ParserConfigurationSettings


1   /*
2    * Copyright 2001, 2002,2004 The Apache Software Foundation.
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.xerces.util;
18  
19  import java.util.ArrayList  ;
20  import java.util.HashMap  ;
21  
22  import org.apache.xerces.impl.Constants;
23  import org.apache.xerces.xni.parser.XMLComponentManager;
24  import org.apache.xerces.xni.parser.XMLConfigurationException;
25  
26  /**
27   * This class implements the basic operations for managing parser
28   * configuration features and properties. This utility class can
29   * be used as a base class for parser configurations or separately
30   * to encapsulate a number of parser settings as a component
31   * manager.
32   * <p>
33   * This class can be constructed with a "parent" settings object
34   * (in the form of an <code>XMLComponentManager</code>) that allows
35   * parser configuration settings to be "chained" together.
36   *
37   * @author Andy Clark, IBM
38   *
39   * @version $Id: ParserConfigurationSettings.java,v 1.11 2004/04/25 05:05:50 mrglavas Exp $
40   */
41  public class ParserConfigurationSettings
42      implements XMLComponentManager {
43          
44      protected static final String   PARSER_SETTINGS = 
45              Constants.XERCES_FEATURE_PREFIX + Constants.PARSER_SETTINGS;    
46  
47      //
48      // Data
49      //
50  
51      // data
52  
53      /** Recognized properties. */
54      protected ArrayList   fRecognizedProperties;
55  
56      /** Properties. */
57      protected HashMap   fProperties;
58  
59      /** Recognized features. */
60      protected ArrayList   fRecognizedFeatures;
61  
62      /** Features. */
63      protected HashMap   fFeatures;
64  
65      /** Parent parser configuration settings. */
66      protected XMLComponentManager fParentSettings;
67  
68      //
69      // Constructors
70      //
71  
72      /** Default Constructor. */
73      public ParserConfigurationSettings() {
74          this(null);
75      } // <init>()
76  
77      /**
78       * Constructs a parser configuration settings object with a
79       * parent settings object.
80       */
81      public ParserConfigurationSettings(XMLComponentManager parent) {
82  
83          // create storage for recognized features and properties
84          fRecognizedFeatures = new ArrayList  ();
85          fRecognizedProperties = new ArrayList  ();
86  
87          // create table for features and properties
88          fFeatures = new HashMap  ();
89          fProperties = new HashMap  ();
90  
91          // save parent
92          fParentSettings = parent;
93  
94      } // <init>(XMLComponentManager)
95  
96      //
97      // XMLParserConfiguration methods
98      //
99  
100     /**
101      * Allows a parser to add parser specific features to be recognized
102      * and managed by the parser configuration.
103      *
104      * @param featureIds An array of the additional feature identifiers 
105      *                   to be recognized.
106      */
107     public void addRecognizedFeatures(String  [] featureIds) {
108 
109         // add recognized features
110         int featureIdsCount = featureIds != null ? featureIds.length : 0;
111         for (int i = 0; i < featureIdsCount; i++) {
112             String   featureId = featureIds[i];
113             if (!fRecognizedFeatures.contains(featureId)) {
114                 fRecognizedFeatures.add(featureId);
115             }
116         }
117 
118     } // addRecognizedFeatures(String[])
119 
120     /**
121      * Set the state of a feature.
122      *
123      * Set the state of any feature in a SAX2 parser.  The parser
124      * might not recognize the feature, and if it does recognize
125      * it, it might not be able to fulfill the request.
126      *
127      * @param featureId The unique identifier (URI) of the feature.
128      * @param state The requested state of the feature (true or false).
129      *
130      * @exception org.apache.xerces.xni.parser.XMLConfigurationException If the
131      *            requested feature is not known.
132      */
133     public void setFeature(String   featureId, boolean state)
134         throws XMLConfigurationException {
135 
136         // check and store
137         checkFeature(featureId);
138 
139         fFeatures.put(featureId, state ? Boolean.TRUE : Boolean.FALSE);
140     } // setFeature(String,boolean)
141 
142     /**
143      * Allows a parser to add parser specific properties to be recognized
144      * and managed by the parser configuration.
145      *
146      * @param propertyIds An array of the additional property identifiers 
147      *                    to be recognized.
148      */
149     public void addRecognizedProperties(String  [] propertyIds) {
150 
151         // add recognizedProperties
152         int propertyIdsCount = propertyIds != null ? propertyIds.length : 0;
153         for (int i = 0; i < propertyIdsCount; i++) {
154             String   propertyId = propertyIds[i];
155             if (!fRecognizedProperties.contains(propertyId)) {
156                 fRecognizedProperties.add(propertyId);
157             }
158         }
159 
160     } // addRecognizedProperties(String[])
161 
162     /**
163      * setProperty
164      * 
165      * @param propertyId 
166      * @param value 
167      * @exception org.apache.xerces.xni.parser.XMLConfigurationException If the
168      *            requested feature is not known.
169      */
170     public void setProperty(String   propertyId, Object   value)
171         throws XMLConfigurationException {
172 
173         // check and store
174         checkProperty(propertyId);
175         fProperties.put(propertyId, value);
176 
177     } // setProperty(String,Object)
178 
179     //
180     // XMLComponentManager methods
181     //
182 
183     /**
184      * Returns the state of a feature.
185      * 
186      * @param featureId The feature identifier.
187          * @return true if the feature is supported
188      * 
189      * @throws XMLConfigurationException Thrown for configuration error.
190      *                                   In general, components should
191      *                                   only throw this exception if
192      *                                   it is <strong>really</strong>
193      *                                   a critical error.
194      */
195     public boolean getFeature(String   featureId)
196         throws XMLConfigurationException {
197 
198         Boolean   state = (Boolean  ) fFeatures.get(featureId);
199 
200         if (state == null) {
201             checkFeature(featureId);
202             return false;
203         }
204         return state.booleanValue();
205 
206     } // getFeature(String):boolean
207 
208     /**
209      * Returns the value of a property.
210      * 
211      * @param propertyId The property identifier.
212          * @return the value of the property
213      * 
214      * @throws XMLConfigurationException Thrown for configuration error.
215      *                                   In general, components should
216      *                                   only throw this exception if
217      *                                   it is <strong>really</strong>
218      *                                   a critical error.
219      */
220     public Object   getProperty(String   propertyId)
221         throws XMLConfigurationException {
222 
223         Object   propertyValue = fProperties.get(propertyId);
224 
225         if (propertyValue == null) {
226             checkProperty(propertyId);
227         }
228 
229         return propertyValue;
230 
231     } // getProperty(String):Object
232 
233     //
234     // Protected methods
235     //
236 
237     /**
238      * Check a feature. If feature is known and supported, this method simply
239      * returns. Otherwise, the appropriate exception is thrown.
240      *
241      * @param featureId The unique identifier (URI) of the feature.
242      *
243      * @exception org.apache.xerces.xni.parser.XMLConfigurationException If the
244      *            requested feature is not known.
245      */
246     protected void checkFeature(String   featureId)
247         throws XMLConfigurationException {
248 
249         // check feature
250         if (!fRecognizedFeatures.contains(featureId)) {
251             if (fParentSettings != null) {
252                 fParentSettings.getFeature(featureId);
253             }
254             else {
255                 short type = XMLConfigurationException.NOT_RECOGNIZED;
256                 throw new XMLConfigurationException(type, featureId);
257             }
258         }
259 
260     } // checkFeature(String)
261 
262     /**
263      * Check a property. If the property is known and supported, this method
264      * simply returns. Otherwise, the appropriate exception is thrown.
265      *
266      * @param propertyId The unique identifier (URI) of the property
267      *                   being set.
268      * @exception org.apache.xerces.xni.parser.XMLConfigurationException If the
269      *            requested feature is not known.
270      */
271     protected void checkProperty(String   propertyId)
272         throws XMLConfigurationException {
273 
274         // check property
275         if (!fRecognizedProperties.contains(propertyId)) {
276             if (fParentSettings != null) {
277                 fParentSettings.getProperty(propertyId);
278             }
279             else {
280                 short type = XMLConfigurationException.NOT_RECOGNIZED;
281                 throw new XMLConfigurationException(type, propertyId);
282             }
283         }
284 
285     } // checkProperty(String)
286 
287 } // class ParserConfigurationSettings
288
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