/*
 * @(#)Tag.java	1.12 02/10/15
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.javadoc;

/**
 * Represents a simple documentation tag, such as @since, @author, @version.
 * Given a tag (e.g. "@since 1.2"), holds tag name (e.g. "@since")
 * and tag text (e.g. "1.2").  Tags with structure or which require
 * special processing are handled by subclasses such as ParamTag 
 * (for @param), SeeTag (for @see and {@link}), and ThrowsTag
 * (for @throws).
 *
 * @author Robert Field
 * @author Atul M Dambalkar
 * @see SeeTag
 * @see ParamTag
 * @see ThrowsTag
 * @see SerialFieldTag
 * @see Doc#tags()
 *
 */
public interface Tag {

    /**
     * Return the name of this tag.  The name is the string 
     * starting with "@" that is used in a doc comment, such as 
     * <code>@return</code>.  For inline tags, such as 
     * <code>{@link}</code>, the curly brackets 
     * are not part of the name, so in this example the name 
     * would be simply <code>@link</code>.
     */
    String name();

    /**
     * Return the containing {@link Doc} of this Tag element.
     */
    Doc holder();

    /**
     * Return the kind of this tag.
     * similar or synonymous tags.  For most tags, 
     * <code>kind() == name()</code>
     * the following table lists those cases where there is more 
     * than one tag of a given kind:
     * <p>
     * <table border="1" cellpadding="4" cellspacing="0">
     * <tr><th><tt> kind()  </th>  <th><tt> name()      </th></tr>
     * <tr><td><tt> @throws </td>  <td><tt> @throws     </td></tr>
     * <tr><td><tt> @throws </td>  <td><tt> @exception  </td></tr>
     * <tr><td><tt> @see    </td>  <td><tt> @see        </td></tr>
     * <tr><td><tt> @see    </td>  <td><tt> @link       </td></tr>
     * <tr><td><tt> @see    </td>  <td><tt> @linkplain  </td></tr>
     * <tr><td><tt> @serial </td>  <td><tt> @serial     </td></tr>
     * <tr><td><tt> @serial </td>  <td><tt> @serialData </td></tr>
     * </table>
     */
    String kind();

    /**
     * Return the text of this tag, that is, portion beyond tag name.
     */
    String text();

    /**
     * Convert this object to a string.
     */
    String toString();

    /**
     * For a documentation comment with embedded <code>{@link}</code>
     * tags, return an array of <code>Tag</code> objects.  The entire
     * doc comment is broken down into strings separated by 
     * <code>{@link}</code> tags, where each successive element
     * of the array represents either a string or
     * <code>{@link}</code> tag, in order, from start to end.  
     * Each string is represented by a <code>Tag</code> object of 
     * name "Text", where {@link #text()} returns the string.  Each 
     * <code>{@link}</code> tag is represented by a 
     * {@link SeeTag} of name "@link" and kind "@see".
     * For example, given the following comment
     * tag:
     * <p>
     *  <code>This is a {@link Doc commentlabel} example.</code>
     * <p>
     * return an array of Tag objects:
     * <ul>
     *    <li> tags[0] is a {@link Tag} with name "Text" and text consisting
     *         of "This is a " 
     *    <li> tags[1] is a {@link SeeTag} with name "@link", referenced 
     *         class <code>Doc</code> and label "commentlabel"
     *    <li> tags[2] is a {@link Tag} with name "Text" and text consisting
     *         of " example." 
     * </ul>
     *
     * @return Tag[] array of tags
     * @see ParamTag
     * @see ThrowsTag
     */
    Tag[] inlineTags();

    /**
     * Return the first sentence of the comment as an array of tags. 
     * Includes inline tags 
     * (i.e. {@link <i>reference</i>} tags)  but not
     * block tags.  
     * Each section of plain text is represented as a {@link Tag} 
     * of kind "Text".
     * Inline tags are represented as a {@link SeeTag} of kind "@link".
     * If the locale is English language, the first sentence is 
     * determined by the rules described in the Java Language 
     * Specification (first version): "This sentence ends
     * at the first period that is followed by a blank, tab, or
     * line terminator or at the first tagline.", in 
     * addition a line will be terminated by paragraph and
     * section terminating HTML tags: <p>  </p>  <h1> 
     * <h2>  <h3> <h4>  <h5>  <h6> 
     * <hr>  <pre>  or </pre>.
     * If the locale is not English, the sentence end will be
     * determined by
     * {@link java.text.BreakIterator#getSentenceInstance(Locale) 
     * java.text.BreakIterator.getSentenceInstance(Locale)}.
     *
     * @return an array of {@link Tag} objects representing the 
     *         first sentence of the comment
     */
    Tag[] firstSentenceTags();

    /**
     * Return the source position of this tag.
     * @return the source position of this tag.
     */
    public SourcePosition position();
}