md

@@ -38,6 +38,8 @@ The rule is part of the quickstart.xml ruleset.
 * doc
     * [#4144](https://github.com/pmd/pmd/pull/4144): \[doc] Update docs to reflect supported languages
     * [#4163](https://github.com/pmd/pmd/issues/4163): \[doc] Broken links on page "Architecture Decisions"
+* java-bestpractices
+    * [#4140](https://github.com/pmd/pmd/issues/4140): \[java] \[doc] AccessorClassGeneration violations hidden with Java 11
 * java-codestyle
     * [#4139](https://github.com/pmd/pmd/issues/4139): \[java] UnnecessaryFullyQualifiedName FP when the same simple class name exists in the current package
 * java-documentation

pmd-doc/src/main/java/net/sourceforge/pmd/docs/RuleDocGenerator.java

@@ -392,6 +392,12 @@ private void generateRuleSetIndex(Map<Language, List<RuleSet>> rulesets) throws
                         lines.add("");
                     }
 
+                    if (rule.getMaximumLanguageVersion() != null) {
+                        lines.add("**Maximum Language Version:** "
+                                + rule.getLanguage().getName() + " " + rule.getMaximumLanguageVersion().getVersion());
+                        lines.add("");
+                    }
+
                     lines.addAll(EscapeUtils.escapeLines(toLines(stripIndentation(rule.getDescription()))));
                     lines.add("");
 

pmd-doc/src/test/resources/expected/sample.md

@@ -155,6 +155,8 @@ Avoid jumbled loop incrementers - its usually a mistake, and is confusing even i
 
 **Minimum Language Version:** Java 1.5
 
+**Maximum Language Version:** Java 11
+
 Override both `public boolean Object.equals(Object other)`, and `public int Object.hashCode()`, or override neither.
 Even if you are inheriting a `hashCode()` from a parent class, consider implementing hashCode and explicitly
 delegating to your superclass.

pmd-doc/src/test/resources/rulesets/ruledoctest/sample.xml

@@ -89,7 +89,8 @@ public class Bar {
           message="Ensure you override both equals() and hashCode()"
           class="net.sourceforge.pmd.lang.java.rule.errorprone.OverrideBothEqualsAndHashcodeRule"
           externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_sample.html#overridebothequalsandhashcode"
-          minimumLanguageVersion="1.5">
+          minimumLanguageVersion="1.5"
+          maximumLanguageVersion="11">
       <description>
             Override both `public boolean Object.equals(Object other)`, and `public int Object.hashCode()`, or override neither.
             Even if you are inheriting a `hashCode()` from a parent class, consider implementing hashCode and explicitly

pmd-java/src/main/resources/category/java/bestpractices.xml

@@ -42,11 +42,15 @@ public abstract class Foo {
           class="net.sourceforge.pmd.lang.java.rule.bestpractices.AccessorClassGenerationRule"
           externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#accessorclassgeneration">
         <description>
-Instantiation by way of private constructors from outside of the constructor's class often causes the
+Instantiation by way of private constructors from outside the constructor's class often causes the
 generation of an accessor. A factory method, or non-privatization of the constructor can eliminate this
 situation. The generated class file is actually an interface.  It gives the accessing class the ability
 to invoke a new hidden package scope constructor that takes the interface as a supplementary parameter.
 This turns a private constructor effectively into one with package scope, and is challenging to discern.
+
+_Note:_ This rule is only executed for Java 10 or lower.
+Since Java 11, [JEP 181: Nest-Based Access Control](https://openjdk.org/jeps/181) has been implemented. This
+means that in Java 11 and above accessor classes are not generated anymore.
         </description>
         <priority>3</priority>
         <example>
@@ -74,6 +78,11 @@ public class Outer {
 When accessing private fields / methods from another class, the Java compiler will generate accessor methods
 with package-private visibility. This adds overhead, and to the dex method count on Android. This situation can
 be avoided by changing the visibility of the field / method from private to package-private.
+
+
+_Note:_ This rule is only executed for Java 10 or lower.
+Since Java 11, [JEP 181: Nest-Based Access Control](https://openjdk.org/jeps/181) has been implemented. This
+means that in Java 11 and above accessor classes are not generated anymore.
         </description>
         <priority>3</priority>
         <example>