Details
-
Type:
Bug
-
Status:
Closed
-
Priority:
Major
-
Resolution: Fixed
-
Affects Version/s: 1.2.2
-
Fix Version/s: 1.3
-
Component/s: Converters, Core
-
Labels:None
-
JDK version and platform:Sun 1.5.0_11 for Windows
Description
Below is the minimal case for the problem I came across. During deserialization NPE is thrown from compareTo method, probably because object is put in the tree before id is filled. Simple workaround is to change the order of the fields, but sometimes it's not possible (for example when field is inherited).
import java.util.Set;
import java.util.TreeSet;
import junit.framework.TestCase;
import com.thoughtworks.xstream.XStream;
public class Test extends TestCase {
XStream xs = new XStream();
public void test()
{ C c = new C(1); c.others.add(c); c.others.add(new C(2)); xs.fromXML(xs.toXML(c)); }}
class C implements Comparable {
Set<C> others = new TreeSet<C>();
final Integer id;
C(Integer id)
{ this.id = id; }public int compareTo(Object o)
{ return id.compareTo(((C) o).id); }}
Activity
This modified case fails regardless of field order:
import java.util.Set;
import java.util.TreeSet;
import junit.framework.TestCase;
import com.thoughtworks.xstream.XStream;
public class Test extends TestCase {
XStream xs = new XStream();
public void test()
{ C c = new C(1); c.others.add(c); c.others.add(new C(1)); /* same id */ xs.fromXML(xs.toXML(c)); }}
class C implements Comparable {
final Integer id;
final Set<C> others = new TreeSet<C>();
C(Integer id)
{ this.id = id; } public int compareTo(Object o) {
C c = (C) o;
int cmp = id.compareTo(c.id);
if (cmp != 0)
else
{ return new Integer(others.size()).compareTo(c.others.size()); } }
}
jsmyczek
added a comment - This modified case fails regardless of field order:
import java.util.Set;
import java.util.TreeSet;
import junit.framework.TestCase;
import com.thoughtworks.xstream.XStream;
public class Test extends TestCase {
XStream xs = new XStream();
public void test()
{
C c = new C(1);
c.others.add(c);
c.others.add(new C(1)); /* same id */
xs.fromXML(xs.toXML(c));
}
}
class C implements Comparable {
final Integer id;
final Set<C> others = new TreeSet<C>();
C(Integer id)
{
this.id = id;
}
public int compareTo(Object o) {
C c = (C) o;
int cmp = id.compareTo(c.id);
if (cmp != 0)
{
return cmp;
}
else
{
return new Integer(others.size()).compareTo(c.others.size());
}
}
} You're right, your second case also failed with the head revision. I've tested the same case with JDK serialization and had to recognize that they succeed. Main reason was, that the JDK contains an optimized functionality when a presorted set is added into an empty TreeSet. I changed the implementation of the TreeSetConverter (and TreeMapConverter) to behave the same. You may give the latest head revision a try.
Jörg Schaible
added a comment - You're right, your second case also failed with the head revision. I've tested the same case with JDK serialization and had to recognize that they succeed. Main reason was, that the JDK contains an optimized functionality when a presorted set is added into an empty TreeSet. I changed the implementation of the TreeSetConverter (and TreeMapConverter) to behave the same. You may give the latest head revision a try. Closing issues before next release.
Jörg Schaible
added a comment - Closing issues before next release. 
Since XStream 1.2.2 you can set the order in which the fields are saved (see FAQ). Starting with 1.3 the inherited fields will be saved first (see announcement of 1.2.2 release).