jdk.javadoc.doclet

The Doclet API provides an environment which, in conjunction with the Language Model API and Compiler Tree API, allows clients to inspect the source-level structures of programs and libraries, including API comments embedded in the source.

The standard doclet can be used to generate HTML-formatted documentation. It supports user-defined taglets, which can be used to generate customized output for user-defined tags in documentation comments.

Note: The declarations in this package supersede those in the older package com.sun.javadoc. For details on the mapping of old types to new types, see the Migration Guide.

Doclets are invoked by javadoc and this API can be used to write out program information to files. For example, the standard doclet is invoked by default, to generate HTML documentation.

The invocation is defined by the interface Doclet -- the run interface method, defines the entry point.

    public boolean run(DocletEnvironment environment)

The DocletEnvironment instance holds the environment that the doclet will be initialized with. From this environment all other information can be extracted, in the form of elements. One can further use the APIs and utilities described by Language Model API to query Elements and Types.

Terminology

Selected: An element is considered to be selected, if the selection controls allow it to be documented. (Note that synthetic elements are never selected.)
Specified: The set of elements specified by the user are considered to be specified elements. Specified elements provide the starting points for determining the included elements to be documented.
Included: An element is considered to be included, if it is specified if it contains a specified element, or it is enclosed in a specified element, and is selected. Included elements will be documented.

Options

Javadoc selection control can be specified with these options as follows:

--show-members:value and --show-types:value can be used to filter the members, with the following values:
- public -- considers only public elements
- protected -- considers public and protected elements
- package -- considers public, protected and package private elements
- private -- considers all elements
--show-packages:value "exported" or "all" can be used to consider only exported packages or all packages within a module.
--show-module-contents:value can be used to specify the level at module declarations could be documented. A value of "api" indicates API level documentation, and "all" indicates detailed documentation.

The following options can be used to specify the elements to be documented:

--module documents the specified modules.
--expand-requires:value expand the set of modules to be documented by including some or all of the modules dependencies. The value may be one of:
- transitive -- each module specified explicitly on the command line is expanded to include the closure of its transitive dependencies
- all -- each module specified explicitly on the command line is expanded to include the closure of its transitive dependencies, and also all of its direct dependencies
By default, only the specified modules will be considered, without expansion of the module dependencies.
packagenames can be used to specify packages.
-subpackages can be used to recursively load packages.
-exclude can be used exclude package directories.
sourcefilenames can be used to specify source file names.

Interactions with older options.

The new --show-* options provide a more detailed replacement for the older options -public, -protected, -package, -private. Alternatively, the older options can continue to be used as shorter forms for combinations of the new options, as described below:

Short form options mapping
Older option	Equivalent to these values with the new option
	`--show-members`	`--show-types`	`--show-packages`	`--show-module-contents`
`-public`	public	public	exported	api
`-protected`	protected	protected	exported	api
`-package`	package	package	all	all
`-private`	private	private	all	all

A qualified element name is one that has its package name prepended to it, such as java.lang.String. A non-qualified name has no package name, such as String.

Example

The following is an example doclet that displays information of a class and its members, supporting an option.

 // note imports deleted for clarity
 public class Example implements Doclet {
    Reporter reporter;
    @Override
    public void init(Locale locale, Reporter reporter) {
        reporter.print(Kind.NOTE, "Doclet using locale: " + locale);
        this.reporter = reporter;
    }

    public void printElement(DocTrees trees, Element e) {
        DocCommentTree docCommentTree = trees.getDocCommentTree(e);
        if (docCommentTree != null) {
            System.out.println("Element (" + e.getKind() + ": "
                    + e + ") has the following comments:");
            System.out.println("Entire body: " + docCommentTree.getFullBody());
            System.out.println("Block tags: " + docCommentTree.getBlockTags());
        }
    }

    @Override
    public boolean run(DocletEnvironment docEnv) {
        reporter.print(Kind.NOTE, "overviewfile: " + overviewfile);
        // get the DocTrees utility class to access document comments
        DocTrees docTrees = docEnv.getDocTrees();

        // location of an element in the same directory as overview.html
        try {
            Element e = ElementFilter.typesIn(docEnv.getSpecifiedElements()).iterator().next();
            DocCommentTree docCommentTree
                    = docTrees.getDocCommentTree(e, overviewfile);
            if (docCommentTree != null) {
                System.out.println("Overview html: " + docCommentTree.getFullBody());
            }
        } catch (IOException missing) {
            reporter.print(Kind.ERROR, "No overview.html found.");
        }

        for (TypeElement t : ElementFilter.typesIn(docEnv.getIncludedElements())) {
            System.out.println(t.getKind() + ":" + t);
            for (Element e : t.getEnclosedElements()) {
                printElement(docTrees, e);
            }
        }
        return true;
    }

    @Override
    public String getName() {
        return "Example";
    }

    private String overviewfile;

    @Override
    public Set<? extends Option> getSupportedOptions() {
        Option[] options = {
            new Option() {
                private final List<String> someOption = Arrays.asList(
                        "-overviewfile",
                        "--overview-file",
                        "-o"
                );

                @Override
                public int getArgumentCount() {
                    return 1;
                }

                @Override
                public String getDescription() {
                    return "an option with aliases";
                }

                @Override
                public Option.Kind getKind() {
                    return Option.Kind.STANDARD;
                }

                @Override
                public List<String> getNames() {
                    return someOption;
                }

                @Override
                public String getParameters() {
                    return "file";
                }

                @Override
                public boolean process(String opt, List<String> arguments) {
                    overviewfile = arguments.get(0);
                    return true;
                }
            }
        };
        return new HashSet<>(Arrays.asList(options));
    }

    @Override
    public SourceVersion getSupportedSourceVersion() {
        // support the latest release
        return SourceVersion.latest();
    }
 }

This doclet can be invoked with a command line, such as:

     javadoc -doclet Example \
       -overviewfile overview.html \
       -sourcepath source-location \
       source-location/Example.java

Migration Guide

Many of the types in the old com.sun.javadoc API do not have equivalents in this package. Instead, types in the javax.lang.model and com.sun.source APIs are used instead.

The following table gives a guide to the mapping from old types to their replacements. In some cases, there is no direct equivalent.

Guide for mapping old types to new types
Old Type	New Type
AnnotatedType	javax.lang.model.type.Type
AnnotationDesc	javax.lang.model.element.AnnotationMirror
AnnotationDesc.ElementValuePair	javax.lang.model.element.AnnotationValue
AnnotationTypeDoc	javax.lang.model.element.TypeElement
AnnotationTypeElementDoc	javax.lang.model.element.ExecutableElement
AnnotationValue	javax.lang.model.element.AnnotationValue
ClassDoc	javax.lang.model.element.TypeElement
ConstructorDoc	javax.lang.model.element.ExecutableElement
Doc	javax.lang.model.element.Element
DocErrorReporter	jdk.javadoc.doclet.Reporter
Doclet	jdk.javadoc.doclet.Doclet
ExecutableMemberDoc	javax.lang.model.element.ExecutableElement
FieldDoc	javax.lang.model.element.VariableElement
LanguageVersion	javax.lang.model.SourceVersion
MemberDoc	javax.lang.model.element.Element
MethodDoc	javax.lang.model.element.ExecutableElement
PackageDoc	javax.lang.model.element.PackageElement
Parameter	javax.lang.model.element.VariableElement
ParameterizedType	javax.lang.model.type.DeclaredType
ParamTag	com.sun.source.doctree.ParamTree
ProgramElementDoc	javax.lang.model.element.Element
RootDoc	jdk.javadoc.doclet.DocletEnvironment
SeeTag	com.sun.source.doctree.LinkTree com.sun.source.doctree.SeeTree
SerialFieldTag	com.sun.source.doctree.SerialFieldTree
SourcePosition	com.sun.source.util.SourcePositions
Tag	com.sun.source.doctree.DocTree
ThrowsTag	com.sun.source.doctree.ThrowsTree
Type	javax.lang.model.type.Type
TypeVariable	javax.lang.model.type.TypeVariable
WildcardType	javax.lang.model.type.WildcardType

Since:: 9
See Also:: Doclet, DocletEnvironment

Interface Summary
Interface	Description
Doclet	The user doclet must implement this interface, as described in the package description.
Doclet.Option	An encapsulation of option name, aliases, parameters and descriptions as used by the Doclet.
DocletEnvironment	Represents the operating environment of a single invocation of the doclet.
Reporter	This interface provides error, warning and notice reporting.
Taglet	The interface for a custom taglet supported by doclets such as the `standard doclet`.

Class Summary
Class Description

StandardDoclet
This doclet generates HTML-formatted documentation for the specified modules, packages and types.
Enum Summary
Enum Description

Doclet.Option.Kind
The kind of an option.

DocletEnvironment.ModuleMode

Taglet.Location
The kind of location in which a tag may be used.

Enum	Description
Doclet.Option.Kind	The kind of an option.
DocletEnvironment.ModuleMode
Taglet.Location	The kind of location in which a tag may be used.

Package jdk.javadoc.doclet

Terminology

Options

Interactions with older options.

Example

Migration Guide