Xerces-J API: Interface Attr

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## org.w3c.dom
Interface Attr

All Known Implementing Classes:
  AttrImpl

public interface Attr
extends Node

The `Attr` interface represents an attribute in an `Element` object. Typically the allowable values for the attribute are defined in a document type definition.

`Attr` objects inherit the `Node` 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 `Node` attributes `parentNode`, `previousSibling`, and `nextSibling` have a `null` value for `Attr` 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, `Attr` nodes may not be immediate children of a `DocumentFragment`. However, they can be associated with `Element` nodes contained within a `DocumentFragment`. In short, users and implementors of the DOM need to be aware that `Attr` nodes have some things in common with other objects inheriting the `Node` interface, but they also are quite distinct.

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 `nodeValue` attribute on the `Attr` instance can also be used to retrieve the string version of the attribute's value(s).

In XML, where the value of an attribute can contain entity references, the child nodes of the `Attr` node may be either `Text` or `EntityReference` nodes (when these are in use; see the description of `EntityReference` for discussion). Because the DOM Core is not aware of attribute types, it treats all attribute values as simple strings, even if the DTD or schema declares them as having tokenized types.

See also the Document Object Model (DOM) Level 2 Core Specification.

Fields inherited from interface org.w3c.dom.Node
`ATTRIBUTE_NODE, CDATA_SECTION_NODE, COMMENT_NODE, DOCUMENT_FRAGMENT_NODE, DOCUMENT_NODE, DOCUMENT_TYPE_NODE, ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE, NOTATION_NODE, PROCESSING_INSTRUCTION_NODE, TEXT_NODE`

Method Summary
`java.lang.String` | `getName()` Returns the name of this attribute.
`Element` | `getOwnerElement()` The `Element` node this attribute is attached to or `null` if this attribute is not in use.
`boolean` | `getSpecified()` If this attribute was explicitly given a value in the original document, this is `true`; otherwise, it is `false`.
`java.lang.String` | `getValue()` On retrieval, the value of the attribute is returned as a string.
`void` | `setValue(java.lang.String value)`

Methods inherited from interface org.w3c.dom.Node
`appendChild, cloneNode, getAttributes, getChildNodes, getFirstChild, getLastChild, getLocalName, getNamespaceURI, getNextSibling, getNodeName, getNodeType, getNodeValue, getOwnerDocument, getParentNode, getPrefix, getPreviousSibling, hasAttributes, hasChildNodes, insertBefore, isSupported, normalize, removeChild, replaceChild, setNodeValue, setPrefix`

Method Detail

### getName

    public java.lang.String getName()

  Returns the name of this attribute.

### getSpecified

    public boolean getSpecified()

  If this attribute was explicitly given a value in the original document, this is `true`; otherwise, it is `false`. Note that the implementation is in charge of this attribute, not the user. If the user changes the value of the attribute (even if it ends up having the same value as the default value) then the `specified` flag is automatically flipped to `true`. To re-specify the attribute as the default value from the DTD, the user must delete the attribute. The implementation will then make a new attribute available with `specified` set to `false` and the default value (if one exists).
  In summary: If the attribute has an assigned value in the document then `specified` is `true`, and the value is the assigned value. If the attribute has no assigned value in the document and has a default value in the DTD, then `specified` is `false`, and the value is the default value in the DTD. If the attribute has no assigned value in the document and has a value of #IMPLIED in the DTD, then the attribute does not appear in the structure model of the document. If the `ownerElement` attribute is `null` (i.e. because it was just created or was set to `null` by the various removal and cloning operations) `specified` is `true`.

### getValue

    public java.lang.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 `getAttribute` on the `Element` interface.
  On setting, this creates a `Text` 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 `setAttribute` on the `Element` interface.
  Throws:
    DOMException - NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.

### setValue

    public void setValue(java.lang.String value)
                  throws DOMException

### getOwnerElement

    public Element getOwnerElement()

  The `Element` node this attribute is attached to or `null` if this attribute is not in use.
  Since:
    DOM Level 2

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