# Documentation

Rules that are related to code documentation.
Table of Contents

## CommentContent

Since: PMD 5.0

Priority: Medium (3)

A rule for the politically correct… we don’t want to offend anyone.

This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.documentation.CommentContentRule

Example(s):

    //OMG, this is horrible, Bob is an idiot !!!

This rule has the following properties:

Name | Default Value | Description
--- | --- | ---
forbiddenRegex | idiot|jerk | Illegal terms or phrases

Use this rule with the default properties by just referencing it:

    <rule ref="category/java/documentation.xml/CommentContent" />

Use this rule and customize it:

    <rule ref="category/java/documentation.xml/CommentContent">
        <properties>
            <property name="forbiddenRegex" value="idiot|jerk" />
        </properties>
    </rule>

## CommentRequired

Since: PMD 5.1

Priority: Medium (3)

Denotes whether javadoc (formal) comments are required (or unwanted) for specific language elements.

This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.documentation.CommentRequiredRule

Example(s):

    /**
    *
    *
    * @author Jon Doe
    */

This rule has the following properties:

Name | Default Value | Description
--- | --- | ---
methodWithOverrideCommentRequirement | ignored | Comments on @Override methods One of: `ignored`, `required`, `unwanted`
accessorCommentRequirement | ignored | Comments on getters and setters" One of: `ignored`, `required`, `unwanted`
classCommentRequirement | required | Class comments One of: `ignored`, `required`, `unwanted`
fieldCommentRequirement | required | Field comments One of: `ignored`, `required`, `unwanted`
publicMethodCommentRequirement | required | Public method and constructor comments One of: `ignored`, `required`, `unwanted`
protectedMethodCommentRequirement | required | Protected method constructor comments One of: `ignored`, `required`, `unwanted`
enumCommentRequirement | required | Enum comments One of: `ignored`, `required`, `unwanted`
serialVersionUIDCommentRequired | ignored | Serial version UID comments One of: `ignored`, `required`, `unwanted`
serialPersistentFieldsCommentRequired | ignored | Serial persistent fields comments One of: `ignored`, `required`, `unwanted`

Use this rule with the default properties by just referencing it:

    <rule ref="category/java/documentation.xml/CommentRequired" />

Use this rule and customize it:

    <rule ref="category/java/documentation.xml/CommentRequired">
        <properties>
            <property name="methodWithOverrideCommentRequirement" value="ignored" />
            <property name="accessorCommentRequirement" value="ignored" />
            <property name="classCommentRequirement" value="required" />
            <property name="fieldCommentRequirement" value="required" />
            <property name="publicMethodCommentRequirement" value="required" />
            <property name="protectedMethodCommentRequirement" value="required" />
            <property name="enumCommentRequirement" value="required" />
            <property name="serialVersionUIDCommentRequired" value="ignored" />
            <property name="serialPersistentFieldsCommentRequired" value="ignored" />
        </properties>
    </rule>

## CommentSize

Since: PMD 5.0

Priority: Medium (3)

Determines whether the dimensions of non-header comments found are within the specified limits.

This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.documentation.CommentSizeRule

Example(s):

    /**
    *
    *   too many lines!
    *
    *
    *
    *
    *
    *
    *
    *
    *
    *
    *
    *
    */

This rule has the following properties:

Name | Default Value | Description
--- | --- | ---
maxLines | 6 | Maximum lines
maxLineLength | 80 | Maximum line length

Use this rule with the default properties by just referencing it:

    <rule ref="category/java/documentation.xml/CommentSize" />

Use this rule and customize it:

    <rule ref="category/java/documentation.xml/CommentSize">
        <properties>
            <property name="maxLines" value="6" />
            <property name="maxLineLength" value="80" />
        </properties>
    </rule>

## DanglingJavadoc

Since: PMD 7.17.0

Priority: Medium (3)

Javadoc comments that do not belong to a class, method or field are ignored by the JavaDoc tool and don’t end up in the generated API documentation. Such comments are either misplaced (e.g. between annotations and method declaration) or should be block comments.

In order to fix this violation, the comment should be moved to the correct place, converted into a block comment or removed completely.

This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.documentation.DanglingJavadocRule

Example(s):

    public class Foo {
      /**
       * Public methods // wrong
       */

      /**
       * A setter // OK
       */
       public void setFoo() {

       }

    }

Use this rule by referencing it:

    <rule ref="category/java/documentation.xml/DanglingJavadoc" />

## UncommentedEmptyConstructor

Since: PMD 3.4

Priority: Medium (3)

Uncommented Empty Constructor finds instances where a constructor does not contain statements, but there is no comment. By explicitly commenting empty constructors it is easier to distinguish between intentional (commented) and unintentional empty constructors.

This rule is defined by the following XPath expression:

    //ConstructorDeclaration[@Visibility != "private"]
                            [not(
                                   pmd-java:hasAnnotation('javax.inject.Inject')
                                or pmd-java:hasAnnotation('org.springframework.beans.factory.annotation.Autowired')
                            )]
                            [Block[
                                @containsComment = false()
                                and (count(*) = 0 or ($ignoreExplicitConstructorInvocation = true() and count(*) = 1 and ExplicitConstructorInvocation))
                            ]]

Example(s):

    public Foo() {
      // This constructor is intentionally empty. Nothing special is needed here.
    }

This rule has the following properties:

Name | Default Value | Description
--- | --- | ---
ignoreExplicitConstructorInvocation | false | Ignore explicit constructor invocation when deciding whether constructor is empty or not

Use this rule with the default properties by just referencing it:

    <rule ref="category/java/documentation.xml/UncommentedEmptyConstructor" />

Use this rule and customize it:

    <rule ref="category/java/documentation.xml/UncommentedEmptyConstructor">
        <properties>
            <property name="ignoreExplicitConstructorInvocation" value="false" />
        </properties>
    </rule>

## UncommentedEmptyMethodBody

Since: PMD 3.4

Priority: Medium (3)

Uncommented Empty Method Body finds instances where a method body does not contain statements, but there is no comment. By explicitly commenting empty method bodies it is easier to distinguish between intentional (commented) and unintentional empty methods.

This rule is defined by the following XPath expression:

    //MethodDeclaration/Block[count(*) = 0 and @containsComment = false()]

Example(s):

    public void doSomething() {
    }

Use this rule by referencing it:

    <rule ref="category/java/documentation.xml/UncommentedEmptyMethodBody" />