Exception during JDO getObjectById

[Venki Balakrishnan]

Hello:

I have the following JDO entity class:

@PersistenceCapable(detachable = "false")

public class BizContext implements Serializable{

/**

* 

*/

private static final long serialVersionUID = -3573604788900579800L;

@PrimaryKey

@Persistent

private String contextKey;

@Persistent

private String contextId;

....

.....

I have a logic where I am reading this entity based on the Id. The code snippet is as given below:

...

if (contextKey != null) {

result.setContext(pm.getObjectById(BizContext.class, contextKey));

}

return result;

However when I run this piece of code, I get the following exception:

at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)

Caused by: java.lang.IllegalArgumentException: name cannot be null or empty

at com.google.appengine.api.datastore.KeyFactory.createKey(KeyFactory.java:70)

at com.google.appengine.api.datastore.KeyFactory.createKey(KeyFactory.java:57)

at org.datanucleus.store.appengine.EntityUtils.stringToInternalKey(EntityUtils.java:301)

at org.datanucleus.store.appengine.EntityUtils.idToInternalKey(EntityUtils.java:136)

at org.datanucleus.store.appengine.EntityUtils.idToInternalKey(EntityUtils.java:126)

at org.datanucleus.store.appengine.jdo.DatastoreJDOPersistenceManager.getObjectById(DatastoreJDOPersistenceManager.java:63)

at com.samuuhanet.main.server.service.ContextServiceImpl.getContextDetailsLocal(ContextServiceImpl.java:135)

at com.samuuhanet.main.server.service.ContextServiceImpl.getContextDetails(ContextServiceImpl.java:36)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100)

at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569)

... 34 more

Any ideas as to what could be the cause of this exception ?

Thanks a lot.

[Sébastien Tromp]

How do you create the contextKey? Is this a value you define yourself before persisting the BizContext?

I'm no expert on this, but the documentation specifies two use cases for keys as String:

    @PrimaryKey
    private String name;

    @PrimaryKey
    @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)

    @Extension(vendorName="datanucleus", key="gae.encoded-pk", value="true")

    private String encodedKey;

There is no @Persistant in the first case. Maybe this has something to do with your issue?

Cheers, 

-- 

Sébastien Tromp

2011/7/30 venkyvb <ven...@gmail.com>

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[Bevis]

Dears,

 Please try to replace your code with following code and try.

    @PrimaryKey

@Persistent

private Key contextKey;

 And persist your object to store by following way.

  

        (User is an Pojo in my application)

    Key key=KeyFactory.createKey(User.class.getSimpleName(), user.getUid());

user.setKey(key);  // you should provide a set mothod to set the Key to your filed.

pm.makePersistent(user);

Bevis.