public class

EntityReferenceImpl

extends ParentNode
implements EntityReference
java.lang.Object
   ↳ org.apache.xerces.dom.NodeImpl
     ↳ org.apache.xerces.dom.ChildNode
       ↳ org.apache.xerces.dom.ParentNode
         ↳ org.apache.xerces.dom.EntityReferenceImpl
Known Direct Subclasses

Class Overview

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.@xerces.internal

Summary

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Inherited Constants
From class org.apache.xerces.dom.NodeImpl
From interface org.w3c.dom.Node
Fields
protected String baseURI Base URI
protected String name Name of Entity referenced
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Inherited Fields
From class org.apache.xerces.dom.ParentNode
From class org.apache.xerces.dom.ChildNode
From class org.apache.xerces.dom.NodeImpl
Public Constructors
EntityReferenceImpl(CoreDocumentImpl ownerDoc, String name)
Factory constructor.
Public Methods
Node cloneNode(boolean deep)
Clone node.
String getBaseURI()
Returns the absolute base URI of this node or null if the implementation wasn't able to obtain an absolute URI.
String getNodeName()
Returns the name of the entity referenced
short getNodeType()
A short integer indicating what type of node this is.
void setBaseURI(String uri)
NON-DOM: set base uri
void setReadOnly(boolean readOnly, boolean deep)
NON-DOM: sets the node and its children value.
Protected Methods
String getEntityRefValue()
NON-DOM: compute string representation of the entity reference.
void synchronizeChildren()
EntityReference's children are a reflection of those defined in the named Entity.
[Expand]
Inherited Methods
From class org.apache.xerces.dom.ParentNode
From class org.apache.xerces.dom.ChildNode
From class org.apache.xerces.dom.NodeImpl
From class java.lang.Object
From interface org.w3c.dom.Node
From interface org.w3c.dom.NodeList
From interface org.w3c.dom.events.EventTarget

Fields

protected String baseURI

Base URI

protected String name

Name of Entity referenced

Public Constructors

public EntityReferenceImpl (CoreDocumentImpl ownerDoc, String name)

Factory constructor.

Public Methods

public Node cloneNode (boolean deep)

Clone node.

public String getBaseURI ()

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.

Returns
  • The absolute base URI of this node or null.

public String getNodeName ()

Returns the name of the entity referenced

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.

public void setBaseURI (String uri)

NON-DOM: set base uri

public void setReadOnly (boolean readOnly, boolean deep)

NON-DOM: sets the node and its children value.

Note: make sure that entity reference and its kids could be set readonly.

Parameters
readOnly True or false as desired.
deep If true, children are also toggled. Note that this will not change the state of an EntityReference or its children, which are always read-only.

Protected Methods

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

protected void synchronizeChildren ()

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.