How to add reference to a method parameter in javadoc?

Question

Is there a way to add references to one or more of a method's parameters from the method documentation body? Something like:

/**
 * When {@paramref a} is null, we rely on b for the discombobulation.
 *
 * @param a this is one of the parameters
 * @param b another param
 */
void foo(String a, int b)
{...}

Abnormal

Answer 1

As far as I can tell after reading the docs for javadoc there is no such feature.

Don't use <code>foo</code> as recommended in other answers; you can use {@code foo}. This is especially good to know when you refer to a generic type such as {@code Iterator<String>} -- sure looks nicer than <code>Iterator&lt;String&gt;</code>, doesn't it!

Effluence

@code tag is described in Javadoc - Tag Descriptions. See Sample usage in JDK8 code. – Roscoe

How is it not possible to reference a method's own parameters within the docs of the method. Swing and a miss, Java! – Aeriell

Answer 2

The correct way of referring to a method parameter is like this:

Arvad

Not only does it answer the question, but it visually explains how to amend Javadoc with a parameter using an IDE such as Intellij. This will be useful for searchers who are looking for an answer. – Arvad

On Eclipse it doesn't work. But it's a nice answer nonetheless – Fusee

this should be deleted. imagine no longer exists. – Valediction

@Valediction Image looks fine, at least now. – Cromagnon

Try to refactor param name, intellij won't update this code blocks. – Uzzial

I just realized that the preview did not work for me since I was trying to refer one parameter from within the @param description of another instead of the javadoc body. – Tetzel

@Uzzial That's because this simply formats the text as code. It does not actually link to the parameter name in any way, unlike the C# paramref tag. – Gaillardia

Despite the pretty picture, ignore this answer and see the accepted answer from @kevin-bourrillion because it says to do the same thing but notes that it is only a workaround as no such feature exists (... and so you should not expect an actual link or for refactoring to update it etc.). – Potential

This is not an answer, it's a screenshot – Hypogeum

Answer 3

As you can see in the Java Source of the java.lang.String class:

/**
 * Allocates a new <code>String</code> that contains characters from
 * a subarray of the character array argument. The <code>offset</code>
 * argument is the index of the first character of the subarray and
 * the <code>count</code> argument specifies the length of the
 * subarray. The contents of the subarray are copied; subsequent
 * modification of the character array does not affect the newly
 * created string.
 *
 * @param      value    array that is the source of characters.
 * @param      offset   the initial offset.
 * @param      count    the length.
 * @exception  IndexOutOfBoundsException  if the <code>offset</code>
 *               and <code>count</code> arguments index characters outside
 *               the bounds of the <code>value</code> array.
 */
public String(char value[], int offset, int count) {
    if (offset < 0) {
        throw new StringIndexOutOfBoundsException(offset);
    }
    if (count < 0) {
        throw new StringIndexOutOfBoundsException(count);
    }
    // Note: offset or count might be near -1>>>1.
    if (offset > value.length - count) {
        throw new StringIndexOutOfBoundsException(offset + count);
    }

    this.value = new char[count];
    this.count = count;
    System.arraycopy(value, offset, this.value, 0, count);
}

Parameter references are surrounded by <code></code> tags, which means that the Javadoc syntax does not provide any way to do such a thing. (I think String.class is a good example of javadoc usage).

Ursine

The <code></code> tag is not referencing a specific parameter. It is formatting the word "String" into "code looking" text. – Lynwoodlynx

@Lynwoodlynx that's true for the first <code></code> tag, but further on in the javadoc they reference offset and count parameters surrounded by <code></code> tags – Yardstick

Answer 4

I guess you could write your own doclet or taglet to support this behaviour.

Taglet Overview

Doclet Overview

Handling

And make a pull request to javadoc :) – Burdine

Answer 5

Here is how it is written in Eclipse Temurin JDK 8 sources:

It looks like the only way is or {@code }, but it's not a link - it's just formatting.

Mcgannon

So.. other than under Params: section, where is x located in the javadoc description of println ? – Aparri

This is an incorrect answer! {@link #method(parameters)} works only for a link to other methods of the same class, not to the parameters of the same method, which was the question. – Nevermore