CompositeObjectFactory


1   package org.sapia.util.xml.confix;
2   
3   
4   // Import of Sun's JDK classes
5   // ---------------------------
6   import java.util.HashMap  ;
7   import java.util.Map  ;
8   
9   
10  /**
11   * This instance implements an <code>ObjectFactoryIF</code> that internally
12   * maps child object factories to XML namepspace prefixes OR URIs.
13   *
14   * @author Jean-Cedric Desrochers
15   *
16   * <dl>
17   * <dt><b>Copyright:</b><dd>Copyright &#169; 2002-2003 <a HREF="http://www.sapia-oss.org">Sapia Open Source Software</a>. All Rights Reserved.</dd></dt>
18   * <dt><b>License:</b><dd>Read the license.txt file of the jar or visit the
19   *        <a HREF="http://www.sapia-oss.org/license.html">license page</a> at the Sapia OSS web site</dd></dt>
20   * </dl>
21   */
22  public class CompositeObjectFactory implements ObjectFactoryIF {
23    /////////////////////////////////////////////////////////////////////////////////////////
24    /////////////////////////////////  INSTANCE ATTRIBUTES  /////////////////////////////////
25    /////////////////////////////////////////////////////////////////////////////////////////
26  
27    /** The map of object factories identified by the namespace thei manage. */
28    private Map   _theFactories;
29  
30    /**
31     * If true, indicates that factories are mapped to prefixes - else to the namespace URI.
32     * Defaults to false.
33     */
34    private boolean _mapToNameSpacePrefix = false;
35  
36    /////////////////////////////////////////////////////////////////////////////////////////
37    ////////////////////////////////////  CONSTRUCTORS  /////////////////////////////////////
38    /////////////////////////////////////////////////////////////////////////////////////////
39  
40    /**
41     * Creates a new CompositeObjectFactory instance.
42     */
43    public CompositeObjectFactory() {
44      _theFactories = new HashMap  ();
45    }
46  
47    /**
48     * Indicates if internal factories are mapped to namespace URIs or
49     * prefixes; if <code>true</code>, object factories are mapped to
50     * prefixes. By default, an instance of this class maps object factories
51     * to the URI.
52     *
53     * @param mapToPrefix if <code>true</code>, object factories are mapped to
54     * prefixes.
55     */
56    public void setMapToPrefix(boolean mapToPrefix) {
57      _mapToNameSpacePrefix = mapToPrefix;
58    }
59  
60    /////////////////////////////////////////////////////////////////////////////////////////
61    ///////////////////////////////////  MUTATOR METHODS  ///////////////////////////////////
62    /////////////////////////////////////////////////////////////////////////////////////////
63  
64    /**
65     * Registers the object factory passed in for the namespace URI passed in.
66     *
67     * @param aNamespaceURIorPrefix The namespace URI or prefix to associate with the factory.
68     * @param aFactory The object factory to register.
69     * @exception IllegalArgumentExcption If a factory is already registered for
70     *            the passed in namespace URI.
71     */
72    public void registerFactory(String   aNamespaceURIorPrefix,
73      ObjectFactoryIF aFactory) {
74      if (_theFactories.containsKey(aNamespaceURIorPrefix)) {
75        throw new IllegalArgumentException  (
76          "An object factory is already registered for the namespace URI or prefix " +
77          aNamespaceURIorPrefix);
78      }
79  
80      _theFactories.put(aNamespaceURIorPrefix, aFactory);
81    }
82  
83    /**
84     * Returns the child object factory internally mapped to the given namespace or
85     * prefix.
86     *
87     * @return an <code>ObjectFactoryIF</code>.
88     * @param aNamespaceURIorPrefix a XML namepsace prefix or URI.
89     * @throws IllegalArgumentException if no factory can be found for the given
90     * namespace of prefix.
91     */
92    public ObjectFactoryIF getFactoryFor(String   aNamespaceURIorPrefix)
93      throws IllegalArgumentException   {
94      ObjectFactoryIF fac = (ObjectFactoryIF) _theFactories.get(aNamespaceURIorPrefix);
95  
96      if (fac == null) {
97        throw new IllegalArgumentException  (
98          "No object factory registered for the namespace URI or prefix " +
99          aNamespaceURIorPrefix);
100     }
101 
102     return fac;
103   }
104 
105   /**
106    * Returns true if an object factory is internally mapped to the given
107    * namespace or prefix.
108    *
109    * @return <code>true</code> if an object factory is internally mapped to the given
110    * namespace or prefix.
111    */
112   public boolean containsObjectFactory(String   aNamespaceURIorPrefix) {
113     return _theFactories.get(aNamespaceURIorPrefix) != null;
114   }
115 
116   /////////////////////////////////////////////////////////////////////////////////////////
117   //////////////////////////////  INTERFACE IMPLEMENTATION  ///////////////////////////////
118   /////////////////////////////////////////////////////////////////////////////////////////
119 
120   /**
121    * Creates an object for the element passed in. This method in fact delegates
122    * object creation logic to the factory that is mapped to the given namespace OR prefix.
123    * Whether this method uses the namespace or prefix depends on the flag that was set
124    * through this instance's <code>setMapToPrefix(...)</code> method.
125    *
126    * @param aPrefix The namespace prefix of the element.
127    * @param aNamespaceURI The namespace URI of the element.
128    * @param anElementName The element name for wich to create an object.
129    * @param aParent The parent object of the object to create.
130    * @see #setMapToPrefix(boolean)
131    * @exception ObjectCreationException If an error occurs creating the object.
132    */
133   public CreationStatus newObjectFor(String   aPrefix, String   aNamespaceURI,
134     String   anElementName, Object   aParent) throws ObjectCreationException {
135     ObjectFactoryIF aFactory;
136 
137     if (_mapToNameSpacePrefix) {
138       if ((aPrefix == null) || (aPrefix.length() == 0)) {
139         throw new ObjectCreationException("Prefix no defined");
140       }
141 
142       aFactory = (ObjectFactoryIF) _theFactories.get(aPrefix);
143     } else {
144       if ((aNamespaceURI == null) || (aNamespaceURI.length() == 0)) {
145         throw new ObjectCreationException("Namespace no defined");
146       }
147 
148       aFactory = (ObjectFactoryIF) _theFactories.get(aNamespaceURI);
149     }
150 
151     if (aFactory == null) {
152       throw new ObjectCreationException("No factory found for the namespace " +
153         aNamespaceURI);
154     } else {
155       return aFactory.newObjectFor(aPrefix, aNamespaceURI, anElementName,
156         aParent);
157     }
158   }
159 }
160
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