org.htmlunit.cyberneko.xerces.dom.EntityReferenceImpl Maven / Gradle / Ivy
/*
* Copyright (c) 2017-2024 Ronald Brill
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.htmlunit.cyberneko.xerces.dom;
import org.w3c.dom.DocumentType;
import org.w3c.dom.EntityReference;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
/**
* 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
* @author Joe Kesselman, IBM
* @author Andy Clark, IBM
* @author Ralf Pfeiffer, IBM
*/
public class EntityReferenceImpl extends ParentNode implements EntityReference {
/** Name of Entity referenced */
protected final String name;
// Factory constructor.
public EntityReferenceImpl(final CoreDocumentImpl ownerDoc, final String name) {
super(ownerDoc);
this.name = name;
needsSyncChildren(true);
}
/**
* {@inheritDoc}
*
* 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.
*/
@Override
public short getNodeType() {
return Node.ENTITY_REFERENCE_NODE;
}
/**
* {@inheritDoc}
*
* Returns the name of the entity referenced
*/
@Override
public String getNodeName() {
return name;
}
/**
* {@inheritDoc}
*
* Clone node.
*/
@Override
public Node cloneNode(final boolean deep) {
return super.cloneNode(deep);
}
/**
* {@inheritDoc}
*
* 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.
*
* @return The absolute base URI of this node or null.
*/
@Override
public String getBaseURI() {
final DocumentType doctype;
final NamedNodeMap entities;
final EntityImpl entDef;
if (null != (doctype = getOwnerDocument().getDoctype()) && null != (entities = doctype.getEntities())) {
entDef = (EntityImpl) entities.getNamedItem(getNodeName());
if (entDef != null) {
return entDef.getBaseURI();
}
}
return null;
}
/**
* 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.
*
* @return String representing a value of this entity ref. or null if any node
* other than EntityReference, Text is encountered during computation
*/
protected String getEntityRefValue() {
if (needsSyncChildren()) {
synchronizeChildren();
}
String value;
if (firstChild != null) {
if (firstChild.getNodeType() == Node.ENTITY_REFERENCE_NODE) {
value = ((EntityReferenceImpl) firstChild).getEntityRefValue();
}
else if (firstChild.getNodeType() == Node.TEXT_NODE) {
value = firstChild.getNodeValue();
}
else {
// invalid to have other types of nodes in attr value
return null;
}
if (firstChild.nextSibling_ == null) {
return value;
}
final StringBuilder buff = new StringBuilder(value);
ChildNode next = firstChild.nextSibling_;
while (next != null) {
if (next.getNodeType() == Node.ENTITY_REFERENCE_NODE) {
value = ((EntityReferenceImpl) next).getEntityRefValue();
}
else if (next.getNodeType() == Node.TEXT_NODE) {
value = next.getNodeValue();
}
else {
// invalid to have other types of nodes in attr value
return null;
}
buff.append(value);
next = next.nextSibling_;
}
return buff.toString();
}
return "";
}
/**
* {@inheritDoc}
*
* 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.
*/
@Override
protected void synchronizeChildren() {
// no need to synchronize again
needsSyncChildren(false);
final DocumentType doctype;
final NamedNodeMap entities;
final EntityImpl entDef;
if (null != (doctype = getOwnerDocument().getDoctype()) && null != (entities = doctype.getEntities())) {
entDef = (EntityImpl) entities.getNamedItem(getNodeName());
// No Entity by this name, stop here.
if (entDef == null) {
return;
}
// If entity's definition exists, clone its kids
for (Node defkid = entDef.getFirstChild(); defkid != null; defkid = defkid.getNextSibling()) {
final Node newkid = defkid.cloneNode(true);
insertBefore(newkid, null);
}
}
}
}