NAME¶
XML::DOM::DocumentFragment - Facilitates cut & paste in XML::DOM documents
DESCRIPTION¶
XML::DOM::DocumentFragment extends XML::DOM::Node
DocumentFragment is a "lightweight" or "minimal" Document
object. It is very common to want to be able to extract a portion of a
document's tree or to create a new fragment of a document. Imagine
implementing a user command like cut or rearranging a document by moving
fragments around. It is desirable to have an object which can hold such
fragments and it is quite natural to use a Node for this purpose. While it is
true that a Document object could fulfil this role, a Document object can
potentially be a heavyweight object, depending on the underlying
implementation. What is really needed for this is a very lightweight object.
DocumentFragment is such an object.
Furthermore, various operations -- such as inserting nodes as children of
another Node -- may take DocumentFragment objects as arguments; this results
in all the child nodes of the DocumentFragment being moved to the child list
of this node.
The children of a DocumentFragment node are zero or more nodes representing the
tops of any sub-trees defining the structure of the document. DocumentFragment
nodes do not need to be well-formed XML documents (although they do need to
follow the rules imposed upon well-formed XML parsed entities, which can have
multiple top nodes). For example, a DocumentFragment might have only one child
and that child node could be a Text node. Such a structure model represents
neither an HTML document nor a well-formed XML document.
When a DocumentFragment is inserted into a Document (or indeed any other Node
that may take children) the children of the DocumentFragment and not the
DocumentFragment itself are inserted into the Node. This makes the
DocumentFragment very useful when the user wishes to create nodes that are
siblings; the DocumentFragment acts as the parent of these nodes so that the
user can use the standard methods from the Node interface, such as
insertBefore() and
appendChild().