Lecture 03 - Java_doc

8/11/2019 Lecture 03 - Java_doc

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JavaDoc


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Outline

What is JavaDoc?

JavaDoc CommentsJavaDoc TagsGenerating JavaDoc DocumentationReferences


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What is JavaDoc?

A software tool developed by Sun Microsystems forgenerating API documentation format from Java sourcecode augmented with special tags in the codes comments.An industry standard for documenting Java classes.

How does JavaDoc work?Instead of writing and maintaining separatedocumentation, the programmer writes formatted

comments in the Java code itself.Javadoc takes these comments and transforms theminto documentation.


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What is JavaDoc?

Many such systems exist that can be used for various

programming languages: Javadoc, Doxygen, Many of these can output in different formats:

HTML, RTF, PDF, LaTeX, manpages, HTML has many advantages:

Portable, browsable, adaptable

Doxygen is probably the most flexible of them all, as itcan generate documentation for various programminglanguages and generate output in various formats.


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What is JavaDoc?

Advantages:Program documentation process is coupled with the

programming processAutomated generation of documentation: less error-proneEase of generation of documentation

Ease of update of documentationShort code-to-documentation cycle: all programmers can bemade aware of others developments almost in real timeCan generate highly browsable documentation, accessible

electronically over the web (HTML)


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What is JavaDoc?

Disadvantages:There is a learning curve to learn how to use the tool,though it is minimalRequires dedication, or else the documentation will beobsolete or incomplete.


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What is JavaDoc?

Example:


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JavaDoc Comments

A JavaDoc comment begins with the /** marker and ends with the*/ marker. All the lines in the middle start with an asterisk lined upunder the first asterisk in the first line.

/*** This is a javadoc comment.*/

Because JavaDoc generates HTML files, any valid HTML can beembedded. A JavaDoc comment may be composed of multiplelines, for example:

/*** This is line one.* This is line two.** This is intended as a new paragraph.*/


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JavaDoc Comments

A JavaDoc comment is written in HTML and must precede aclass , field , constructor or method declaration.The * character is a marker used to make the JavaDoc commentsmore readable in the source file. They will not appear in thegenerated HTML documents. Since the blanks and tabs are alsoremoved, we need to use an HTML tag

to mark a new

paragraph as in: /**

* This is paragraph one.**

* This is paragraph two.**

* This is the last paragraph.

*/


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JavaDoc Comments

Another useful HTML marker is , which we can use toinclude a sample code in a JavaDoc comment. Any text betweenthe and markers will appear in a Courier font.

Example:


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JavaDoc Comments

The generated HTML will be:


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JavaDoc Comments

For the JavaDoc comments to be recognized as such by the javadoc tool, they must appear immediately before the class,interface, constructor, method, or data member declarations.If you put the JavaDoc comment for the class before the importstatements, it will be ignored .The first sentence is a summary sentence . This should be ashort description of the element described by the comment.

Note: JavaDoc does not provide a format for commenting elementswithin methods, i.e. the local variables and the computing goingon inside the methods. But you still can use the regular commentsmarks // or /*..*/, to comment this part of your program.


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JavaDoc Tags

Special tags can be embedded within the JavaDoc comments.These tags start with the at symbol @ .

JavaDoc tags must start at the beginning of a line.

Example:


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JavaDoc Tags

@authorUse this tag to create an author entry. You can have multiple@author tags. This tag is meaningful only for the class/interface JavaDoc comment.

@versionUse this tag to create a version entry. A JavaDoc comment maycontain at most one @version tag. Version normally refers to theversion of the software (such as the JDK) that contains thisfeature.

@seeUse this tag to add a hyperlinked "See Also" entry to the class.


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JavaDoc Tags

Example:


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JavaDoc Tags

Generated HTML:


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JavaDoc Tags

@paramUse this tag to add a parameter description for a method. This tag

contains two parts: the first is the name of the parameter and thesecond is the description. The description can be more than one line.

@param size the length of the passed array

@returnUse this tag to add a return type description for a method. This

tag is meaningful only if the methods return is non-void.

@return true if the array is empty; otherwise return false


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JavaDoc Tags

Example:


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JavaDoc Tags

Generated HTML:


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Generating JavaDoc DocumentationAfter adding the JavaDoc comments to the source files, we use the

javadoc command to generate the documentation.

We run the javadoc as we run javac or java tools.After the javadoc command, we provide the parameters, when themandatory ones are either the packages name or the source filename.

Example:In order to enforce JavaDoc to generate documentation for the completeGIPSY package, we write:

javadoc gipsy

In order to enforce JavaDoc to generate documentation for theJINITransportAgent.java file, to include the author and version tag and toinclude all the classes, attributes and methods we write:

javadoc -private -version -author JINITransportAgent.java


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Generating JavaDoc Documentation

Example:

The source java file with built in JavaDoc documentation:JINITransportAgent.java

The generated HTML documentation:JINITransportAgent.html
http://c/Documents%20and%20Settings/paquet/Desktop/javadoc/JINITransportAgent.javahttp://c/Documents%20and%20Settings/paquet/Desktop/javadoc/JINITA_doc/index.htmlhttp://c/Documents%20and%20Settings/paquet/Desktop/javadoc/JINITA_doc/index.htmlhttp://c/Documents%20and%20Settings/paquet/Desktop/javadoc/JINITransportAgent.java


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Sun Microsystems, How to Write Doc Comments for the Javadoc Tool ,http://java.sun.com/j2se/javadoc/writingdoccomments/index.html

Emil Vassev, DMS API Documentation, Concordia University, Montreal,Quebec, Canada, 2005

Wikipedia. Comparison of Documentation Generators.http://en.wikipedia.org/wiki/Comparison_of_documentation_generators

References