Java XStream - How to ignore some elements

Question

I have the following XML:

<xml version="1.0" encoding="UTF-8"?> 
<osm version="0.6" generator="CGImap 0.0.2">
 <bounds minlat="48.1400000" minlon="11.5400000" maxlat="48.1450000" maxlon="11.5430000"/>
 <node id="398692" lat="48.1452196" lon="11.5414971" user="Peter14" uid="13832" visible="true" version="18" changeset="10762013" timestamp="2012-02-22T18:59:41Z">
 </node>
 <node id="1956100" lat="48.1434822" lon="11.5487963" user="Peter14" uid="13832" visible="true" version="41" changeset="10762013" timestamp="2012-02-22T18:59:39Z">
  <tag k="crossing" v="traffic_signals"/>
  <tag k="highway" v="traffic_signals"/>
  <tag k="TMC:cid_58:tabcd_1:Class" v="Point"/>
  <tag k="TMC:cid_58:tabcd_1:Direction" v="positive"/>
  <tag k="TMC:cid_58:tabcd_1:LCLversion" v="9.00"/>
  <tag k="TMC:cid_58:tabcd_1:LocationCode" v="35356"/>
  <tag k="TMC:cid_58:tabcd_1:NextLocationCode" v="35357"/>
  <tag k="TMC:cid_58:tabcd_1:PrevLocationCode" v="35355"/>
 </node>
</osm>

I just want to map the elements (node) to an object, but I'm having to problems:

1. It's complaining about bounds elements, because I don't want to map them.
2. Not all nodes have tags so I'm getting some issues with it.

Truculent

Well, please show your xml and maybe source code where you are setting up xstream – Belter

Answer 1

Unfortunately overriding Mapper behaviour mentioned here does not work with implicit collections or annotations. I checked with version 1.4.3. So the obvious solution I found was to mock ignored fields with ommiting annotation. Works perfect for me but a bit boring to create them every time.

@XStreamOmitField
private Object ignoredElement;

Milliard

Or, alternatively, you can also do: xStream.omitField(ClassName.class,"fieldName"); – Fold

Answer 2

Since XStream 1.4.5 durring marshaller declaration it's enough to use ignoreEnknownElements() method:

XStreamMarshaller marshaller = new XStreamMarshaller();
marshaller.getXStream().ignoreUnknownElements();
...

to ignore unnecessary elements.

Costive

Answer 3

Simply define below anonymous class after Xtream deceleration.

XStream xstream = new XStream(new DomDriver()){  
            protected MapperWrapper wrapMapper(MapperWrapper next) {
                return new MapperWrapper(next) {
                    public boolean shouldSerializeMember(Class definedIn, String fieldName) {
                        try {
                            return definedIn != Object.class || realClass(fieldName) != null;
                        } catch(CannotResolveClassException cnrce) {
                            return false;
                        }
                    }
                };
            }
        };

Lamoreaux

Answer 4

you can do that by overriding the default marshaller.

import org.springframework.oxm.xstream.XStreamMarshaller;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.mapper.MapperWrapper;

public class CustomXStreamMarshaller extends XStreamMarshaller {

@Override
protected XStream constructXStream() {
    // The referenced XStream constructor has been deprecated as of 1.4.5.
    // We're preserving this call for broader XStream 1.4.x compatibility.
    return new XStream() {
        @Override
        protected MapperWrapper wrapMapper(MapperWrapper next) {
                return new MapperWrapper(next) {
                    @Override
                    public boolean shouldSerializeMember(Class definedIn, String fieldName) {
                        if (definedIn == Object.class) {
                            return false;
                        }
                        return super.shouldSerializeMember(definedIn, fieldName);
                    }
                };
        }
    };
}}

Manoeuvre

Answer 5

Plain googling reveals a lot of ioptions. This is one of them:

http://rafaelsteil.com/omit-unexpected-xml-elements-with-xstream/

Belter