XStream + variable as an attribute to another variable which is tag.

[Jigar Naik]

Hi

I am using XStream API For Object to XML Conversion.

Bellow is my

POJO

public class AlarmFile {
	@XStreamAlias("id")
	@XStreamAsAttribute()
	private String fileName;
	
	@XStreamAlias("text")
	@XStreamAsAttribute()
	private String fileId;
	
	private String userdata;
	
	@XStreamAlias("name")
	private String name;

and i am getting the following output in XML

    <item id="F20090120.xml" text="F20090120.xml">
      <userdata>http://www.google.com/</userdata>
      <name>myurl</name>
    </item>

but i want the <name> as an attribute to <userdata> tag.

like bellow.

    <item id="F20090120.xml" text="F20090120.xml">
      <userdata name="myurl">http://www.google.com/</userdata>
    </item>

can anybody help me out solving it.
I am clueless.

[Omar Al Kababji]

you should add to your xstream instance the following line of code

instance.processAnnotations(POJOClassThatContainsAnnotatins);

[Jigar Naik]

Ya that i tried but then it gave me the bellow output which is logically correct, but I want the name attribute to the <userdata> node.

<item id="F20090120.xml" text="F20090120.xml" name="myurl">   
      <userdata >http://www.google.com/</userdata>   
</item>  

[Omar Al Kababji]

I think that you can't do that

[Jigar Naik]

all right.. Thanks for reply...

[Paul Clapham]

As a guess: you would have to create a UserData class to hold that "name" attribute.

[Omar Al Kababji]

Yes Paul in this case of-course it would work ;)

[Jigar Naik]

Nope, It does not work

Bellow is the output

<item id="F827328323" name="F827328323">
  <userdata>http://www.javaranch.com/</userdata>
  <userdata name="myUrl"/>
</item>

   
...
...
	public static void main(String[] args){
		UserData userdata = new UserData();
		userdata.setName("myUrl");
		
		Item item = new Item();
		item.setId("F827328323");
		item.setName("F827328323");
		item.setUserData("http://www.javaranch.com/");
		
		item.setUserdata(userdata);
		
		XStream xstream = new XStream();
		xstream.autodetectAnnotations(true);
		System.out.println(xstream.toXML(item));
	}
...
...
 

Any :idea: :?:

[Paul Clapham]

You are calling item.setUserData and item.setUserdata??? Besides being confusing to people who might have to maintain your code in the future, that sets two different things.

Besides, you don't even have your data model straight yet. You want your <userdata> element to contain that URL as text and to have a "name" attribute. So the Userdata object ought to contain those data items, no? Why would you put one of them in the Item object and expect it to come out in the <userdata> element?

[Omar Al Kababji]

Yes it works but remove the userData object of type string and if you need some other information encloseit in the UserData object this way it should work, if i didn't understond wrong please providean xml thaylt shows what is exactly your desired output.

[Jigar Naik]

I think either i am too dumb or there is a missudnerstanding..

I am trying to get the following xml

<item id="F20090120.xml" text="F20090120.xml">  
       <userdata name="myurl">http://www.google.com/</userdata>  
</item>

If you dont mind,can you please make changes in my main method which is as bellow

    
...
...
public static void main(String[] args){
		
		UserData userdata = new UserData();
		userdata.setName("myUrl");
		userdata.setUserdata("http://javaranch.com/");
		
		Item item = new Item();
		item.setId("F827328323");
		item.setName("F827328323");
		item.setUserdata(userdata);
		
		item.setUserdata(userdata);
		
		XStream xstream = new XStream();
		xstream.autodetectAnnotations(true);
		System.out.println(xstream.toXML(item));
	}
...
...

@XStreamAlias("item")
public class Item {
	
	@XStreamAsAttribute
	private String id;
	
	@XStreamAsAttribute
	private String name;
	
	@XStreamAlias("userdata")
	private UserData userdata;
	
...
...
...



@XStreamAlias("userdata")
public class UserData {
	@XStreamAsAttribute
	private String name;
	private String userdata;
	

currently giving me following output

    
<item id="F827328323" name="F827328323">
  <userdata name="myUrl">
    <userdata>http://javaranch.com/</userdata>
  </userdata>
</item>

I am still wondering how it is possible. :?

Thanks...

[Omar Al Kababji]

try using this code

public class Test {

	public static void main(String args[]){
		XStream xstream = new XStream();
		xstream.alias("item", Item.class);
		xstream.alias("userdata", UserData.class);
		
		//auto detect annotations
		xstream.autodetectAnnotations(true);

		
		UserData userdata = new UserData();
		userdata.setName("name");
		userdata.setUrl("url");
		
		Item item = new Item();
		item.setId("id");
		item.setText("text");
		item.setUserdata(userdata);
		
		System.out.println(xstream.toXML(item));
		
	}    

@XStreamAlias(value="userdata")
public class UserData {

	@XStreamAsAttribute
	private String name;
	
	private String url;
	
	public UserData() {
		
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}
	
}    

 public class Item {

	@XStreamAsAttribute
	private String id;
	
	@XStreamAsAttribute
	private String text;
	
	private UserData userdata;

	public String getId() {
		return id;
	}

	public void setId(String id) {
		this.id = id;
	}

	public String getText() {
		return text;
	}

	public void setText(String text) {
		this.text = text;
	}

	public UserData getUserdata() {
		return userdata;
	}

	public void setUserdata(UserData userdata) {
		this.userdata = userdata;
	}
}   

[Jigar Naik]

Hi Omar,

Thanks a lot for the code.

I executed the code, and it gave me the bellow output.

   <item id="id" text="text">
  <userdata name="name">
    <url>url</url>
  </userdata>
</item>
 

instead of

<item id="id" text="text">
  <userdata name="name">
    url
  </userdata>
</item>

I think what i want is not posible using XStream.

Anyways... Thanks a lot for your time.
Regards,

[Omar Al Kababji]

Hi again nothing is impossible, you should use a Converter llike this code:

public class UserDataConverter implements Converter{
  public void marshal(Object object, HierarchicalStreamWriter writer, MarshallingContext context){
    UserData userData = (UserData)object;
    writer.addAttribute("name", userData.getName());
    writer.setValue(userData.getUrl());
  }

  public boolean canConvert(Class theClass){
    return theClass.equals(UserData.class);
  }

  //you don't need to implement this method
  public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context){
     return null;
  }
}

and then add this Converter to your xstream instance

xstreamInstance.registerConverter(new UserDataConverter());

[Jigar Naik]

    
<item id="F827328323" name="F827328323">
  <userdata name="myUrl">http://javaranch.com/</userdata>
</item>

Mannn... you did it... you are right.. nothing is impossible... quite motivating reply...

Thanks a lot omar.. .

[Omar Al Kababji]

Welcome any time ;)

[uthaman udayakumar]

Hi Omar,

This converter can be used only for the UserData class, what if i have some more nodes with the same case, do i have to write seperate converters for and every nodes.. or is there any way can we genralize this converter... Please see below for the sample xml for this case...

 <item id="F827328323" name="F827328323">  
   <userdata name="myUrl">http://javaranch.com/</userdata>  
   <usertype name="myType">beginner</userdata>
   ......
   ......
 </item>   

[Omar Al Kababji]

Hi, you should write a converter for each separate class, however if you make both classes extend the same base class, that contains the name attribute, i think that you can avoid writing a converter for each class.

[uthaman udayakumar]

Thanks Omar,

it worked...