/*
* 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>Attr</code> interface represents an attribute in an
* <code>Element</code> object. Typically the allowable values for the
* attribute are defined in a schema associated with the document.
* <p><code>Attr</code> objects inherit the <code>Node</code> interface, but
* since they are not actually child nodes of the element they describe, the
* DOM does not consider them part of the document tree. Thus, the
* <code>Node</code> attributes <code>parentNode</code>,
* <code>previousSibling</code>, and <code>nextSibling</code> have a
* <code>null</code> value for <code>Attr</code> objects. The DOM takes the
* view that attributes are properties of elements rather than having a
* separate identity from the elements they are associated with; this should
* make it more efficient to implement such features as default attributes
* associated with all elements of a given type. Furthermore,
* <code>Attr</code> nodes may not be immediate children of a
* <code>DocumentFragment</code>. However, they can be associated with
* <code>Element</code> nodes contained within a
* <code>DocumentFragment</code>. In short, users and implementors of the
* DOM need to be aware that <code>Attr</code> nodes have some things in
* common with other objects inheriting the <code>Node</code> interface, but
* they also are quite distinct.
* <p>The attribute's effective value is determined as follows: if this
* attribute has been explicitly assigned any value, that value is the
* attribute's effective value; otherwise, if there is a declaration for
* this attribute, and that declaration includes a default value, then that
* default value is the attribute's effective value; otherwise, the
* attribute does not exist on this element in the structure model until it
* has been explicitly added. Note that the <code>Node.nodeValue</code>
* attribute on the <code>Attr</code> instance can also be used to retrieve
* the string version of the attribute's value(s).
* <p> If the attribute was not explicitly given a value in the instance
* document but has a default value provided by the schema associated with
* the document, an attribute node will be created with
* <code>specified</code> set to <code>false</code>. Removing attribute
* nodes for which a default value is defined in the schema generates a new
* attribute node with the default value and <code>specified</code> set to
* <code>false</code>. If validation occurred while invoking
* <code>Document.normalizeDocument()</code>, attribute nodes with
* <code>specified</code> equals to <code>false</code> are recomputed
* according to the default attribute values provided by the schema. If no
* default value is associate with this attribute in the schema, the
* attribute node is discarded.
* <p>In XML, where the value of an attribute can contain entity references,
* the child nodes of the <code>Attr</code> node may be either
* <code>Text</code> or <code>EntityReference</code> nodes (when these are
* in use; see the description of <code>EntityReference</code> for
* discussion).
* <p>The DOM Core represents all attribute values as simple strings, even if
* the DTD or schema associated with the document declares them of some
* specific type such as tokenized.
* <p>The way attribute value normalization is performed by the DOM
* implementation depends on how much the implementation knows about the
* schema in use. Typically, the <code>value</code> and
* <code>nodeValue</code> attributes of an <code>Attr</code> node initially
* returns the normalized value given by the parser. It is also the case
* after <code>Document.normalizeDocument()</code> is called (assuming the
* right options have been set). But this may not be the case after
* mutation, independently of whether the mutation is performed by setting
* the string value directly or by changing the <code>Attr</code> child
* nodes. In particular, this is true when <a href='http://www.w3.org/TR/2004/REC-xml-20040204#dt-charref'>character
* references</a> are involved, given that they are not represented in the DOM and they
* impact attribute value normalization. On the other hand, if the
* implementation knows about the schema in use when the attribute value is
* changed, and it is of a different type than CDATA, it may normalize it
* again at that time. This is especially true of specialized DOM
* implementations, such as SVG DOM implementations, which store attribute
* values in an internal form different from a string.
* <p>The following table gives some examples of the relations between the
* attribute value in the original document (parsed attribute), the value as
* exposed in the DOM, and the serialization of the value:
* <table border='1' cellpadding='3'>
* <tr>
* <th>Examples</th>
* <th>Parsed
* attribute value</th>
* <th>Initial <code>Attr.value</code></th>
* <th>Serialized attribute value</th>
* </tr>
* <tr>
* <td valign='top' rowspan='1' colspan='1'>
* Character reference</td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"x²=5"</pre>
* </td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"x\u00b2=5"</pre>
* </td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"x²=5"</pre>
* </td>
* </tr>
* <tr>
* <td valign='top' rowspan='1' colspan='1'>Built-in
* character entity</td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"y<6"</pre>
* </td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"y<6"</pre>
* </td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"y<6"</pre>
* </td>
* </tr>
* <tr>
* <td valign='top' rowspan='1' colspan='1'>Literal newline between</td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>
* "x=5 y=6"</pre>
* </td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"x=5 y=6"</pre>
* </td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"x=5 y=6"</pre>
* </td>
* </tr>
* <tr>
* <td valign='top' rowspan='1' colspan='1'>Normalized newline between</td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"x=5
* y=6"</pre>
* </td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"x=5 y=6"</pre>
* </td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>"x=5 y=6"</pre>
* </td>
* </tr>
* <tr>
* <td valign='top' rowspan='1' colspan='1'>Entity <code>e</code> with literal newline</td>
* <td valign='top' rowspan='1' colspan='1'>
* <pre>
* <!ENTITY e '... ...'> [...]> "x=5&e;y=6"</pre>
* </td>
* <td valign='top' rowspan='1' colspan='1'><em>Dependent on Implementation and Load Options</em></td>
* <td valign='top' rowspan='1' colspan='1'><em>Dependent on Implementation and Load/Save Options</em></td>
* </tr>
* </table>
* <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 Attr extends Node {
/**
* Returns the name of this attribute. If <code>Node.localName</code> is
* different from <code>null</code>, this attribute is a qualified name.
*/
public String getName();
/**
* <code>True</code> if this attribute was explicitly given a value in
* the instance document, <code>false</code> otherwise. If the
* application changed the value of this attribute node (even if it ends
* up having the same value as the default value) then it is set to
* <code>true</code>. The implementation may handle attributes with
* default values from other schemas similarly but applications should
* use <code>Document.normalizeDocument()</code> to guarantee this
* information is up-to-date.
*/
public boolean getSpecified();
/**
* On retrieval, the value of the attribute is returned as a string.
* Character and general entity references are replaced with their
* values. See also the method <code>getAttribute</code> on the
* <code>Element</code> interface.
* <br>On setting, this creates a <code>Text</code> node with the unparsed
* contents of the string, i.e. any characters that an XML processor
* would recognize as markup are instead treated as literal text. See
* also the method <code>Element.setAttribute()</code>.
* <br> Some specialized implementations, such as some [<a href='http://www.w3.org/TR/2003/REC-SVG11-20030114/'>SVG 1.1</a>]
* implementations, may do normalization automatically, even after
* mutation; in such case, the value on retrieval may differ from the
* value on setting.
*/
public String getValue();
/**
* On retrieval, the value of the attribute is returned as a string.
* Character and general entity references are replaced with their
* values. See also the method <code>getAttribute</code> on the
* <code>Element</code> interface.
* <br>On setting, this creates a <code>Text</code> node with the unparsed
* contents of the string, i.e. any characters that an XML processor
* would recognize as markup are instead treated as literal text. See
* also the method <code>Element.setAttribute()</code>.
* <br> Some specialized implementations, such as some [<a href='http://www.w3.org/TR/2003/REC-SVG11-20030114/'>SVG 1.1</a>]
* implementations, may do normalization automatically, even after
* mutation; in such case, the value on retrieval may differ from the
* value on setting.
* @exception DOMException
* NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.
*/
public void setValue(String value)
throws DOMException;
/**
* The <code>Element</code> node this attribute is attached to or
* <code>null</code> if this attribute is not in use.
* @since DOM Level 2
*/
public Element getOwnerElement();
/**
* The type information associated with this attribute. While the type
* information contained in this attribute is guarantee to be correct
* after loading the document or invoking
* <code>Document.normalizeDocument()</code>, <code>schemaTypeInfo</code>
* may not be reliable if the node was moved.
* @since DOM Level 3
*/
public TypeInfo getSchemaTypeInfo();
/**
* Returns whether this attribute is known to be of type ID (i.e. to
* contain an identifier for its owner element) or not. When it is and
* its value is unique, the <code>ownerElement</code> of this attribute
* can be retrieved using the method <code>Document.getElementById</code>
* . The implementation could use several ways to determine if an
* attribute node is known to contain an identifier:
* <ul>
* <li> If validation
* occurred using an XML Schema [<a href='http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/'>XML Schema Part 1</a>]
* while loading the document or while invoking
* <code>Document.normalizeDocument()</code>, the post-schema-validation
* infoset contributions (PSVI contributions) values are used to
* determine if this attribute is a schema-determined ID attribute using
* the <a href='http://www.w3.org/TR/2003/REC-xptr-framework-20030325/#term-sdi'>
* schema-determined ID</a> definition in [<a href='http://www.w3.org/TR/2003/REC-xptr-framework-20030325/'>XPointer</a>]
* .
* </li>
* <li> If validation occurred using a DTD while loading the document or
* while invoking <code>Document.normalizeDocument()</code>, the infoset <b>[type definition]</b> value is used to determine if this attribute is a DTD-determined ID
* attribute using the <a href='http://www.w3.org/TR/2003/REC-xptr-framework-20030325/#term-ddi'>
* DTD-determined ID</a> definition in [<a href='http://www.w3.org/TR/2003/REC-xptr-framework-20030325/'>XPointer</a>]
* .
* </li>
* <li> from the use of the methods <code>Element.setIdAttribute()</code>,
* <code>Element.setIdAttributeNS()</code>, or
* <code>Element.setIdAttributeNode()</code>, i.e. it is an
* user-determined ID attribute;
* <p ><b>Note:</b> XPointer framework (see section 3.2 in [<a href='http://www.w3.org/TR/2003/REC-xptr-framework-20030325/'>XPointer</a>]
* ) consider the DOM user-determined ID attribute as being part of the
* XPointer externally-determined ID definition.
* </li>
* <li> using mechanisms that
* are outside the scope of this specification, it is then an
* externally-determined ID attribute. This includes using schema
* languages different from XML schema and DTD.
* </li>
* </ul>
* <br> If validation occurred while invoking
* <code>Document.normalizeDocument()</code>, all user-determined ID
* attributes are reset and all attribute nodes ID information are then
* reevaluated in accordance to the schema used. As a consequence, if
* the <code>Attr.schemaTypeInfo</code> attribute contains an ID type,
* <code>isId</code> will always return true.
* @since DOM Level 3
*/
public boolean isId();
}