gmane.comp.java.xstream.user

Re: Re: XStream ConversionException the second time I parse an XML file

Jörg Schaible — 2012-05-24T15:54:14

Hi,

Gonzalo Rodríguez Píriz wrote:


[snip]


Just in case you wonder: The converter tries to prevent the call of the 
(internal) comparator at all, since the elements are already in order and 
the call might have other unwanted side-effects.


In that case, I fear, it's Android only. Which XStream version you're using?


You're welcome,
Jörg


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Re: Re: XStream ConversionException the second time I parse an XML file

Gonzalo Rodríguez Píriz — 2012-05-24T14:54:40

On Thu, May 24, 2012 at 4:23 PM, Jörg Schaible
<Joerg.Schaible-ysaFb9yBoMtWk0Htik3J/w< at >public.gmane.org>wrote:

Thank you Jörg,

yes, that was what I though too :D

Definitely it's a problem with the TreeMap, I replaced it with a HashMap
and now it works all the time. Anyway, the TreeMap was very simple, I
didn't use a comparator and it didn't had any references, only pairs
key-value with Boolean, Integer and String values. If you want me to I can
try to reproduce it outside Android later and see if it crashes too.

Thanks for the help :)

Gonzalo.

Re: XStream ConversionException the second time I parse an XML file

Jörg Schaible — 2012-05-24T14:23:14

Hi Gonzalo,

Gonzalo Rodríguez Píriz wrote:

com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:79)
com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:65)
com.thoughtworks.xstream.converters.collections.TreeMapConverter.populateTreeMap(TreeMapConverter.java:150)

Basically, if you can read it once, you should be able to read it twice. ;-)

Can you try to reproduce this outside of Android? The TreeMapConverter does 
some really ugly hacks though. Do you use an own Comparator? Do your 
elements in the Map contain (indirect) references on the Map itself?

- Jörg


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XStream ConversionException the second time I parse an XML file

Gonzalo Rodríguez Píriz — 2012-05-24T10:13:05

Hi everyone,

I'm trying to read a TreeMap from an XML file using XStream (I previously
created the XML file using XStream too) in my Android application.

I simply do this in a static method of a class:

File f = new File(Environment.getExternalStorageDirectory(), "map.xml");

XStream xStream = new XStream(new DomDriver());

< at >SuppressWarnings("unchecked")
TreeMap<String,Object> map = (TreeMap<String,Object>) xStream.fromXML(f);

and then I use the values from the TreeMap with no problems... the first
time.

The thing is, if I invoke the method for a second time, it doesn't matter
if I do it just after the first execution or after a while, I get this:

05-24 08:33:53.404: E/AndroidRuntime(15543): FATAL EXCEPTION: main
05-24 08:33:53.404: E/AndroidRuntime(15543):
com.thoughtworks.xstream.converters.ConversionException: null : null
05-24 08:33:53.404: E/AndroidRuntime(15543): ---- Debugging information ----
05-24 08:33:53.404: E/AndroidRuntime(15543): cause-exception     :
java.lang.NullPointerException
05-24

RE: Re: Getting CannotResolveClassException

Jörg Schaible — 2012-05-24T07:20:01

Hi Anshuma,

Anshuma Ashok Goyal wrote:


You may try to use xstream.setClassloader before you call xstream.fromXML. 
However, I fear, that then the declared aliases may no longer match. In this 
case you have to bite the bullet and you will have to create the XStream 
instance every time in the correct thread.

- Jörg


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Re: Re: custom Map converter with XStreamImplicit anotation

Jörg Schaible — 2012-05-24T07:12:36

Hi Martin,

Martin Minka wrote:


Implicit declaration by annotation or API make no difference, its the 
implementation of the ReflectionProvider that skips your map in this case. 
All you can do is to write a custom converter for the type that contains 
this map.

- Jörg


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RE: Re: Getting CannotResolveClassException

Anshuma Ashok Goyal — 2012-05-24T04:32:32

Hi Jorg,



Thanks for your reply. Format of the CATEGORY_MAP_FILE has not changed. After debugging the issue I found that the below code is unable to load my class:



public class CompositeClassLoader extends ClassLoader {

...



public Class loadClass(String name) throws ClassNotFoundException {

        for (Iterator iterator = classLoaders.iterator(); iterator.hasNext();) {

            ClassLoader classLoader = (ClassLoader) iterator.next();

            try {

                return classLoader.loadClass(name);

            } catch (ClassNotFoundException notFound) {

                // ok.. try another one

            }

        }

        // One last try - the context class loader associated with the current thread. Often used in j2ee servers.

        // Note: The contextClassLoader cannot be added to the classLoaders list up front as the thread that constructs

        // XStream is potentially different to thread that uses it.

        ClassLoader contextCl

Re: Re: custom Map converter with XStreamImplicit anotation

Martin Minka — 2012-05-23T20:59:52

Jorg,
thank you for quick reply.

And is there a way for the converter to build output

<a id="map_key">map_value</a>

without implicit anotation ?
I don't need to use annotation, API would be also good.

Martin

2012/5/23 Jörg Schaible <joerg.schaible-Mmb7MZpHnFY< at >public.gmane.org>

Re: custom Map converter with XStreamImplicit anotation

Jörg Schaible — 2012-05-23T19:58:10

Hi Martin,

Martin Minka wrote:


No. Implicit collections/arrays/maps are a hack in the generic converters 
(e.g. ReflectionConverter) to skip the "implicit" container and write their 
elements like own elements. Therefore is no converter required/called for 
the map. Your converter is only called without the implicit declaration.

- Jörg


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custom Map converter with XStreamImplicit anotation

Martin Minka — 2012-05-23T18:55:36

I would like to produce from a HashMap following XML:
<a id="map_key">map_value</a>

I tried:
< at >XStreamImplicit(keyFieldName = "a")
< at >XStreamConverter(MyMapConverter.class)
HashMap<String, String> map = new HashMap<String, String>();

But this combination never enters MyMapConverter.

Is there a way to achieve this ?

Thank you.

Re: Getting CannotResolveClassException

Jörg Schaible — 2012-05-23T17:24:06

Hi,

Anshuma Ashok Goyal wrote:


The format of the CATEGORY_MAP_FILE has changed?


[snip]


Sorry, this is way too unspecific to say something else.

- Jörg


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Getting CannotResolveClassException

Anshuma Ashok Goyal — 2012-05-23T12:13:54

Hi Guys,

I am using com.thoughtworks.xstream v1.3.1.  And trying to load XML file to java object.

While doing so getting CannotResolveClassException error for the class CategoryRuleMap which is present at the required location.

This functionality was working with Sonar plugin api - 1.10. I have upgraded Sonar plugin api to 3.0 and this has stopped working. Any clue what could be the issue.

Below is the code snippet I have:

        InputStream input = getClass().getResourceAsStream(CATEGORY_MAP_FILE);
    categoryRuleMap = new CategoryRuleMap();

    XStream xstream = new XStream();
    xstream.alias("CategoryRuleMap", CategoryRuleMap.class);
    xstream.alias("category", CategoryMap.class);
    xstream.aliasAttribute(CategoryMap.class, "name", "name");
    xstream.alias("rule", String.class);
    xstream.addImplicitCollection(CategoryRuleMap.class, "categories");

    xstream.fromXML(input, categoryRuleMap);

Error trace:

 [INFO] Trace
com.thoughtworks.xstream.mapper.CannotResolveClassException: abc.de

Re: Jettison upgrade changes json

Jörg Schaible — 2012-05-13T15:01:09

Hi Andreas,

Andreas Sachs wrote:

{"name":"x","vorname":"y"}]}}}
{"name":"x","vorname":"y"}]}]}}

The JSON code produced by Jettison has slightly changed switching from 1.0.1 
to 1.2. If you had no problems until now, you should be able to use 1.0.1 
still. Jettison 1.1 and 1.3 are unfortunately creating a lot of problems and 
as of today all I can say is that they do not pass XStream's internal unit 
tests.

Cheers,
Jörg


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Jettison upgrade changes json

Andreas Sachs — 2012-05-13T00:41:28

Hi,
after upgrading xstream from 1.3.1 to 1.4.2 and jettison 1.0.1 to 1.2 (or 1.3.1) the generated json string changed. I could also change the javascript processing of the json string, but the new version looks strange to me.

I try to serialize the following object tree:

class userlist {
private List<User> users;
}

class User {
private name;
private vorname;
}


After the upgrade the json string contains collections at two different levels.

Old
{"userlist":{"users":{"user":[{"name":"x","vorname":"y"},{"name":"x","vorname":"y"}]}}}

New
{"userlist":{"users":[{"user":[{"name":"x","vorname":"y"},{"name":"x","vorname":"y"}]}]}}

Is this ok and i should change my code? or is this a bug?

Thanks
Andi



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Re: Re: configuring HibernateProxyConverter

Jörg Schaible — 2012-05-12T10:57:02

Hi Michael,

Michael Teixeira wrote:


well, it's simply, that at conversion time all converters are asked to 
convert this type in the reverse sequence they have been registered. The 
first converter that returns "true" for canConvert is taken. This is fine, 
since most converters handle distinct types.

However, some converters are more general e.g. ReflectionConverter, 
SerializableConverter or JavaBeanConverter. Since it would be problematic to 
add them again at the back of the registering chain, XStream supports a 
priority at registering time. This priority will modify the registration 
sequence by inserting the new converter before the first converter with same 
or lower priority.

By default all converters are registered with normal prio, converters that 
can handle multiple types in a generic way are usually using a low priority 
and something like the ReflectionConverter use lowest prop, since it is 
supposed to handle any type. It acts more or less as catch all.

Cheers,
Jörg


-----------------

Re: Re: configuring HibernateProxyConverter

Michael Teixeira — 2012-05-11T18:34:03

Thanks, yes, that seems to work.  So basically the requirement is that two
converters shouldn't run at the same priority - one should go ahead of
another?

Thanks for your help though, it's great, things are working.

Michael

On Thu, May 10, 2012 at 2:44 PM, Jörg Schaible <joerg.schaible-Mmb7MZpHnFY< at >public.gmane.org>wrote:

Re: Customizing JSON Map serialization

Jörg Schaible — 2012-05-11T08:36:23

Hi Pablo,

Pablo Pazos wrote:


Please have a look at the answer I gave Lynn some days ago. Following that 
recommendation will also solve your case.

Cheers,
Jörg


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Customizing JSON Map serialization

Pablo Pazos — 2012-05-11T00:58:15

Hi,

I'm trying to serialize to JSON an object that has a HashMap field, the
output is something like this:

"originalAuthor": [
            [
              "organisation",
              "Ocean Informatics"
            ],
            [
              "name",
              "Chunlan Ma"
            ],
            [
              "date",
              "16/11/2006"
            ]
          ]

But I expected something more like a JSON object:

"originalAuthor": {
              "organisation": "Ocean Informatics",
              "name": "Chunlan Ma",
              "date": "16/11/2006"
          }

This is a simple example, field values can be complex objects.


Is there some way of generating a structure like this for Map Java objects?

Thanks a lot.

Re: configuring HibernateProxyConverter

Jörg Schaible — 2012-05-10T18:44:16


And, by the way, since String has a default ctor, it is now handled by the 
JavaBeanConverter ... no wonder, that those tags are empty.

 
Cheers,
Jörg



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Re: configuring HibernateProxyConverter

Jörg Schaible — 2012-05-10T11:45:42

Hi Michael,

Michael Teixeira wrote:


You should register the JavaBeanConverter with low priority again, since it 
handles any type with a default constructor - except the onces that are 
handled by the later registered converters.



How does the class looks like that contains "abbrev"? Is the code snippet 
above all you do for configuring XStream? Any additional XStream annotations 
anywhere?

Cheers,
Jörg



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Re: configuring HibernateProxyConverter

Michael Teixeira — 2012-05-09T20:42:35

Jorg, Jaime,

Thanks for your time, thanks for your responses.

I did try also registering JavaBeanConverter.  The result was unexpected;
String properties weren't serialized.  Just Strings were omitted, the other
types, boolean, Boolean, user defined types, were serialized as usual.

I compared the serialization from 1.3.1 to 1.4.2, the diff shows:

4c4
<     <abbrev>ABG</abbrev>
---

where 'abbrev' is a String property; the data hasn't changed.  And so on,
there are many String properties, in many objects, as far as I can tell
none are serialized as they were previously.

I tried configuring XStream in various ways, the simplest is as follows:

        xstream = new XStream() {
            protected MapperWrapper wrapMapper(final MapperWrapper next) {
                return new HibernateMapper(next);
            }
        };
        xstream.registerConverter(new
JavaBeanConverter(xstream.getMapper()));
        xstream.registerConverter(new HibernateProxyConverter());
        xstream.registerConverter(new
H