Package org.htmlunit.cyberneko.xerces.dom

Class EntityReferenceImpl

  • All Implemented Interfaces:
    Cloneable, EntityReference, EventTarget, Node, NodeList
    public class EntityReferenceImpl
extends ParentNode
implements EntityReference
    EntityReference models the XML &entityname; syntax, when used for entities defined by the DOM. Entities hardcoded into XML, such as character entities, should instead have been translated into text by the code which generated the DOM tree.

    An XML processor has the alternative of fully expanding Entities into the normal document tree. If it does so, no EntityReference nodes will appear.

    Similarly, non-validating XML processors are not required to read or process entity declarations made in the external subset or declared in external parameter entities. Hence, some applications may not make the replacement value available for Parsed Entities of these types.

    EntityReference behaves as a read-only node, and the children of the EntityReference (which reflect those of the Entity, and should also be read-only) give its replacement value, if any. They are supposed to automagically stay in synch if the DocumentType is updated with new values for the Entity.

    The defined behavior makes efficient storage difficult for the DOM implementor. We can't just look aside to the Entity's definition in the DocumentType since those nodes have the wrong parent (unless we can come up with a clever "imaginary parent" mechanism). We must at least appear to clone those children... which raises the issue of keeping the reference synchronized with its parent. This leads me back to the "cached image of centrally defined data" solution, much as I dislike it.

    For now I have decided, since REC-DOM-Level-1-19980818 doesn't cover this in much detail, that synchronization doesn't have to be considered while the user is deep in the tree. That is, if you're looking within one of the EntityReferennce's children and the Entity changes, you won't be informed; instead, you will continue to access the same object -- which may or may not still be part of the tree. This is the same behavior that obtains elsewhere in the DOM if the subtree you're looking at is deleted from its parent, so it's acceptable here. (If it really bothers folks, we could set things up so deleted subtrees are walked and marked invalid, but that's not part of the DOM's defined behavior.)

    As a result, only the EntityReference itself has to be aware of changes in the Entity. And it can take advantage of the same structure-change-monitoring code I implemented to support DeepNodeList.

    Author:
    Arnaud Le Hors, IBM, Joe Kesselman, IBM, Andy Clark, IBM, Ralf Pfeiffer, IBM

    • Field Detail

      • name

        protected final String name
        Name of Entity referenced

    • Method Detail

      • 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. 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. Returns the name of the entity referenced
        Specified by:
        getNodeName in interface Node
        Specified by:
        getNodeName in class NodeImpl

      • getBaseURI

        public String getBaseURI()
        The absolute base URI of this node or null if undefined. This value is computed according to . However, when the Document supports the feature "HTML" , the base URI is computed using first the value of the href attribute of the HTML BASE element if any, and the value of the documentURI attribute from the Document interface otherwise.
        When the node is an Element, a Document or a a ProcessingInstruction, this attribute represents the properties [base URI] defined in . When the node is a Notation, an Entity, or an EntityReference, this attribute represents the properties [declaration base URI] in the . How will this be affected by resolution of relative namespace URIs issue?It's not.Should this only be on Document, Element, ProcessingInstruction, Entity, and Notation nodes, according to the infoset? If not, what is it equal to on other nodes? Null? An empty string? I think it should be the parent's.No.Should this be read-only and computed or and actual read-write attribute?Read-only and computed (F2F 19 Jun 2000 and teleconference 30 May 2001).If the base HTML element is not yet attached to a document, does the insert change the Document.baseURI? Yes. (F2F 26 Sep 2001) Returns the absolute base URI of this node or null if the implementation wasn't able to obtain an absolute URI. Note: If the URI is malformed, a null is returned.
        Specified by:
        getBaseURI in interface Node
        Overrides:
        getBaseURI in class NodeImpl
        Returns:
        The absolute base URI of this node or null.

      • getEntityRefValue

        protected String getEntityRefValue()
        NON-DOM: compute string representation of the entity reference. This method is used to retrieve a string value for an attribute node that has child nodes.
        Returns:
        String representing a value of this entity ref. or null if any node other than EntityReference, Text is encountered during computation

      • synchronizeChildren

        protected void synchronizeChildren()
        Override this method in subclass to hook in efficient internal data structure. EntityReference's children are a reflection of those defined in the named Entity. This method creates them if they haven't been created yet. This doesn't support editing the Entity though, since this only called once for all.
        Overrides:
        synchronizeChildren in class ParentNode