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1   /*
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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
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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
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19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
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24   */
25  
26  package com.sun.xml.internal.bind;
27  
28  import javax.xml.bind.Marshaller;
29  
30  /**
31   * Optional interface that can be implemented by JAXB-bound objects
32   * to handle cycles in the object graph.
33   *
34   * <p>
35   * As discussed in <a href="https://jaxb.dev.java.net/guide/Mapping_cyclic_references_to_XML.html">
36   * the users' guide</a>, normally a cycle in the object graph causes the marshaller to report an error,
37   * and when an error is found, the JAXB RI recovers by cutting the cycle arbitrarily.
38   * This is not always a desired behavior.
39   *
40   * <p>
41   * Implementing this interface allows user application to change this behavior.
42   * Also see <a href="http://forums.java.net/jive/thread.jspa?threadID=13670">this related discussion</a>.
43   *
44   * @since JAXB 2.1 EA2
45   * @author Kohsuke Kawaguchi
46   */
47  public interface CycleRecoverable {
48      /**
49       * Called when a cycle is detected by the JAXB RI marshaller
50       * to nominate a new object to be marshalled instead.
51       *
52       * @param context
53       *      This object is provided by the JAXB RI to inform
54       *      the object about the marshalling process that's going on.
55       *
56       *
57       * @return
58       *      the object to be marshalled instead of <tt>this</tt> object.
59       *      Or return null to indicate that the JAXB RI should behave
60       *      just like when your object does not implement {@link CycleRecoverable}
61       *      (IOW, cut the cycle arbitrarily and try to go on.)
62       */
63      Object onCycleDetected(Context context);
64  
65      /**
66       * This interface is implemented by the JAXB RI to provide
67       * information about the on-going marshalling process.
68       *
69       * <p>
70       * We may add more methods in the future, so please do not
71       * implement this interface in your application.
72       */
73      public interface Context {
74          /**
75           * Returns the marshaller object that's doing the marshalling.
76           *
77           * @return
78           *      always non-null.
79           */
80          Marshaller getMarshaller();
81      }
82  }