Comments for Wet Feet - Online Marketing and Technology Blog

Comment on Goolge app engine + java + spring + REST + JSON + Flex – Part 1 by Duvvur VS

Duvvur VS — Mon, 19 Jul 2010 21:09:44 +0000

I am using following method in Controller
@ModelAttribute(“users”)
@RequestMapping(value = “/GetList.json”, method = RequestMethod.GET)
public @ResponseBody List getList() throws Exception{
List users = new ArrayList();
try {

User user1 = new User();

user1.setFirstName(“Vijayasekhar”);
user1.setLastName(“Duvvur”);
users.add(user1);

User user2 = new User();

user2.setFirstName(“Markus”);
user2.setLastName(“Rogosinsky”);
users.add(user2);

} catch (Exception e) {
return null;
}
System.out.println(“Exit GetList method ” + users);
return users;
}

and i am invoking using RestTemplate as follows

List list = template.getForObject(url, List.class);

When i am trying to print list its collection of LinkedHashMap objects instead of User objects

I am not understanding whats going on ..

Comment on Chain of Title, Title Seasoning and Land Trusts by Robert Tapia

Robert Tapia — Thu, 15 Jul 2010 19:37:40 +0000

Here is another story that explains why the historical chain of title is of utmost importance: http://www.wix.com/iPSSystem/1708_Holguin_St
Exposing this tyope of activity got us sued for all things: Defamation instead of disputing the documents we presented that shows fraud all over the place. When will these people ever learn that a good name does not come from scaring people off with overwhelming claims to stiffle exposure of the truth instead, by simply doing what is right.

Comment on Google App Engine + JAVA + JDO + Inheritance + One-To-Many Relationships by Tomas Mazukna

Tomas Mazukna — Tue, 06 Jul 2010 12:35:57 +0000

Its the same as ModelBase, I just copy-pasted from different Project where it is called EntityBase.

Comment on Google App Engine + JAVA + JDO + Inheritance + One-To-Many Relationships by Prabuddha

Prabuddha — Tue, 06 Jul 2010 11:02:52 +0000

Can you post the EntityBase class. Is it any different from the ModelBase class

Comment on Google App Engine + JAVA + JDO = Simple Search by Tomas Mazukna

Tomas Mazukna — Tue, 22 Jun 2010 12:39:56 +0000

The reason you have to use Key is mandated for the child objects. Key is actually combination of 2 ids: parent and child. You can also use it for parent objects, but I like Long for simplicity. If you try using Long for child key Data Nucleus will complain very loudly

Tomas

Comment on Google App Engine + JAVA + JDO = Simple Search by Col

Col — Tue, 22 Jun 2010 06:58:27 +0000

Hi Tomas,

Thanks for the great posts. I’ve read them all today and have found them extremely helpful.

I just wanted to ask about the Key property. You seem to use it for some primary keys and you use Long for some others. Is there a reason for this?

thanks

Comment on Google App Engine – Full Text Search with JDO – Revisited by Gene

Gene — Thu, 17 Jun 2010 19:06:15 +0000

Ignore me.. it is in the lucene 3.0.2 package under: /lucene-3.0.2/contrib/snowball

Thanks!

Comment on Google App Engine – Full Text Search with JDO – Revisited by Gene

Gene — Thu, 17 Jun 2010 18:53:18 +0000

I like this example. It is obviously very comprehensive and a big help for myself. So thanks for that.

I am have downloaded the lucene package 3.0.2. but I am having trouble download the SnowballAnalyzer code. Could you please supply a location for the jar file?

Comment on Google App Engine + JAVA + JDO + Inheritance + One-To-Many Relationships by Tomas Mazukna

Tomas Mazukna — Fri, 04 Jun 2010 11:34:43 +0000

Bruce,

Your observation is correct – you can not have children of the same class.
My hunch is that it is due to the implementation of the Key class.
Each child Key holds reference to parent key/id. In theory it should be possible to have child of the same type, but I think current implementation does not allow it. Maybe to safeguard for infinite loop where you make same object child and parent……

Tomas

Comment on Google App Engine + JAVA + JDO + Inheritance + One-To-Many Relationships by Bruce

Bruce — Sat, 22 May 2010 02:31:55 +0000

Tomas,

could you help me a bit if you have time?
yesterday I was trying to model a simple forum comments. Just a
comments which you can add more comments to.
So, the approximation of the entity is like this:
——————————————————————-
@PersistenceCapable (detachable = “true”, identityType =
IdentityType.APPLICATION)
public class CommentEntity {

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;

@Persistent
private String category;

@Persistent
private String commentDate;

@Persistent
private String userName;

@Persistent
private String commentBody;

@Persistent
private List children = new
ArrayList();

getters/setters/etc.
}

DataNucleus enhancement goes ok, no errors in the console.
Call of the pm.makePersistent() goes without any exceptions for such
entity.
BUT IT IS NOT PERSISTED.

I found out that problem is in “children” property. And the problem is
it’s a list of objects of the same class as the parent entity. If I
comment that property declaration the entity is persisted. Also if I
change the type of the child entities to some new class (not extending
the CommentEntity) it also gets persisted.

So my suspicion is that JDO (or GAE JDO impl) does not allow child
entities to be of the same class. Is it correct? Maybe I’m missing
something essential? Please advice.