xstream使用Converter将复杂的XML反序列化为更简单的Java

Question

I have surely a problem of understanding of Xstream converter.

I have a pretty complex XML coming from legacy back office application and a just want to convert this one into a simpler java class or a Map with Converter.

1. I do not want to marshal to XML, just unmarshal
2. I do not want to use annotation, just KISS

My XML is like

<root>
    <agent>
        <id>123456789</id>
        <name>GABIN</name>
        <forname>Jean</forname>
        <unit>
            <legacyReference>AA</legacyReference>
            <name>SAN ANTONIO</name>
            <legacyName>SA</legacyName>
            <address>
                <number>1</number>
                <street>Sesam street</street>
                <city>NoWhere</city>
                <legacyID>AAZE-56</legacyID>
            </address>
            <legacyStructurBlablabla>
                <type>OFFICE</type>
                <data>
                    <foo>BAR</foo> 
                </data>
            </legacyStructurBlablabla>
            <...>
        </unit>
        <...> 
    </agent>
</root>

My destination class is very simple

class Agent {
    String id;
    String name;
    String forname;
    String unitName;
    String unitType;
    <...>

}

My main method looks like

xStream = new XStream(new DomDriver());
stream = this.getClass().getClassLoader().getResourceAsStream("data/agent.xml") ;
xStream.alias("root", Map.class);
xStream.alias("agent", Agent.class);
xStream.registerConverter(new ResultConverter());
xStream.registerConverter(new AgentConverter());
xStream.ignoreUnknownElements();

Object obj = xStream.fromXML(stream);

I don't understand how to step down in favor of another converter.

public class ResultConverter implements Converter {

...


public Object unmarshal(HierarchicalStreamReader reader,
        UnmarshallingContext context) {
    Map<String, Object> agents = new HashMap<String, Object>();
    while( reader.hasMoreChildren() ) {
        reader.moveDown();
        // HOW I DO TO STEP DOWN IN FAVOR OF Agent CONVERTER ?
        reader.moveUp();
    }
    return agents;
}

I didn't see Xstream scrolled dow the thierarchy to activate my AgentConverter.

I surely missing the point

EDIT

Xstream may be not thr right tool for this. I would use xmlbeam, according to Cfx advise. XMLBeam projects the XML to a Java Class according to XPATH mapping.

Answer 1

Seems that you want the xml structure not to be reflected in your Java class. If you stick to XStream, I have no solution. But there is an alternative framework that was made to solve exactly this issue. It uses annotations, but IMHO does not violate the KISS principle. Here is an example:

public interface Agent {

@XBRead("/root/agent/id")
String getId();

@XBRead("/root/agent/name")
String getName();

@XBRead("/root/agent/forename")
String getForname();

@XBRead("/root/agent/unit/name")
String getUnitName();

@XBRead("/root/agent/unit/legacyStructurBlablabla/type")
String getUnitType();

}

You will define interfaces instead of classes, but the instances of these interfaces are useable just like POJOs. (with toString(), equals(), hashCode,...). Creating instances of these interfaces is like this:

Agent agent = new XBProjector().io().stream(stream).read(Agent.class);