Based on GAE JDO page (http://code.google.com/appengine/docs/java/datastore/jdo/relationships.html), I create Employee and ContactInfo objects with relation one to many.

public class Employee implements Serializable{
@Persistent(mappedBy = “employee”, defaultFetchGroup = “true”)
@Element(dependent = “true”)
private List contactInfoSets;
…

public class ContactInfo implements Serializable{
@Persistent
private String streetAddress;
…

I try to exec below code always give me error (java.lang.AssertionError: expected: but was:) because but the return value is 0.

String statement = “SELECT FROM ” + Employee.class.getName()
+ ” WHERE contactInfoSets.contains(i) && i.streetAddress==’myaddress’”
+ ” VARIABLES ” + ContactInfo.class.getName() + ” i “;
javax.jdo.Query query = pm.newQuery(statement);
List companyProfiles = (List) query.execute();

Thanks…

Here the code

**[Employee.java]**

import java.io.Serializable;
import java.util.List;

import javax.jdo.annotations.IdGeneratorStrategy;
import javax.jdo.annotations.IdentityType;
import javax.jdo.annotations.PersistenceCapable;
import javax.jdo.annotations.Persistent;
import javax.jdo.annotations.PrimaryKey;
import javax.jdo.annotations.Element;

import com.google.appengine.api.datastore.Key;

@SuppressWarnings(“serial”)
@PersistenceCapable(identityType = IdentityType.APPLICATION, detachable = “true”)
public class Employee implements Serializable{

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

@Persistent(mappedBy = “employee”, defaultFetchGroup = “true”)
@Element(dependent = “true”)
private List contactInfoSets;

public List getContactInfoSets() {
return contactInfoSets;
}
public void setContactInfoSets(List contactInfoSets) {
this.contactInfoSets = contactInfoSets;
}
public Key getKey() {
return key;
}
public void setKey(Key key) {
this.key = key;
}
}

**[ContactInfo.java]**

import java.io.Serializable;

import javax.jdo.annotations.IdGeneratorStrategy;
import javax.jdo.annotations.IdentityType;
import javax.jdo.annotations.PersistenceCapable;
import javax.jdo.annotations.Persistent;
import javax.jdo.annotations.PrimaryKey;

import com.google.appengine.api.datastore.Key;

@SuppressWarnings(“serial”)
@PersistenceCapable(identityType = IdentityType.APPLICATION, detachable = “true”)
public class ContactInfo implements Serializable{

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

@Persistent
private String streetAddress;

@Persistent
private Employee employee;

public Key getKey() {
return key;
}

public void setKey(Key key) {
this.key = key;
}

public String getStreetAddress() {
return streetAddress;
}

public void setStreetAddress(String streetAddress) {
this.streetAddress = streetAddress;
}

public Employee getEmployee() {
return employee;
}

public void setEmployee(Employee employee) {
this.employee = employee;
}
}

**[TestJdoCollection.java]**

import static com.google.appengine.api.datastore.FetchOptions.Builder.withLimit;
import static org.junit.Assert.assertEquals;

import java.util.ArrayList;
import java.util.List;

import javax.jdo.PersistenceManager;
import javax.jdo.PersistenceManagerFactory;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.cea.common.service.CeaServiceFactory;
import com.cea.common.service.PersistenceService;
import com.google.appengine.api.datastore.DatastoreService;
import com.google.appengine.api.datastore.DatastoreServiceFactory;
import com.google.appengine.api.datastore.Query;
import com.google.appengine.tools.development.testing.LocalDatastoreServiceTestConfig;
import com.google.appengine.tools.development.testing.LocalServiceTestHelper;

public class TestJdoCollection {
private final LocalServiceTestHelper helper = new LocalServiceTestHelper(
new LocalDatastoreServiceTestConfig());

private DatastoreService ds = DatastoreServiceFactory.getDatastoreService();

@Before
public void setUp() {
helper.setUp();
}

@After
public void tearDown() {
helper.tearDown();
}

@Test
public void test(){
CeaServiceFactory ceaServiceFactory = CeaServiceFactory.getInstance();
PersistenceService servicePersistance = (PersistenceService) ceaServiceFactory.getCeaService(CeaServiceFactory.SERVICE_PERSISTANCE);
PersistenceManagerFactory pmf = servicePersistance.getPersistenceManagerFactory();
PersistenceManager pm = pmf.getPersistenceManager();

ContactInfo contactInfo = new ContactInfo();
contactInfo.setStreetAddress(“myaddress”);

Employee employee = new Employee();
List contactInfoSets = new ArrayList();
contactInfoSets.add(contactInfo);
employee.setContactInfoSets(contactInfoSets);

pm.makePersistent(employee);

assertEquals(1, ds.prepare(new Query(“Employee”)).countEntities(withLimit(10)));
assertEquals(1, ds.prepare(new Query(“ContactInfo”)).countEntities(withLimit(10)));

String statement = “SELECT FROM ” + Employee.class.getName() + ” WHERE contactInfoSets.contains(i) && i.streetAddress==’myaddress’”
+ ” VARIABLES ” + ContactInfo.class.getName() + ” i “;
javax.jdo.Query query = pm.newQuery(statement);
List companyProfiles = (List) query.execute();
assertEquals(1, companyProfiles.size());

}
}

I’m struggling with a strange problem with JDO.
I’ve got two PersistenCapable classes, one having a Collection of
objects of the second, something like this:

class First {
@Persistent
@PrimaryKey
Long id;

@Persistent(mappedby=”owner”)
ArrayList list = new ArrayList();

ArrayList getList() {
if (list == null)
list=new ArrayList();
return list;
}

…
}

class Second {
@Persistent
@PrimaryKey
Key id;

@Persistent
First owner;

First getOwner() {
if (owner==null)
owner = new First();
return owner;

…
}

Seems to be quite the same as you example, right?

In another class I need to print the owner of all my First objects, so
I do:
First obj = …;
ArrayList list = obj.getList();
for (Second s : list) {
System.out.println(s.getOwner());
}

In this loop, I find some Second object having null owner, and I
cannot understand why.
Now I have several questions about my data modelling:
1) Do I need to mark any field with (defaultFetchGroup = “true”)
annotation?
2) Does the check on null object (e.g. if (owner==null) owner = new
First();) in the getter methods results in any strange behavior?
3) Does the assignment on definition of objects (e.g.
ArrayList list = new ArrayList();) results in any
strange behavior?
4) Do I need to add any other annotation to owner field of Second
class?

Thank you very much for your help!!
Best regards
cghersi