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Java > Open Source Codes > com > sun > org > apache > xerces > internal > dom > DOMImplementationSourceImpl


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57
58 package com.sun.org.apache.xerces.internal.dom;
59
60 import java.util.StringTokenizer JavaDoc;
61 import java.util.Vector JavaDoc;
62 import org.w3c.dom.DOMImplementationList JavaDoc;
63 import org.w3c.dom.DOMImplementationSource JavaDoc;
64 import org.w3c.dom.DOMImplementation JavaDoc;
65 import com.sun.org.apache.xerces.internal.dom.DOMImplementationListImpl;
66
67 /**
68  * Supply one the right implementation, based upon requested features. Each
69  * implemented <code>DOMImplementationSource</code> object is listed in the
70  * binding-specific list of available sources so that its
71  * <code>DOMImplementation</code> objects are made available.
72  *
73  * <p>See also the <a HREF='http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/core.html#DOMImplementationSource'>Document Object Model (DOM) Level 3 Core Specification</a>.
74  *
75  * @version $Id: DOMImplementationSourceImpl.java,v 1.15 2004/04/23 21:45:04 mrglavas Exp $
76  */
77 public class DOMImplementationSourceImpl
78     implements DOMImplementationSource JavaDoc {
79
80     /**
81      * A method to request a DOM implementation.
82      * @param features A string that specifies which features are required.
83      * This is a space separated list in which each feature is specified
84      * by its name optionally followed by a space and a version number.
85      * This is something like: "XML 1.0 Traversal Events 2.0"
86      * @return An implementation that has the desired features, or
87      * <code>null</code> if this source has none.
88      */
89     public DOMImplementation JavaDoc getDOMImplementation(String JavaDoc features) {
90         // first check whether the CoreDOMImplementation would do
91 DOMImplementation JavaDoc impl =
92             CoreDOMImplementationImpl.getDOMImplementation();
93         if (testImpl(impl, features)) {
94             return impl;
95         }
96         // if not try the DOMImplementation
97 impl = DOMImplementationImpl.getDOMImplementation();
98         if (testImpl(impl, features)) {
99             return impl;
100         }
101         
102         return null;
103     }
104     
105     /**
106      * A method to request a list of DOM implementations that support the
107      * specified features and versions, as specified in .
108      * @param features A string that specifies which features and versions
109      * are required. This is a space separated list in which each feature
110      * is specified by its name optionally followed by a space and a
111      * version number. This is something like: "XML 3.0 Traversal +Events
112      * 2.0"
113      * @return A list of DOM implementations that support the desired
114      * features.
115      */
116     public DOMImplementationList JavaDoc getDOMImplementationList(String JavaDoc features) {
117         // first check whether the CoreDOMImplementation would do
118 DOMImplementation JavaDoc impl = CoreDOMImplementationImpl.getDOMImplementation();
119         final Vector JavaDoc implementations = new Vector JavaDoc();
120         if (testImpl(impl, features)) {
121             implementations.addElement(impl);
122         }
123         impl = DOMImplementationImpl.getDOMImplementation();
124         if (testImpl(impl, features)) {
125             implementations.addElement(impl);
126         }
127
128         return new DOMImplementationListImpl(implementations);
129     }
130
131     boolean testImpl(DOMImplementation JavaDoc impl, String JavaDoc features) {
132        
133         StringTokenizer JavaDoc st = new StringTokenizer JavaDoc(features);
134         String JavaDoc feature = null;
135         String JavaDoc version = null;
136  
137         if (st.hasMoreTokens()) {
138            feature = st.nextToken();
139         }
140         while (feature != null) {
141            boolean isVersion = false;
142            if (st.hasMoreTokens()) {
143                char c;
144                version = st.nextToken();
145                c = version.charAt(0);
146                switch (c) {
147                case '0': case '1': case '2': case '3': case '4':
148                case '5': case '6': case '7': case '8': case '9':
149                    isVersion = true;
150                }
151            } else {
152                version = null;
153            }
154            if (isVersion) {
155                if (!impl.hasFeature(feature, version)) {
156                    return false;
157                }
158                if (st.hasMoreTokens()) {
159                    feature = st.nextToken();
160                } else {
161                    feature = null;
162                }
163            } else {
164                if (!impl.hasFeature(feature, null)) {
165                    return false;
166                }
167                feature = version;
168            }
169         }
170         return true;
171     }
172 }
173
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