Class AttrImpl

java.lang.Object
org.htmlunit.cyberneko.xerces.dom.NodeImpl
org.htmlunit.cyberneko.xerces.dom.AttrImpl
All Implemented Interfaces:
Cloneable, Attr, EventTarget, Node, NodeList, TypeInfo
Direct Known Subclasses:
AttrNSImpl
public class AttrImpl extends NodeImpl implements Attr, TypeInfo
Attribute represents an XML-style attribute of an Element. Typically, the allowable values are controlled by its declaration in the Document Type Definition (DTD) governing this kind of document.

If the attribute has not been explicitly assigned a value, but has been declared in the DTD, it will exist and have that default. Only if neither the document nor the DTD specifies a value will the Attribute really be considered absent and have no value; in that case, querying the attribute will return null.

Attributes may have multiple children that contain their data. (XML allows attributes to contain entity references, and tokenized attribute types such as NMTOKENS may have a child for each token.) For convenience, the Attribute object's getValue() method returns the string version of the attribute's value.

Attributes are not children of the Elements they belong to, in the usual sense, and have no valid Parent reference. However, the spec says they _do_ belong to a specific Element, and an INUSE exception is to be thrown if the user attempts to explicitly share them between elements.

Note that Elements do not permit attributes to appear to be shared (see the INUSE exception), so this object's mutability is officially not an issue.

Note: The ownerNode attribute is used to store the Element the Attr node is associated with. Attr nodes do not have parent nodes. Besides, the getOwnerElement() method can be used to get the element node this attribute is associated with.

AttrImpl does not support Namespaces. AttrNSImpl, which inherits from it, does.

AttrImpl used to inherit from ParentNode. It now directly inherits from NodeImpl and provide its own implementation of the ParentNode's behavior. The reason is that we now try and avoid to always create a Text node to hold the value of an attribute. The DOM spec requires it, so we still have to do it in case getFirstChild() is called for instance. The reason attribute values are stored as a list of nodes is so that they can carry more than a simple string. They can also contain EntityReference nodes. However, most of the times people only have a single string that they only set and get through Element.set/getAttribute or Attr.set/getValue. In this new version, the Attr node has a value pointer which can either be the String directly or a pointer to the first ChildNode. A flag tells which one it currently is. Note that while we try to stick with the direct String as much as possible once we've switched to a node there is no going back. This is because we have no way to know whether the application keeps referring to the node we once returned.

The gain in memory varies on the density of attributes in the document. But in the tests I've run I've seen up to 12% of memory gain. And the good thing is that it also leads to a slight gain in speed because we allocate fewer objects! I mean, that's until we have to actually create the node...

To avoid too much duplicated code, I got rid of ParentNode and renamed ChildAndParentNode, which I never really liked, to ParentNode for simplicity, this doesn't make much of a difference in memory usage because there are only very few objects that are only a Parent. This is only true now because AttrImpl now inherits directly from NodeImpl and has its own implementation of the ParentNode's node behavior. So there is still some duplicated code there.

This class doesn't directly support mutation events, however, it notifies the document when mutations are performed so that the document class do so.

WARNING: Some of the code here is partially duplicated in ParentNode, be careful to keep these two classes in sync!

See Also:

  • Field Details

    • DTD_URI

      protected static final String DTD_URI
      DTD namespace.
      See Also:

    • value_

      private Object value_
      This can either be a String or the first child node.

    • name

      protected String name
      Attribute name.

    • type

      protected String type
      Type information

  • Constructor Details

    • AttrImpl

      protected AttrImpl(CoreDocumentImpl ownerDocument, String name)
      Attribute has no public constructor. Please use the factory method in the Document class.
      Parameters:
      ownerDocument - the owner document
      name - the name

  • Method Details

    • rename

      void rename(String name)

    • makeChildNode

      protected void makeChildNode()

    • setOwnerDocument

      protected void setOwnerDocument(CoreDocumentImpl doc)
      NON-DOM set the ownerDocument of this node and its children
      Overrides:
      setOwnerDocument in class NodeImpl

    • isId

      public boolean isId()
      DOM Level 3: isId
      Specified by:
      isId in interface Attr

    • cloneNode

      public Node cloneNode(boolean deep)
      Description copied from class: NodeImpl
      Returns a duplicate of a given node. You can consider this a generic "copy constructor" for nodes. The newly returned object should be completely independent of the source object's subtree, so changes in one after the clone has been made will not affect the other.

      Note: since we never have any children deep is meaningless here, ParentNode overrides this behavior.

      Specified by:
      cloneNode in interface Node
      Overrides:
      cloneNode in class NodeImpl
      See Also:

    • getNodeType

      public short getNodeType()
      A short integer indicating what type of node this is. The named constants for this value are defined in the org.w3c.dom.Node interface.
      Specified by:
      getNodeType in interface Node
      Specified by:
      getNodeType in class NodeImpl

    • getNodeName

      public String getNodeName()
      the name of this node.
      Specified by:
      getNodeName in interface Node
      Specified by:
      getNodeName in class NodeImpl

    • setNodeValue

      public void setNodeValue(String value) throws DOMException
      Sets the node value. Implicit in the rerouting of getNodeValue to getValue is the need to redefine setNodeValue, for symmetry's sake. Note that since we're explicitly providing a value, Specified should be set true.... even if that value equals the default.
      Specified by:
      setNodeValue in interface Node
      Overrides:
      setNodeValue in class NodeImpl
      Throws:
      DOMException - NO_MODIFICATION_ALLOWED_ERR

    • getTypeName

      public String getTypeName()
      Specified by:
      getTypeName in interface TypeInfo

    • getTypeNamespace

      public String getTypeNamespace()
      Specified by:
      getTypeNamespace in interface TypeInfo

    • getSchemaTypeInfo

      public TypeInfo getSchemaTypeInfo()
      Specified by:
      getSchemaTypeInfo in interface Attr

    • getNodeValue

      public String getNodeValue()
      Returns the node value.
      Specified by:
      getNodeValue in interface Node
      Overrides:
      getNodeValue in class NodeImpl

    • getName

      public String getName()
      In Attributes, NodeName is considered a synonym for the attribute's Name
      Specified by:
      getName in interface Attr

    • setValue

      public void setValue(String newvalue)
      The DOM doesn't clearly define what setValue(null) means. I've taken it as "remove all children", which from outside should appear similar to setting it to the empty string.
      Specified by:
      setValue in interface Attr

    • getValue

      public String getValue()
      The "string value" of an Attribute is its text representation, which in turn is a concatenation of the string values of its children.
      Specified by:
      getValue in interface Attr

    • getSpecified

      public boolean getSpecified()
      The "specified" flag is true if and only if this attribute's value was explicitly specified in the original document. Note that the implementation, not the user, is in charge of this property. If the user asserts an Attribute value (even if it ends up having the same value as the default), it is considered a specified attribute. If you really want to revert to the default, delete the attribute from the Element, and the Implementation will re-assert the default (if any) in its place, with the appropriate specified=false setting.
      Specified by:
      getSpecified in interface Attr

    • getOwnerElement

      public Element getOwnerElement()
      Returns the element node that this attribute is associated with, or null if the attribute has not been added to an element.
      Specified by:
      getOwnerElement in interface Attr

    • setSpecified

      public void setSpecified(boolean arg)

    • setType

      public void setType(String type)

    • toString

      public String toString()
      Overrides:
      toString in class NodeImpl

    • hasChildNodes

      public boolean hasChildNodes()
      Test whether this node has any children. Convenience shorthand for (Node.getFirstChild()!=null)

      By default we do not have any children, ParentNode overrides this. Test whether this node has any children. Convenience shorthand for (Node.getFirstChild()!=null)

      Specified by:
      hasChildNodes in interface Node
      Overrides:
      hasChildNodes in class NodeImpl
      See Also:

    • getChildNodes

      public NodeList getChildNodes()
      Obtain a NodeList enumerating all children of this node. If there are none, an (initially) empty NodeList is returned.

      NodeLists are "live"; as children are added/removed the NodeList will immediately reflect those changes. Also, the NodeList refers to the actual nodes, so changes to those nodes made via the DOM tree will be reflected in the NodeList and vice versa.

      In this implementation, Nodes implement the NodeList interface and provide their own getChildNodes() support. Other DOMs may solve this differently. Obtain a NodeList enumerating all children of this node. If there are none, an (initially) empty NodeList is returned.

      NodeLists are "live"; as children are added/removed the NodeList will immediately reflect those changes. Also, the NodeList refers to the actual nodes, so changes to those nodes made via the DOM tree will be reflected in the NodeList and vice versa.

      In this implementation, Nodes implement the NodeList interface and provide their own getChildNodes() support. Other DOMs may solve this differently.

      Specified by:
      getChildNodes in interface Node
      Overrides:
      getChildNodes in class NodeImpl

    • getFirstChild

      public Node getFirstChild()
      The first child of this Node, or null if none.

      By default we do not have any children, ParentNode overrides this.

      Specified by:
      getFirstChild in interface Node
      Overrides:
      getFirstChild in class NodeImpl
      See Also:

    • getLastChild

      public Node getLastChild()
      The first child of this Node, or null if none.

      By default we do not have any children, ParentNode overrides this.

      Specified by:
      getLastChild in interface Node
      Overrides:
      getLastChild in class NodeImpl
      See Also:

    • lastChild

      final ChildNode lastChild()

    • insertBefore

      public Node insertBefore(Node newChild, Node refChild) throws DOMException
      Move one or more node(s) to our list of children. Note that this implicitly removes them from their previous parent.

      By default we do not accept any children, ParentNode overrides this. Move one or more node(s) to our list of children. Note that this implicitly removes them from their previous parent.

      Specified by:
      insertBefore in interface Node
      Overrides:
      insertBefore in class NodeImpl
      Parameters:
      newChild - The Node to be moved to our subtree. As a convenience feature, inserting a DocumentNode will instead insert all its children.
      refChild - Current child which newChild should be placed immediately before. If refChild is null, the insertion occurs after all existing Nodes, like appendChild().
      Returns:
      newChild, in its new state (relocated, or emptied in the case of DocumentNode.)
      Throws:
      DOMException - HIERARCHY_REQUEST_ERR if newChild is of a type that shouldn't be a child of this node, or if newChild is an ancestor of this node.
      DOMException - WRONG_DOCUMENT_ERR if newChild has a different owner document than we do.
      DOMException - NOT_FOUND_ERR if refChild is not a child of this node.
      DOMException - NO_MODIFICATION_ALLOWED_ERR if this node is read-only.
      See Also:

    • internalInsertBefore

      Node internalInsertBefore(Node newChild, Node refChild, boolean replace) throws DOMException
      Throws:
      DOMException

    • removeChild

      public Node removeChild(Node oldChild) throws DOMException
      Remove a child from this Node. The removed child's subtree remains intact so it may be re-inserted elsewhere.
      Specified by:
      removeChild in interface Node
      Overrides:
      removeChild in class NodeImpl
      Returns:
      oldChild, in its new state (removed).
      Throws:
      DOMException - NOT_FOUND_ERR if oldChild is not a child of this node.
      DOMException - NO_MODIFICATION_ALLOWED_ERR if this node is read-only.
      See Also:

    • internalRemoveChild

      Node internalRemoveChild(Node oldChild, boolean replace) throws DOMException
      NON-DOM INTERNAL: Within DOM actions,we sometimes need to be able to control which mutation events are spawned. This version of the removeChild operation allows us to do so. It is not intended for use by application programs.
      Throws:
      DOMException

    • replaceChild

      public Node replaceChild(Node newChild, Node oldChild) throws DOMException
      Make newChild occupy the location that oldChild used to have. Note that newChild will first be removed from its previous parent, if any. Equivalent to inserting newChild before oldChild, then removing oldChild.
      Specified by:
      replaceChild in interface Node
      Overrides:
      replaceChild in class NodeImpl
      Returns:
      oldChild, in its new state (removed).
      Throws:
      DOMException - HIERARCHY_REQUEST_ERR if newChild is of a type that shouldn't be a child of this node, or if newChild is one of our ancestors.
      DOMException - WRONG_DOCUMENT_ERR if newChild has a different owner document than we do.
      DOMException - NOT_FOUND_ERR if oldChild is not a child of this node.
      DOMException - NO_MODIFICATION_ALLOWED_ERR if this node is read-only.
      See Also:

    • getLength

      public int getLength()
      NodeList method: Count the immediate children of this node
      Specified by:
      getLength in interface NodeList
      Overrides:
      getLength in class NodeImpl
      Returns:
      int

    • item

      public Node item(int index)
      NodeList method: Return the Nth immediate child of this node, or null if the index is out of bounds.
      Specified by:
      item in interface NodeList
      Overrides:
      item in class NodeImpl
      Parameters:
      index - int
      Returns:
      org.w3c.dom.Node

    • isEqualNode

      public boolean isEqualNode(Node arg)
      DOM Level 3 WD- Experimental. Override inherited behavior from ParentNode to support deep equal. isEqualNode is always deep on Attr nodes.
      Specified by:
      isEqualNode in interface Node
      Overrides:
      isEqualNode in class NodeImpl
      Parameters:
      arg - The node to compare equality with.
      Returns:
      If the nodes, and possibly subtrees are equal, true otherwise false.

    • isDerivedFrom

      public boolean isDerivedFrom(String typeNamespaceArg, String typeNameArg, int derivationMethod)
      Introduced in DOM Level 3.

      Checks if a type is derived from another by restriction. See: http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo-isDerivedFrom

      Specified by:
      isDerivedFrom in interface TypeInfo
      Parameters:
      typeNamespaceArg - The namspace of the ancestor type declaration
      typeNameArg - The name of the ancestor type declaration
      derivationMethod - The derivation method
      Returns:
      boolean True if the type is derived by restriciton for the reference type

    • checkNormalizationAfterInsert

      void checkNormalizationAfterInsert(ChildNode insertedChild)
      Checks the normalized state of this node after inserting a child. If the inserted child causes this node to be unnormalized, then this node is flagged accordingly. The conditions for changing the normalized state are:
      • The inserted child is a text node and one of its adjacent siblings is also a text node.
      • The inserted child is is itself unnormalized.
      Parameters:
      insertedChild - the child node that was inserted into this node
      Throws:
      NullPointerException - if the inserted child is null

    • checkNormalizationAfterRemove

      void checkNormalizationAfterRemove(ChildNode previousSibling)
      Checks the normalized of this node after removing a child. If the removed child causes this node to be unnormalized, then this node is flagged accordingly. The conditions for changing the normalized state are:
      • The removed child had two adjacent siblings that were text nodes.
      Parameters:
      previousSibling - the previous sibling of the removed child, or null