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1   package com.sun.syndication.io.impl;
2   
3   import com.sun.syndication.io.WireFeedGenerator;
4   import org.jdom.Element;
5   import org.jdom.Namespace;
6   import org.jdom.Parent;
7   
8   import java.util.HashSet;
9   import java.util.Iterator;
10  import java.util.List;
11  import java.util.Set;
12  
13  /***
14   * @author Alejandro Abdelnur
15   */
16  public abstract class BaseWireFeedGenerator implements WireFeedGenerator {
17  
18      /***
19       * [TYPE].feed.ModuleParser.classes=  [className] ...
20       */
21      private static final String FEED_MODULE_GENERATORS_POSFIX_KEY = ".feed.ModuleGenerator.classes";
22  
23      /***
24       * [TYPE].item.ModuleParser.classes= [className] ...
25       */
26      private static final String ITEM_MODULE_GENERATORS_POSFIX_KEY = ".item.ModuleGenerator.classes";
27  
28  
29      private String _type;
30      private ModuleGenerators _feedModuleGenerators;
31      private ModuleGenerators _itemModuleGenerators;
32      private Namespace[] _allModuleNamespaces;
33  
34      protected BaseWireFeedGenerator(String type) {
35          _type = type;
36          _feedModuleGenerators = new ModuleGenerators(type + FEED_MODULE_GENERATORS_POSFIX_KEY, this);
37          _itemModuleGenerators = new ModuleGenerators(type + ITEM_MODULE_GENERATORS_POSFIX_KEY, this);
38          Set allModuleNamespaces = new HashSet();
39          Iterator i = _feedModuleGenerators.getAllNamespaces().iterator();
40          while (i.hasNext()) {
41              allModuleNamespaces.add(i.next());
42          }
43          i = _itemModuleGenerators.getAllNamespaces().iterator();
44          while (i.hasNext()) {
45              allModuleNamespaces.add(i.next());
46          }
47          _allModuleNamespaces = new Namespace[allModuleNamespaces.size()];
48          allModuleNamespaces.toArray(_allModuleNamespaces);
49      }
50  
51      public String getType() {
52          return _type;
53      }
54  
55      protected void generateModuleNamespaceDefs(Element root) {
56          for (int i = 0; i < _allModuleNamespaces.length; i++) {
57              root.addNamespaceDeclaration(_allModuleNamespaces[i]);
58          }
59      }
60  
61      protected void generateFeedModules(List modules, Element feed) {
62          _feedModuleGenerators.generateModules(modules, feed);
63      }
64  
65      public void generateItemModules(List modules, Element item) {
66          _itemModuleGenerators.generateModules(modules, item);
67      }
68  
69      protected void generateForeignMarkup(Element e, List foreignMarkup) {
70          if (foreignMarkup != null) {
71              Iterator elems = (Iterator) foreignMarkup.iterator();
72              while (elems.hasNext()) {
73                  Element elem = (Element) elems.next();
74                  Parent parent = elem.getParent();
75                  if (parent != null) {
76                      parent.removeContent(elem);
77                  }
78                  e.addContent(elem);
79              }
80          }
81      }
82  
83      /***
84       * Purging unused declarations is less optimal, performance-wise, than never adding them in the first place.  So, we
85       * should still ask the ROME guys to fix their code (not adding dozens of unnecessary module declarations). Having
86       * said that: purging them here, before XML generation, is more efficient than parsing and re-molding the XML after
87       * ROME generates it.
88       * <p/>
89       * Note that the calling app could still add declarations/modules to the Feed tree after this.  Which is fine.  But
90       * those modules are then responsible for crawling to the root of the tree, at generate() time, to make sure their
91       * namespace declarations are present.
92       */
93      protected static void purgeUnusedNamespaceDeclarations(Element root) {
94          java.util.Set usedPrefixes = new java.util.HashSet();
95          collectUsedPrefixes(root, usedPrefixes);
96  
97          List list = root.getAdditionalNamespaces();
98          List additionalNamespaces = new java.util.ArrayList();
99          additionalNamespaces.addAll(list); // the duplication will prevent a ConcurrentModificationException below
100 
101         for (int i = 0; i < additionalNamespaces.size(); i++) {
102             Namespace ns = (Namespace) additionalNamespaces.get(i);
103             String prefix = ns.getPrefix();
104             if (prefix != null && prefix.length() > 0 && !usedPrefixes.contains(prefix)) {
105                 root.removeNamespaceDeclaration(ns);
106             }
107         }
108     }
109 
110     private static void collectUsedPrefixes(Element el, java.util.Set collector) {
111         String prefix = el.getNamespacePrefix();
112         if (prefix != null && prefix.length() > 0 && !collector.contains(prefix)) {
113             collector.add(prefix);
114         }
115         List kids = el.getChildren();
116         for (int i = 0; i < kids.size(); i++) {
117             collectUsedPrefixes((Element) kids.get(i), collector); // recursion - worth it
118         }
119     }
120 
121 }