Re: [Simple-support] Serialize and deserialize undefined Xml attributes into a HashMap<String, String>

[Christian K. <c....@sp...>]

Hi Niall,

thanks for your quick response.


Now I have implemented an Visitor.
In the read method, I can get a nodeMap with all xml attributes.

I can also detect via refection which attributes have the annotation 
@Attribute.
All other attributes should be stored in the HashMap "furtherAttributes".

But I don't known how to put them into the HashMap "furtherAttributes".
I do not have the resulting car object. Do you have any tip?

public class AnyAttributesVisitor implements Visitor
{
     @Override
     public void read(Type type, NodeMap<InputNode> nodeMap) throws 
Exception
     {
         // nodeMap contains all xml attributes of the car xml
         // Content is:
         // {color=attribute color='red', length=attribute length='4.3',
         // nrOfDoors=attribute nrOfDoors='4', fuelConsumption=attribute
         // fuelConsumption='7.8', topSpeed=attribute topSpeed='190'}


         //Detect attributes with Annotation @Attribute
         ArrayList<String> attributesWithAnnotation = new 
ArrayList<String>();
         for (Field field : type.getType().getFields())
         {
             if (field.getAnnotation(Attribute.class) != null)
             {
                 String name = field.getAnnotation(Attribute.class).name();

                 if (name == null || name.equals(""))
                 {
                     name = field.getName();
                 }

                 attributesWithAnnotation.add(name);
             }
         }

         for (String entry : nodeMap.getNode().getAttributes())
         {
             if (!attributesWithAnnotation.contains(entry))
             {
                 String furtherAttributeKey = entry;
                 String furtherAttributeValue = nodeMap.getNode()
                         .getAttribute(entry).getValue();

                 // TODO: Add Key and Value to the Hashmap furtherAttributes

                 nodeMap.remove(furtherAttributeKey);
             }
         }
     }

     @Override
     public void write(Type type, NodeMap<OutputNode> nodeMap) throws 
Exception
     {

     }
}

This is my test case:
public void testCarDeserialisation() throws Exception
     {
         String xml = "<Car color=\"red\" length=\"4.3\" nrOfDoors=\"4\" 
fuelConsumption=\"7.8\" topSpeed=\"190\" />";

         Serializer serializer = new Persister(new VisitorStrategy(
                 new AnyAttributesVisitor()));

         Car car = serializer.read(Car.class, xml);
     }

Thanks Christian

Am 15.11.2012 00:33, schrieb Niall Gallagher - Yieldbroker:
> I think a Visitor would be simpler than a Strategy, there are many test cases doing this very thing. Just browse through them, I am sure you will find a template. You can browse them here http://simple.svn.sourceforge.net/viewvc/simple/trunk/download/stream/src/test/java/org/simpleframework/xml/
>
> -----Original Message-----
> From: Christian Klotz [mailto:c....@sp...]
> Sent: Wednesday, 14 November 2012 8:26 PM
> To: sim...@li...
> Subject: [Simple-support] Serialize and deserialize undefined Xml attributes into a HashMap<String, String>
>
> Hi SimpleXml Team,
>
> I use SimpleXml frequently on android and it is great.
>
> Now I have a question how to do that job:
> All XML attributes that are not defined in the Java class with @Attribute should be serialized and deserialized into a HashMap<String,String>.
>
> Here is an example:
>
> This is out test class "Car"
>
> @Root(strict = false, name = "Car")
> public class Car
> {
>       @Attribute
>       public double length;
>
>       @Attribute
>       public String color;
>
>       @Attribute
>       public int nrOfDoors;
>
>       public HashMap<String, String> furtherAttributes = new HashMap<String, String>(); }
>
> And this is the serialization test method:
> public void testCar() throws Exception
>       {
>           Car car = new Car();
>
>           car.color = "red";
>           car.length = 4.3;
>           car.nrOfDoors = 4;
>
>           car.furtherAttributes.put("fuelConsumption", "7.8");
>           car.furtherAttributes.put("topSpeed", "190");
>
>           Serializer serializer = new Persister();
>           StringWriter stringwriter = new StringWriter();
>           serializer.write(car, stringwriter);
>
>           String xml = stringwriter.toString();
>       }
>
>
> The result of the serialization is:
> <Car color="red" length="4.3" nrOfDoors="4"/>
>
> So the furtherAttributes of the HashMap are missing. The result should be:
> <Car color="red" length="4.3" nrOfDoors="4" fuelConsumption="7.8"
> topSpeed="190" />
>
> And the way back should also work:
> So if we have a xml like this:
> <Car color="green" length="3.3" nrOfDoors="2" topSpeed="190" brand="audi" /> After the deserialization the HashMap "furtherAttributes" should have the two undefined attributes "topSpeed" and "brand".
>
> I already read the mailing list and some SimpleXml test cases.
> So I try implement a new Strategy to solve that problem.
>
> The AnyAttributeRegistryStrategy looks for classes with annotation "AnyClass" and inside that class searches for the annotation "Any".
> The annotation "Any" is used to tag the HashMap, where the futher attributes should be serialized to.
>
> public class AnyAttributeRegistryStrategy extends RegistryStrategy {
>       public AnyAttributeRegistryStrategy(Registry registry)
>       {
>           super(registry);
>       }
>
>       @Override
>       public boolean write(Type type, Object value, NodeMap<OutputNode> node,
>               @SuppressWarnings("rawtypes") Map map) throws Exception
>       {
>
>           if (value.getClass().getAnnotation(AnyClass.class) != null)
>           {
>               for (Field field : value.getClass().getFields())
>               {
>                   if (field.getAnnotation(Any.class) != null)
>                   {
>                       Object mapObject = field.get(value);
>                       if (mapObject instanceof Map<?, ?>)
>                       {
>                           Map<?, ?> keyValueMap = (Map<?, ?>) mapObject;
>                           for (Entry<?, ?> keyValuePair :
> keyValueMap.entrySet())
>                           {
>                               if (keyValuePair.getKey() != null
>                                       && keyValuePair.getValue() != null)
>                               {
>                                   node.getNode().setAttribute( keyValuePair.getKey().toString(), keyValuePair.getValue().toString());
>                               }
>                           }
>
>                       }
>                   }
>               }
>           }
>
>           return super.write(type, value, node, map);
>       }
> }
>
> And this is the Car class with the new annotations:
> @AnyClass
> @Root(strict = false, name = "Car")
> public class Car
> {
>       @Attribute
>       public double length;
>
>       @Attribute
>       public String color;
>
>       @Attribute
>       public int nrOfDoors;
>
>       @Any
>       public HashMap<String, String> furtherAttributes = new HashMap<String, String>(); }
>
> Now the serialisation of the class to xml works.
> But I do not have a correctly working solution for the deserialisation.
> Do you have any ideas?
>
> Thanks for you help
>
> Christian Klotz
>
>
>
>
>
>
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-- 
Mit freundlichen Grüßen / Kind regards

Christian Klotz
Software Engineer


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