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1   /*
2    * Copyright 2004 Sun Microsystems, Inc.
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 com.sun.syndication.io.impl;
18  
19  import com.sun.syndication.feed.WireFeed;
20  import com.sun.syndication.feed.rss.*;
21  import com.sun.syndication.io.FeedException;
22  import org.jdom.Document;
23  import org.jdom.Element;
24  import org.jdom.Namespace;
25  
26  import java.util.List;
27  
28  
29  /***
30   * Feed Generator for RSS 0.90
31   * <p/>
32   *
33   * @author Elaine Chien
34   */
35  public class RSS090Generator extends BaseWireFeedGenerator {
36  
37      private static final String RDF_URI = "http://www.w3.org/1999/02/22-rdf-syntax-ns#";
38      private static final String RSS_URI = "http://my.netscape.com/rdf/simple/0.9/";
39      private static final String CONTENT_URI = "http://purl.org/rss/1.0/modules/content/";
40  
41      private static final Namespace RDF_NS = Namespace.getNamespace("rdf", RDF_URI);
42      private static final Namespace RSS_NS = Namespace.getNamespace(RSS_URI);
43      private static final Namespace CONTENT_NS = Namespace.getNamespace("content", CONTENT_URI);
44  
45      public RSS090Generator() {
46          this("rss_0.9");
47      }
48  
49      protected RSS090Generator(String type) {
50          super(type);
51      }
52  
53      public Document generate(WireFeed feed) throws FeedException {
54          Channel channel = (Channel)feed;
55          Element root = createRootElement(channel);
56          populateFeed(channel,root);
57          purgeUnusedNamespaceDeclarations(root);
58          return createDocument(root);
59      }
60  
61      protected Namespace getFeedNamespace() {
62          return RSS_NS;
63      }
64  
65      protected Namespace getRDFNamespace() {
66          return RDF_NS;
67      }
68  
69      protected Namespace getContentNamespace() {
70          return CONTENT_NS;
71      }
72  
73      protected Document createDocument(Element root) {
74          return new Document(root);
75      }
76  
77      protected Element createRootElement(Channel channel) {
78          Element root = new Element("RDF",getRDFNamespace());
79          root.addNamespaceDeclaration(getFeedNamespace());
80          root.addNamespaceDeclaration(getRDFNamespace());
81          root.addNamespaceDeclaration(getContentNamespace());
82          generateModuleNamespaceDefs(root);
83          return root;
84      }
85  
86      protected void populateFeed(Channel channel, Element parent) throws FeedException  {
87          addChannel(channel,parent);
88          addImage(channel,parent);
89          addTextInput(channel,parent);
90          addItems(channel,parent);
91          generateForeignMarkup(parent, (List)channel.getForeignMarkup());
92      }
93  
94      protected void addChannel(Channel channel,Element parent) throws FeedException {
95          Element eChannel = new Element("channel", getFeedNamespace());
96          populateChannel(channel,eChannel);
97          checkChannelConstraints(eChannel);
98          parent.addContent(eChannel);
99          generateFeedModules(channel.getModules(),eChannel);
100     }
101 
102     /***
103      * Populates the given channel with parsed data from the ROME element that holds the
104      * channel data.
105      *
106      * @param channel the channel into which parsed data will be added.
107      * @param eChannel the XML element that holds the data for the channel.
108      */
109     protected void populateChannel(Channel channel,Element eChannel) {
110         String title = channel.getTitle();
111         if (title!=null) {
112             eChannel.addContent(generateSimpleElement("title",title));
113         }
114         String link = channel.getLink();
115         if (link!=null) {
116             eChannel.addContent(generateSimpleElement("link",link));
117         }
118         String description = channel.getDescription();
119         if (description!=null) {
120             eChannel.addContent(generateSimpleElement("description",description));
121         }
122     }
123 
124     // maxLen == -1 means unlimited.
125     protected void checkNotNullAndLength(Element parent, String childName, int minLen, int maxLen) throws FeedException {
126         Element  child = parent.getChild(childName,getFeedNamespace());
127         if (child == null) {
128             throw new FeedException("Invalid "+getType()+" feed, missing "+parent.getName()+" "+childName);
129         }
130         checkLength(parent,childName,minLen,maxLen);
131     }
132 
133     // maxLen == -1 means unlimited.
134     protected void checkLength(Element parent, String childName, int minLen, int maxLen) throws FeedException {
135         Element  child = parent.getChild(childName,getFeedNamespace());
136         if (child != null) {
137             if (minLen>0 && child.getText().length()<minLen) {
138                 throw new FeedException("Invalid "+getType()+" feed, "+parent.getName()+" "+childName + "short of "+minLen+" length");
139             }
140             if (maxLen>-1 && child.getText().length()>maxLen) {
141                 throw new FeedException("Invalid "+getType()+" feed, "+parent.getName()+" "+childName + "exceeds "+maxLen+" length");
142             }
143         }
144     }
145 
146 
147     protected void addImage(Channel channel,Element parent) throws FeedException {
148         Image image = channel.getImage();
149         if (image!=null) {
150             Element eImage = new Element("image", getFeedNamespace());
151             populateImage(image,eImage);
152             checkImageConstraints(eImage);
153             parent.addContent(eImage);
154         }
155     }
156 
157     protected void populateImage(Image image,Element eImage) {
158         String title = image.getTitle();
159         if (title!=null) {
160             eImage.addContent(generateSimpleElement("title",title));
161         }
162         String url = image.getUrl();
163         if (url!=null) {
164             eImage.addContent(generateSimpleElement("url",url));
165         }
166         String link = image.getLink();
167         if (link!=null) {
168             eImage.addContent(generateSimpleElement("link",link));
169         }
170     }
171 
172     // Thxs DW for this one
173     protected String getTextInputLabel() {
174         return "textInput";
175     }
176 
177     protected void addTextInput(Channel channel,Element parent) throws FeedException {
178         TextInput textInput = channel.getTextInput();
179         if (textInput!=null) {
180             Element eTextInput = new Element(getTextInputLabel(), getFeedNamespace());
181             populateTextInput(textInput,eTextInput);
182             checkTextInputConstraints(eTextInput);
183             parent.addContent(eTextInput);
184         }
185     }
186 
187     protected void populateTextInput(TextInput textInput,Element eTextInput) {
188         String title = textInput.getTitle();
189         if (title!=null) {
190             eTextInput.addContent(generateSimpleElement("title",title));
191         }
192         String description = textInput.getDescription();
193         if (description!=null) {
194             eTextInput.addContent(generateSimpleElement("description",description));
195         }
196         String name = textInput.getName();
197         if (name!=null) {
198             eTextInput.addContent(generateSimpleElement("name",name));
199         }
200         String link = textInput.getLink();
201         if (link!=null) {
202             eTextInput.addContent(generateSimpleElement("link",link));
203         }
204     }
205 
206     protected void addItems(Channel channel,Element parent) throws FeedException {
207         List items = channel.getItems();
208         for (int i=0;i<items.size();i++) {
209             addItem((Item)items.get(i),parent, i);
210         }
211         checkItemsConstraints(parent);
212     }
213 
214     protected void addItem(Item item, Element parent, int index) throws FeedException {
215         Element eItem = new Element("item", getFeedNamespace());
216         populateItem(item,eItem, index);
217         checkItemConstraints(eItem);
218         generateItemModules(item.getModules(),eItem);
219         parent.addContent(eItem);
220     }
221 
222     protected void populateItem(Item item, Element eItem, int index) {
223         String title = item.getTitle();
224         if (title!=null) {
225             eItem.addContent(generateSimpleElement("title",title));
226         }
227         String link = item.getLink();
228         if (link!=null) {
229             eItem.addContent(generateSimpleElement("link",link));
230         }
231         generateForeignMarkup(eItem, (List)item.getForeignMarkup());
232     }
233 
234     protected Element generateSimpleElement(String name, String value) {
235         Element element = new Element(name, getFeedNamespace());
236         element.addContent(value);
237         return element;
238     }
239 
240     protected void checkChannelConstraints(Element eChannel) throws FeedException {
241         checkNotNullAndLength(eChannel,"title", 0, 40);
242         checkNotNullAndLength(eChannel,"description", 0, 500);
243         checkNotNullAndLength(eChannel,"link", 0, 500);
244     }
245 
246     protected void checkImageConstraints(Element eImage) throws FeedException {
247         checkNotNullAndLength(eImage,"title", 0, 40);
248         checkNotNullAndLength(eImage,"url", 0, 500);
249         checkNotNullAndLength(eImage,"link", 0, 500);
250     }
251 
252     protected void checkTextInputConstraints(Element eTextInput) throws FeedException {
253         checkNotNullAndLength(eTextInput,"title", 0, 40);
254         checkNotNullAndLength(eTextInput,"description", 0, 100);
255         checkNotNullAndLength(eTextInput,"name", 0, 500);
256         checkNotNullAndLength(eTextInput,"link", 0, 500);
257     }
258 
259     protected void checkItemsConstraints(Element parent) throws FeedException {
260         int count = parent.getChildren("item",getFeedNamespace()).size();
261         if (count<1 || count>15) {
262             throw new FeedException("Invalid "+getType()+" feed, item count is "+count+" it must be between 1 an 15");
263         }
264     }
265 
266     protected void checkItemConstraints(Element eItem) throws FeedException {
267         checkNotNullAndLength(eItem,"title", 0, 100);
268         checkNotNullAndLength(eItem,"link", 0, 500);
269     }
270 
271 }