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org.w3c.dom
Interface Element

All Superinterfaces:
Node
All Known Implementing Classes:
DomElement
public interface Element
extends Node

The Element interface represents an element in an HTML or XML document. Elements may have attributes associated with them; since the Element interface inherits from Node, the generic Node interface attribute attributes may be used to retrieve the set of all attributes for an element. There are methods on the Element interface to retrieve either an Attr object by name or an attribute value by name. In XML, where an attribute value may contain entity references, an Attr object should be retrieved to examine the possibly fairly complex sub-tree representing the attribute value. On the other hand, in HTML, where all attributes have simple string values, methods to directly access an attribute value can safely be used as a convenience.In DOM Level 2, the method normalize is inherited from the Node interface where it was moved.

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 getAttribute(java.lang.String name)
          Retrieves an attribute value by name.
 Attr getAttributeNode(java.lang.String name)
          Retrieves an attribute node by name.
 Attr getAttributeNodeNS(java.lang.String namespaceURI, java.lang.String localName)
          Retrieves an Attr node by local name and namespace URI.
 java.lang.String getAttributeNS(java.lang.String namespaceURI, java.lang.String localName)
          Retrieves an attribute value by local name and namespace URI.
 NodeList getElementsByTagName(java.lang.String name)
          Returns a NodeList of all descendant Elements with a given tag name, in the order in which they are encountered in a preorder traversal of this Element tree.
 NodeList getElementsByTagNameNS(java.lang.String namespaceURI, java.lang.String localName)
          Returns a NodeList of all the descendant Elements with a given local name and namespace URI in the order in which they are encountered in a preorder traversal of this Element tree.
 java.lang.String getTagName()
          The name of the element.
 boolean hasAttribute(java.lang.String name)
          Returns true when an attribute with a given name is specified on this element or has a default value, false otherwise.
 boolean hasAttributeNS(java.lang.String namespaceURI, java.lang.String localName)
          Returns true when an attribute with a given local name and namespace URI is specified on this element or has a default value, false otherwise.
 void removeAttribute(java.lang.String name)
          Removes an attribute by name.
 Attr removeAttributeNode(Attr oldAttr)
          Removes the specified attribute node.
 void removeAttributeNS(java.lang.String namespaceURI, java.lang.String localName)
          Removes an attribute by local name and namespace URI.
 void setAttribute(java.lang.String name, java.lang.String value)
          Adds a new attribute.
 Attr setAttributeNode(Attr newAttr)
          Adds a new attribute node.
 Attr setAttributeNodeNS(Attr newAttr)
          Adds a new attribute.
 void setAttributeNS(java.lang.String namespaceURI, java.lang.String qualifiedName, java.lang.String value)
          Adds a new attribute.
 
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

getTagName

public java.lang.String getTagName()
The name of the element. For example, in: 
 <elementExample 
 id="demo"> ... </elementExample> ,
tagName has the value "elementExample". Note that this is case-preserving in XML, as are all of the operations of the DOM. The HTML DOM returns the tagName of an HTML element in the canonical uppercase form, regardless of the case in the source HTML document.

getAttribute

public java.lang.String getAttribute(java.lang.String name)
Retrieves an attribute value by name.
Parameters:
nameThe - name of the attribute to retrieve.
Returns:
The Attr value as a string, or the empty string if that attribute does not have a specified or default value.

setAttribute

public void setAttribute(java.lang.String name,
                         java.lang.String value)
                  throws DOMException
Adds a new attribute. If an attribute with that name is already present in the element, its value is changed to be that of the value parameter. This value is a simple string; it is not parsed as it is being set. So any markup (such as syntax to be recognized as an entity reference) is treated as literal text, and needs to be appropriately escaped by the implementation when it is written out. In order to assign an attribute value that contains entity references, the user must create an Attr node plus any Text and EntityReference nodes, build the appropriate subtree, and use setAttributeNode to assign it as the value of an attribute.
To set an attribute with a qualified name and namespace URI, use the setAttributeNS method.
Parameters:
nameThe - name of the attribute to create or alter.
valueValue - to set in string form.
Throws:
DOMException - INVALID_CHARACTER_ERR: Raised if the specified name contains an illegal character.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

removeAttribute

public void removeAttribute(java.lang.String name)
                     throws DOMException
Removes an attribute by name. If the removed attribute is known to have a default value, an attribute immediately appears containing the default value as well as the corresponding namespace URI, local name, and prefix when applicable.
To remove an attribute by local name and namespace URI, use the removeAttributeNS method.
Parameters:
nameThe - name of the attribute to remove.
Throws:
DOMException - NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

getAttributeNode

public Attr getAttributeNode(java.lang.String name)
Retrieves an attribute node by name.
To retrieve an attribute node by qualified name and namespace URI, use the getAttributeNodeNS method.
Parameters:
nameThe - name (nodeName) of the attribute to retrieve.
Returns:
The Attr node with the specified name ( nodeName) or null if there is no such attribute.

setAttributeNode

public Attr setAttributeNode(Attr newAttr)
                      throws DOMException
Adds a new attribute node. If an attribute with that name ( nodeName) is already present in the element, it is replaced by the new one.
To add a new attribute node with a qualified name and namespace URI, use the setAttributeNodeNS method.
Parameters:
newAttrThe - Attr node to add to the attribute list.
Returns:
If the newAttr attribute replaces an existing attribute, the replaced Attr node is returned, otherwise null is returned.
Throws:
DOMException - WRONG_DOCUMENT_ERR: Raised if newAttr was created from a different document than the one that created the element.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
INUSE_ATTRIBUTE_ERR: Raised if newAttr is already an attribute of another Element object. The DOM user must explicitly clone Attr nodes to re-use them in other elements.

removeAttributeNode

public Attr removeAttributeNode(Attr oldAttr)
                         throws DOMException
Removes the specified attribute node. If the removed Attr has a default value it is immediately replaced. The replacing attribute has the same namespace URI and local name, as well as the original prefix, when applicable.
Parameters:
oldAttrThe - Attr node to remove from the attribute list.
Returns:
The Attr node that was removed.
Throws:
DOMException - NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NOT_FOUND_ERR: Raised if oldAttr is not an attribute of the element.

getElementsByTagName

public NodeList getElementsByTagName(java.lang.String name)
Returns a NodeList of all descendant Elements with a given tag name, in the order in which they are encountered in a preorder traversal of this Element tree.
Parameters:
nameThe - name of the tag to match on. The special value "*" matches all tags.
Returns:
A list of matching Element nodes.

getAttributeNS

public java.lang.String getAttributeNS(java.lang.String namespaceURI,
                                       java.lang.String localName)
Retrieves an attribute value by local name and namespace URI. HTML-only DOM implementations do not need to implement this method.
Parameters:
namespaceURIThe - namespace URI of the attribute to retrieve.
localNameThe - local name of the attribute to retrieve.
Returns:
The Attr value as a string, or the empty string if that attribute does not have a specified or default value.
Since:
DOM Level 2

setAttributeNS

public void setAttributeNS(java.lang.String namespaceURI,
                           java.lang.String qualifiedName,
                           java.lang.String value)
                    throws DOMException
Adds a new attribute. If an attribute with the same local name and namespace URI is already present on the element, its prefix is changed to be the prefix part of the qualifiedName, and its value is changed to be the value parameter. This value is a simple string; it is not parsed as it is being set. So any markup (such as syntax to be recognized as an entity reference) is treated as literal text, and needs to be appropriately escaped by the implementation when it is written out. In order to assign an attribute value that contains entity references, the user must create an Attr node plus any Text and EntityReference nodes, build the appropriate subtree, and use setAttributeNodeNS or setAttributeNode to assign it as the value of an attribute.
HTML-only DOM implementations do not need to implement this method.
Parameters:
namespaceURIThe - namespace URI of the attribute to create or alter.
qualifiedNameThe - qualified name of the attribute to create or alter.
valueThe - value to set in string form.
Throws:
DOMException - INVALID_CHARACTER_ERR: Raised if the specified qualified name contains an illegal character.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NAMESPACE_ERR: Raised if the qualifiedName is malformed, if the qualifiedName has a prefix and the namespaceURI is null, if the qualifiedName has a prefix that is "xml" and the namespaceURI is different from " http://www.w3.org/XML/1998/namespace", or if the qualifiedName is "xmlns" and the namespaceURI is different from " http://www.w3.org/2000/xmlns/".
Since:
DOM Level 2

removeAttributeNS

public void removeAttributeNS(java.lang.String namespaceURI,
                              java.lang.String localName)
                       throws DOMException
Removes an attribute by local name and namespace URI. If the removed attribute has a default value it is immediately replaced. The replacing attribute has the same namespace URI and local name, as well as the original prefix.
HTML-only DOM implementations do not need to implement this method.
Parameters:
namespaceURIThe - namespace URI of the attribute to remove.
localNameThe - local name of the attribute to remove.
Throws:
DOMException - NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
Since:
DOM Level 2

getAttributeNodeNS

public Attr getAttributeNodeNS(java.lang.String namespaceURI,
                               java.lang.String localName)
Retrieves an Attr node by local name and namespace URI. HTML-only DOM implementations do not need to implement this method.
Parameters:
namespaceURIThe - namespace URI of the attribute to retrieve.
localNameThe - local name of the attribute to retrieve.
Returns:
The Attr node with the specified attribute local name and namespace URI or null if there is no such attribute.
Since:
DOM Level 2

setAttributeNodeNS

public Attr setAttributeNodeNS(Attr newAttr)
                        throws DOMException
Adds a new attribute. If an attribute with that local name and that namespace URI is already present in the element, it is replaced by the new one.
HTML-only DOM implementations do not need to implement this method.
Parameters:
newAttrThe - Attr node to add to the attribute list.
Returns:
If the newAttr attribute replaces an existing attribute with the same local name and namespace URI, the replaced Attr node is returned, otherwise null is returned.
Throws:
DOMException - WRONG_DOCUMENT_ERR: Raised if newAttr was created from a different document than the one that created the element.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
INUSE_ATTRIBUTE_ERR: Raised if newAttr is already an attribute of another Element object. The DOM user must explicitly clone Attr nodes to re-use them in other elements.
Since:
DOM Level 2

getElementsByTagNameNS

public NodeList getElementsByTagNameNS(java.lang.String namespaceURI,
                                       java.lang.String localName)
Returns a NodeList of all the descendant Elements with a given local name and namespace URI in the order in which they are encountered in a preorder traversal of this Element tree.
HTML-only DOM implementations do not need to implement this method.
Parameters:
namespaceURIThe - namespace URI of the elements to match on. The special value "*" matches all namespaces.
localNameThe - local name of the elements to match on. The special value "*" matches all local names.
Returns:
A new NodeList object containing all the matched Elements.
Since:
DOM Level 2

hasAttribute

public boolean hasAttribute(java.lang.String name)
Returns true when an attribute with a given name is specified on this element or has a default value, false otherwise.
Parameters:
nameThe - name of the attribute to look for.
Returns:
true if an attribute with the given name is specified on this element or has a default value, false otherwise.
Since:
DOM Level 2

hasAttributeNS

public boolean hasAttributeNS(java.lang.String namespaceURI,
                              java.lang.String localName)
Returns true when an attribute with a given local name and namespace URI is specified on this element or has a default value, false otherwise. HTML-only DOM implementations do not need to implement this method.
Parameters:
namespaceURIThe - namespace URI of the attribute to look for.
localNameThe - local name of the attribute to look for.
Returns:
true if an attribute with the given local name and namespace URI is specified or has a default value on this element, false otherwise.
Since:
DOM Level 2
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Source code is GPL'd in the JAXP subproject at http://savannah.gnu.org/projects/classpathx
This documentation was derived from that source code on 2001-07-12.

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