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1 package com.thoughtworks.xstream.converters.reflection;
2
3 import com.thoughtworks.xstream.converters.ConversionException;
4 import com.thoughtworks.xstream.converters.Converter;
5 import com.thoughtworks.xstream.converters.MarshallingContext;
6 import com.thoughtworks.xstream.converters.UnmarshallingContext;
7 import com.thoughtworks.xstream.core.util.CustomObjectInputStream;
8 import com.thoughtworks.xstream.core.util.CustomObjectOutputStream;
9 import com.thoughtworks.xstream.io.HierarchicalStreamReader;
10 import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
11 import com.thoughtworks.xstream.mapper.Mapper;
12
13 import java.io.Externalizable  ;
14 import java.io.IOException ;
15 import java.io.NotActiveException ;
16 import java.io.ObjectInput ;
17 import java.io.ObjectInputValidation ;
18 import java.io.ObjectOutput ;
19 import java.util.Map ;
20
21
27 public class ExternalizableConverter implements Converter {
28
29 private Mapper mapper;
30
31 public ExternalizableConverter(Mapper mapper) {
32 this.mapper = mapper;
33 }
34
35 public boolean canConvert(Class type) {
36 return Externalizable .class.isAssignableFrom(type);
37 }
38
39 public void marshal(Object source, final HierarchicalStreamWriter writer, final MarshallingContext context) {
40 try {
41 Externalizable externalizable = (Externalizable ) source;
42 CustomObjectOutputStream.StreamCallback callback = new CustomObjectOutputStream.StreamCallback() {
43 public void writeToStream(Object object) {
44 if (object == null) {
45 writer.startNode("null");
46 writer.endNode();
47 } else {
48 writer.startNode(mapper.serializedClass(object.getClass()));
49 context.convertAnother(object);
50 writer.endNode();
51 }
52 }
53
54 public void writeFieldsToStream(Map fields) {
55 throw new UnsupportedOperationException ();
56 }
57
58 public void defaultWriteObject() {
59 throw new UnsupportedOperationException ();
60 }
61
62 public void flush() {
63 writer.flush();
64 }
65
66 public void close() {
67 throw new UnsupportedOperationException ("Objects are not allowed to call ObjecOutput.close() from writeExternal()");
68 }
69 };
70 ObjectOutput objectOutput = CustomObjectOutputStream.getInstance(context, callback);
71 externalizable.writeExternal(objectOutput);
72 } catch (IOException e) {
73 throw new ConversionException("Cannot serialize " + source.getClass().getName() + " using Externalization", e);
74 }
75 }
76
77 public Object unmarshal(final HierarchicalStreamReader reader, final UnmarshallingContext context) {
78 final Class type = context.getRequiredType();
79 try {
80 Externalizable externalizable = (Externalizable ) type.newInstance();
81 CustomObjectInputStream.StreamCallback callback = new CustomObjectInputStream.StreamCallback() {
82 public Object readFromStream() {
83 reader.moveDown();
84 Object streamItem = context.convertAnother(type, mapper.realClass(reader.getNodeName()));
85 reader.moveUp();
86 return streamItem;
87 }
88
89 public Map readFieldsFromStream() {
90 throw new UnsupportedOperationException ();
91 }
92
93 public void defaultReadObject() {
94 throw new UnsupportedOperationException ();
95 }
96
97 public void registerValidation(ObjectInputValidation validation, int priority) throws NotActiveException {
98 throw new NotActiveException ("stream inactive");
99 }
100
101 public void close() {
102 throw new UnsupportedOperationException ("Objects are not allowed to call ObjectInput.close() from readExternal()");
103 }
104 };
105 ObjectInput objectInput = CustomObjectInputStream.getInstance(context, callback);
106 externalizable.readExternal(objectInput);
107 return externalizable;
108 } catch (InstantiationException e) {
109 throw new ConversionException("Cannot construct " + type.getClass(), e);
110 } catch (IllegalAccessException e) {
111 throw new ConversionException("Cannot construct " + type.getClass(), e);
112 } catch (IOException e) {
113 throw new ConversionException("Cannot externalize " + type.getClass(), e);
114 } catch (ClassNotFoundException e) {
115 throw new ConversionException("Cannot externalize " + type.getClass(), e);
116 }
117 }
118 }
119 |
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