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1 package com.thoughtworks.xstream.core;
2
3 import com.thoughtworks.xstream.alias.ClassMapper;
4 import com.thoughtworks.xstream.converters.Converter;
5 import com.thoughtworks.xstream.converters.ConverterLookup;
6 import com.thoughtworks.xstream.converters.MarshallingContext;
7 import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
8
9 import java.util.Collection  ;
10 import java.util.HashSet ;
11
12 public class TreeMarshaller implements MarshallingContext {
13
14 protected HierarchicalStreamWriter writer;
15 protected ConverterLookup converterLookup;
16 protected ClassMapper classMapper;
17 private Collection parentObjects = new HashSet ();
18
19 public TreeMarshaller(HierarchicalStreamWriter writer, ConverterLookup converterLookup,
20 ClassMapper classMapper) {
21 this.writer = writer;
22 this.converterLookup = converterLookup;
23 this.classMapper = classMapper;
24 }
25
26 public void convertAnother(Object item) {
27 Integer id = new Integer (System.identityHashCode(item));
28 if (parentObjects.contains(id)) {
29 throw new CircularReferenceException();
30 }
31 parentObjects.add(id);
32 Converter converter = converterLookup.lookupConverterForType(item.getClass());
33 converter.marshal(item, writer, this);
34 parentObjects.remove(id);
35 }
36
37 public void start(Object item) {
38 if (item == null) {
39 writer.startNode(classMapper.lookupName(ClassMapper.Null.class));
40 writer.endNode();
41 } else {
42 writer.startNode(classMapper.lookupName(item.getClass()));
43 convertAnother(item);
44 writer.endNode();
45 }
46 }
47
48 public class CircularReferenceException extends RuntimeException {
49 }
50
51 }
52 |
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