All Downloads are FREE. Search and download functionalities are using the official Maven repository.

org.apache.xerces.dom.DeferredEntityReferenceImpl Maven / Gradle / Ivy

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 * 
 *      http://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.apache.xerces.dom;

/**
 * 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 * * @version $Id: DeferredEntityReferenceImpl.java 447266 2006-09-18 05:57:49Z mrglavas $ * @since PR-DOM-Level-1-19980818. */ public class DeferredEntityReferenceImpl extends EntityReferenceImpl implements DeferredNode { // // Constants // /** Serialization version. */ static final long serialVersionUID = 390319091370032223L; // // Data // /** Node index. */ protected transient int fNodeIndex; // // Constructors // /** * This is the deferred constructor. Only the fNodeIndex is given here. * All other data, can be requested from the ownerDocument via the index. */ DeferredEntityReferenceImpl(DeferredDocumentImpl ownerDocument, int nodeIndex) { super(ownerDocument, null); fNodeIndex = nodeIndex; needsSyncData(true); } // (DeferredDocumentImpl,int) // // DeferredNode methods // /** Returns the node index. */ public int getNodeIndex() { return fNodeIndex; } // // Protected methods // /** * Synchronize the entity data. This is special because of the way * that the "fast" version stores the information. */ protected void synchronizeData() { // no need to sychronize again needsSyncData(false); // get the node data DeferredDocumentImpl ownerDocument = (DeferredDocumentImpl)this.ownerDocument; name = ownerDocument.getNodeName(fNodeIndex); baseURI = ownerDocument.getNodeValue(fNodeIndex); } // synchronizeData() /** Synchronize the children. */ protected void synchronizeChildren() { // no need to synchronize again needsSyncChildren(false); // get children isReadOnly(false); DeferredDocumentImpl ownerDocument = (DeferredDocumentImpl) ownerDocument(); ownerDocument.synchronizeChildren(this, fNodeIndex); setReadOnly(true, true); } // synchronizeChildren() } // class DeferredEntityReferenceImpl





© 2015 - 2024 Weber Informatics LLC | Privacy Policy