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      1 /*
      2  * Copyright (C) 2007 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package org.apache.harmony.xml.dom;
     18 
     19 import org.w3c.dom.DOMException;
     20 import org.w3c.dom.DOMImplementation;
     21 import org.w3c.dom.Document;
     22 import org.w3c.dom.DocumentType;
     23 
     24 /**
     25  * Provides a straightforward implementation of the corresponding W3C DOM
     26  * interface. The class is used internally only, thus only notable members that
     27  * are not in the original interface are documented (the W3C docs are quite
     28  * extensive). Hope that's ok.
     29  * <p>
     30  * Some of the fields may have package visibility, so other classes belonging to
     31  * the DOM implementation can easily access them while maintaining the DOM tree
     32  * structure.
     33  */
     34 public final class DOMImplementationImpl implements DOMImplementation {
     35 
     36     // Singleton instance.
     37     private static DOMImplementationImpl instance;
     38 
     39     DOMImplementationImpl() {
     40     }
     41 
     42     public Document createDocument(String namespaceURI, String qualifiedName,
     43             DocumentType doctype) throws DOMException {
     44         return new DocumentImpl(this, namespaceURI, qualifiedName, doctype, null);
     45     }
     46 
     47     public DocumentType createDocumentType(String qualifiedName,
     48             String publicId, String systemId) throws DOMException {
     49         return new DocumentTypeImpl(null, qualifiedName, publicId, systemId);
     50     }
     51 
     52     public boolean hasFeature(String feature, String version) {
     53         boolean anyVersion = version == null || version.length() == 0;
     54         if (feature.startsWith("+")) {
     55             feature = feature.substring(1);
     56         }
     57 
     58         // TODO: fully implement these APIs:
     59         // "LS" (org.w3c.dom.ls) versions "3.0"
     60         // "ElementTraversal" (org.w3c.dom.traversal) versions "1.0"
     61 
     62         if (feature.equalsIgnoreCase("Core")) {
     63             return anyVersion || version.equals("1.0") || version.equals("2.0") || version.equals("3.0");
     64         } else if (feature.equalsIgnoreCase("XML")) {
     65             return anyVersion || version.equals("1.0") || version.equals("2.0") || version.equals("3.0");
     66         } else if (feature.equalsIgnoreCase("XMLVersion")) {
     67             return anyVersion || version.equals("1.0") || version.equals("1.1");
     68         } else {
     69             return false;
     70         }
     71     }
     72 
     73     /**
     74      * Requests the singleton instance of the class. Creates it first, if
     75      * necessary.
     76      *
     77      * @return The singleton Android DOMImplementationImpl instance.
     78      */
     79     public static DOMImplementationImpl getInstance() {
     80         if (instance == null) {
     81             instance = new DOMImplementationImpl();
     82         }
     83 
     84         return instance;
     85     }
     86 
     87     public Object getFeature(String feature, String version) {
     88         return hasFeature(feature, version) ? this : null;
     89     }
     90 }
     91