/*
 * Copyright (c) 2004 World Wide Web Consortium,
 *
 * (Massachusetts Institute of Technology, European Research Consortium for
 * Informatics and Mathematics, Keio University). All Rights Reserved. This
 * work is distributed under the W3C(r) Software License [1] in the hope that
 * it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231
 */

package org.w3c.dom;

/**
 * The <code>Text</code> interface inherits from <code>CharacterData</code> 
 * and represents the textual content (termed <a href='http://www.w3.org/TR/2004/REC-xml-20040204#syntax'>character data</a> in XML) of an <code>Element</code> or <code>Attr</code>. If there is no 
 * markup inside an element's content, the text is contained in a single 
 * object implementing the <code>Text</code> interface that is the only 
 * child of the element. If there is markup, it is parsed into the 
 * information items (elements, comments, etc.) and <code>Text</code> nodes 
 * that form the list of children of the element.
 * <p>When a document is first made available via the DOM, there is only one 
 * <code>Text</code> node for each block of text. Users may create adjacent 
 * <code>Text</code> nodes that represent the contents of a given element 
 * without any intervening markup, but should be aware that there is no way 
 * to represent the separations between these nodes in XML or HTML, so they 
 * will not (in general) persist between DOM editing sessions. The 
 * <code>Node.normalize()</code> method merges any such adjacent 
 * <code>Text</code> objects into a single node for each block of text.
 * <p> No lexical check is done on the content of a <code>Text</code> node 
 * and, depending on its position in the document, some characters must be 
 * escaped during serialization using character references; e.g. the 
 * characters "&lt;&amp;" if the textual content is part of an element or of 
 * an attribute, the character sequence "]]&gt;" when part of an element, 
 * the quotation mark character " or the apostrophe character ' when part of 
 * an attribute. 
 * <p>See also the <a href='http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407'>Document Object Model (DOM) Level 3 Core Specification</a>.
 */
public interface Text extends CharacterData {
    /**
     * Breaks this node into two nodes at the specified <code>offset</code>, 
     * keeping both in the tree as siblings. After being split, this node 
     * will contain all the content up to the <code>offset</code> point. A 
     * new node of the same type, which contains all the content at and 
     * after the <code>offset</code> point, is returned. If the original 
     * node had a parent node, the new node is inserted as the next sibling 
     * of the original node. When the <code>offset</code> is equal to the 
     * length of this node, the new node has no data.
     * @param offset The 16-bit unit offset at which to split, starting from 
     *   <code>0</code>.
     * @return The new node, of the same type as this node.
     * @exception DOMException
     *   INDEX_SIZE_ERR: Raised if the specified offset is negative or greater 
     *   than the number of 16-bit units in <code>data</code>.
     *   <br>NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
     */
    public Text splitText(int offset)
                          throws DOMException;

    /**
     * Returns whether this text node contains <a href='http://www.w3.org/TR/2004/REC-xml-infoset-20040204#infoitem.character'>
     * element content whitespace</a>, often abusively called "ignorable whitespace". The text node is 
     * determined to contain whitespace in element content during the load 
     * of the document or if validation occurs while using 
     * <code>Document.normalizeDocument()</code>.
     * @since DOM Level 3
     */
    public boolean isElementContentWhitespace();

    /**
     * Returns all text of <code>Text</code> nodes logically-adjacent text 
     * nodes to this node, concatenated in document order.
     * <br>For instance, in the example below <code>wholeText</code> on the 
     * <code>Text</code> node that contains "bar" returns "barfoo", while on 
     * the <code>Text</code> node that contains "foo" it returns "barfoo". 
     *
     * <pre>
     *                     +-----+
     *                     | &lt;p&gt; |
     *                     +-----+
     *                       /\
     *                      /  \
     *               /-----\    +-------+
     *               | bar |    | &amp;ent; |
     *               \-----/    +-------+
     *                              |
     *                              |
     *                           /-----\
     *                           | foo |
     *                           \-----/
     * </pre>
     * <em>Figure: barTextNode.wholeText value is "barfoo"</em>
     *
     * @since DOM Level 3
     */
    public String getWholeText();

    /**
     * Replaces the text of the current node and all logically-adjacent text 
     * nodes with the specified text. All logically-adjacent text nodes are 
     * removed including the current node unless it was the recipient of the 
     * replacement text.
     * <p>This method returns the node which received the replacement text. 
     * The returned node is:</p>
     * <ul>
     * <li><code>null</code>, when the replacement text is 
     * the empty string;
     * </li>
     * <li>the current node, except when the current node is 
     * read-only;
     * </li>
     * <li> a new <code>Text</code> node of the same type (
     * <code>Text</code> or <code>CDATASection</code>) as the current node 
     * inserted at the location of the replacement.
     * </li>
     * </ul>
     * <p>For instance, in the above example calling 
     * <code>replaceWholeText</code> on the <code>Text</code> node that 
     * contains "bar" with "yo" in argument results in the following:</p>
     *
     * <pre>
     *                     +-----+
     *                     | &lt;p&gt; |
     *                     +-----+
     *                        |
     *                        |
     *                     /-----\
     *                     | yo  |
     *                     \-----/
     * </pre>
     * <em>Figure: barTextNode.replaceWholeText("yo") modifies the
     * textual content of barTextNode with "yo"</em>
     *
     * <p>Where the nodes to be removed are read-only descendants of an 
     * <code>EntityReference</code>, the <code>EntityReference</code> must 
     * be removed instead of the read-only nodes. If any 
     * <code>EntityReference</code> to be removed has descendants that are 
     * not <code>EntityReference</code>, <code>Text</code>, or 
     * <code>CDATASection</code> nodes, the <code>replaceWholeText</code> 
     * method must fail before performing any modification of the document, 
     * raising a <code>DOMException</code> with the code 
     * <code>NO_MODIFICATION_ALLOWED_ERR</code>.</p>
     * <p>For instance, in the example below calling 
     * <code>replaceWholeText</code> on the <code>Text</code> node that 
     * contains "bar" fails, because the <code>EntityReference</code> node 
     * "ent" contains an <code>Element</code> node which cannot be removed.</p>
     * @param content The content of the replacing <code>Text</code> node.
     * @return The <code>Text</code> node created with the specified content.
     * @exception DOMException
     *   NO_MODIFICATION_ALLOWED_ERR: Raised if one of the <code>Text</code> 
     *   nodes being replaced is readonly.
     * @since DOM Level 3
     */
    public Text replaceWholeText(String content)
                                 throws DOMException;

}