Details
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Type:
Bug
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Status:
Closed
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Resolution: Fixed
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Affects Version/s: None
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Fix Version/s: 1.1.2
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Component/s: None
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Labels:None
Description
getValue() seems to mess-up the lookahead queue.
In a converter, when unmarshalling:
...
reader.getValue();
while (reader.hasMoreChildren()) {
reader.moveDown();//this may fail there is no text
context.convertAnother(...);
reader.moveUp();
}
First lookahead() is called from getValue() but there is no text event. However, whatever event it was, it will be gone for the next lookahead() call (from hasMoreChildren()).
Another way to see this is to call reader.getValue() multiple times.
Activity
Here's an integrated test case:
import java.io.FileReader;
import java.io.FileWriter;
import java.util.LinkedList;
import java.util.List;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
public class XStreamTest {
public static void main(String[] args) {
XStream xs = new XStream();
xs.registerConverter(new TestConverter());
TestClass test = new TestClass();
//change to true to see the problem
boolean bug = false;
if (bug)
else
{ test.value = "some text"; } test.children.add("one");
test.children.add("two");
try
catch (Exception e)
{ e.printStackTrace(); }}
public static class TestConverter implements Converter {
public boolean canConvert(Class cls)
{ return TestClass.class.equals(cls); }public void marshal(Object obj, HierarchicalStreamWriter writer, MarshallingContext context)
{ TestClass test = (TestClass) obj; writer.setValue(test.value); context.convertAnother(test.children); } public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {
TestClass test = new TestClass();
//in 'bug mode' reader.hadMoreChildren() will return false the first time
test.value = reader.getValue();
//Uncomment the lines below to get an exception for both values of 'bug' above
//test.value = reader.getValue();
//test.value = reader.getValue();
//test.value = reader.getValue();
while (reader.hasMoreChildren())
{ reader.moveDown(); System.out.println(reader.getNodeName()); reader.moveUp(); } return test;
}
}
public static class TestClass
{ public String value; public List children = new LinkedList(); }}
Mihael Hategan
added a comment - Here's an integrated test case:
import java.io.FileReader;
import java.io.FileWriter;
import java.util.LinkedList;
import java.util.List;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
public class XStreamTest {
public static void main(String[] args) {
XStream xs = new XStream();
xs.registerConverter(new TestConverter());
TestClass test = new TestClass();
//change to true to see the problem
boolean bug = false;
if (bug)
{
test.value = "";
}
else
{
test.value = "some text";
}
test.children.add("one");
test.children.add("two");
try
{
FileWriter out = new FileWriter("test.xml");
xs.toXML(test, out);
out.close();
FileReader in = new FileReader("test.xml");
xs.fromXML(in);
in.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
public static class TestConverter implements Converter {
public boolean canConvert(Class cls)
{
return TestClass.class.equals(cls);
}
public void marshal(Object obj, HierarchicalStreamWriter writer, MarshallingContext context)
{
TestClass test = (TestClass) obj;
writer.setValue(test.value);
context.convertAnother(test.children);
}
public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {
TestClass test = new TestClass();
//in 'bug mode' reader.hadMoreChildren() will return false the first time
test.value = reader.getValue();
//Uncomment the lines below to get an exception for both values of 'bug' above
//test.value = reader.getValue();
//test.value = reader.getValue();
//test.value = reader.getValue();
while (reader.hasMoreChildren())
{
reader.moveDown();
System.out.println(reader.getNodeName());
reader.moveUp();
}
return test;
}
}
public static class TestClass
{
public String value;
public List children = new LinkedList();
}
} Fixed by Joe, no further comment from reporter.
Jörg Schaible
added a comment - Fixed by Joe, no further comment from reporter. 
Could you provide some sample XML for this.
thanks
-Joe