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1   /*
2    * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
21   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22   * or visit www.oracle.com if you need additional information or have any
23   * questions.
24   */
25  
26  package com.sun.xml.internal.bind.v2.runtime;
27  
28  import java.util.HashMap;
29  
30  import javax.xml.bind.ValidationEvent;
31  import javax.xml.bind.ValidationEventHandler;
32  import javax.xml.bind.ValidationEventLocator;
33  import javax.xml.bind.annotation.adapters.XmlAdapter;
34  import javax.xml.bind.helpers.ValidationEventImpl;
35  
36  import com.sun.xml.internal.bind.v2.ClassFactory;
37  import com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext;
38  
39  import org.xml.sax.ErrorHandler;
40  import org.xml.sax.SAXException;
41  import org.xml.sax.SAXParseException;
42  
43  /**
44   * Object that coordinates the marshalling/unmarshalling.
45   *
46   * <p>
47   * This class takes care of the logic that allows code to obtain
48   * {@link UnmarshallingContext} and {@link XMLSerializer} instances
49   * during the unmarshalling/marshalling.
50   *
51   * <p>
52   * This is done by using a {@link ThreadLocal}. Therefore one unmarshalling/marshalling
53   * episode has to be done from the beginning till end by the same thread.
54   * (Note that the same {@link Coordinator} can be then used by a different thread
55   * for an entirely different episode.)
56   *
57   * This class also maintains the user-configured instances of {@link XmlAdapter}s.
58   *
59   * <p>
60   * This class implements {@link ErrorHandler} and propages erros to this object
61   * as the {@link ValidationEventHandler}, which will be implemented in a derived class.
62   *
63   * @author Kohsuke Kawaguchi
64   */
65  public abstract class Coordinator implements ErrorHandler, ValidationEventHandler {
66  
67      private final HashMap<Class<? extends XmlAdapter>,XmlAdapter> adapters =
68              new HashMap<Class<? extends XmlAdapter>,XmlAdapter>();
69  
70  
71      public final XmlAdapter putAdapter(Class<? extends XmlAdapter> c, XmlAdapter a) {
72          if(a==null)
73              return adapters.remove(c);
74          else
75              return adapters.put(c,a);
76      }
77  
78      /**
79       * Gets the instance of the adapter.
80       *
81       * @return
82       *      always non-null.
83       */
84      public final <T extends XmlAdapter> T getAdapter(Class<T> key) {
85          T v = key.cast(adapters.get(key));
86          if(v==null) {
87              v = ClassFactory.create(key);
88              putAdapter(key,v);
89          }
90          return v;
91      }
92  
93      public <T extends XmlAdapter> boolean containsAdapter(Class<T> type) {
94          return adapters.containsKey(type);
95      }
96  
97      // this much is necessary to avoid calling get and set twice when we push.
98      private static final ThreadLocal<Coordinator> activeTable = new ThreadLocal<Coordinator>();
99  
100     /**
101      * The {@link Coordinator} in charge before this {@link Coordinator}.
102      */
103     private Coordinator old;
104 
105     /**
106      * Called whenever an execution flow enters the realm of this {@link Coordinator}.
107      */
108     protected final void pushCoordinator() {
109         old = activeTable.get();
110         activeTable.set(this);
111     }
112 
113     /**
114      * Called whenever an execution flow exits the realm of this {@link Coordinator}.
115      */
116     protected final void popCoordinator() {
117         if (old != null)
118             activeTable.set(old);
119         else
120             activeTable.remove();
121         old = null; // avoid memory leak
122     }
123 
124     public static Coordinator _getInstance() {
125         return activeTable.get();
126     }
127 
128 //
129 //
130 // ErrorHandler implementation
131 //
132 //
133     /**
134      * Gets the current location. Used for reporting the error source location.
135      */
136     protected abstract ValidationEventLocator getLocation();
137 
138     public final void error(SAXParseException exception) throws SAXException {
139         propagateEvent( ValidationEvent.ERROR, exception );
140     }
141 
142     public final void warning(SAXParseException exception) throws SAXException {
143         propagateEvent( ValidationEvent.WARNING, exception );
144     }
145 
146     public final void fatalError(SAXParseException exception) throws SAXException {
147         propagateEvent( ValidationEvent.FATAL_ERROR, exception );
148     }
149 
150     private void propagateEvent( int severity, SAXParseException saxException )
151         throws SAXException {
152 
153         ValidationEventImpl ve =
154             new ValidationEventImpl( severity, saxException.getMessage(), getLocation() );
155 
156         Exception e = saxException.getException();
157         if( e != null ) {
158             ve.setLinkedException( e );
159         } else {
160             ve.setLinkedException( saxException );
161         }
162 
163         // call the client's event handler.  If it returns false, then bail-out
164         // and terminate the unmarshal operation.
165         boolean result = handleEvent( ve );
166         if( ! result ) {
167             // bail-out of the parse with a SAX exception, but convert it into
168             // an UnmarshalException back in in the AbstractUnmarshaller
169             throw saxException;
170         }
171     }
172 }