date:20100208

Hey all,

Since Ikai's post on January 22nd, I haven't had much trouble with my
instance rebooting unexpectedly.  However, today the problem has
returned.  I'm getting instance restarts within a minute or two of
each other on a somewhat regular basis - sometimes even within a few
seconds of each other, caused by my first request.

Jake

On Jan 30, 3:06 pm, Edwin Hautus ehau...@gmail.com wrote:
 I am having this problem for the last week or two after months of good
 performance and very little recycling.
 As my app start up time is around 15 seconds this is really hitting my
 user experience in a negative way.

 On Jan 16, 12:32 am, Ikai Lan i...@google.com wrote:

  Hey everybody,

  We've been seeing more and more reports of applications being cycled out
  overly aggressively, resulting in some folks implementing (discouraged)
  workarounds to keep their application from being cycled out.

  - What is your application ID?

 salsa-amsterdam

  - How do you know it is being cycled out? You'll need to insert some code
  that only gets called when the app cold starts.

 I have some logging which is executed on startup

  - How much time of inactivity does it take before your application is cycled
  out?

 Can be as little as a minute.

  - What time or days does this seem to happen?

 Seems to happen all the time.

  - What frameworks or libraries are you loading?

 Just the plain Servlet API and Groovy.

  Any other information you can provide would be helpful.

 Start up time of the app is about 10 seconds and involves some on the
 fly compilation of Groovy scripts.

  Ikai Lan
  Developer Programs Engineer, Google App Engine

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[appengine-java] What is Specs Features supported by GAE for Java?

2010-02-08 Thread Amr

I need a brief  listed answer in a professional manner for subject
question (As an example, pls see listing under point entitled Java EE
5 platform support that lists GlassFish Specs under this link:
http://docs.sun.com/app/docs/doc/821-0188/gidij?l=ena=view).

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[appengine-java] Dynamic properties (Expando model) possible with Java?

2010-02-08 Thread Johann C. Rocholl

I have been searching through the JDO and JPA docs, but I can't find
info about adding and removing properties at runtime.

The Python interface has the Expando model for this:
http://code.google.com/appengine/docs/python/datastore/expandoclass.html

If I want to read and write my Expando models from Java, do I need to
use the low-level datastore API rather than JDO or JPA?

Thanks,
Johann

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[appengine-java] Getting the client's timezone

2010-02-08 Thread hsjawanda

Hi,

Any ideas on how to get the user's timezone (i.e., the timezone the
client is working in)?

The closest I've come so far to an answer is:
http://j2eecookbook.blogspot.com/2007/06/formatting-date-to-client-timezone.html

Does anybody have a better way of accomplishing this?

I'd prefer to avoid asking the client to set their timezone as a
preference because:

* Sign-ups should be as fast as possible.

* What if the client is temporarily working from a different timezone?

Regards,
Harshdeep

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[appengine-java] JDO Inheritance and new table strategy

2010-02-08 Thread vtellier

Hello everybody !

I am using appengine for a personal project in order to create a
professional application. I find Appengine really powerful but i do
not understand why the new table inheritance strategy is not available
even if it would not be really efficient.
In the documentation it is said that the new table strategy may cause
efficiency troubles due to the non supported join queries. But in
concrete development if we need to store an inherited object using
multiple tables due to the hierarchy and the sense of the application,
we have to add a tier in the code to emulate the inheritance.
I explain myself :
I've got a server data hierarchy in a package called models that is
synchronized with the client data hierarchy. Because of the non
supported new-table strategy I had to create a tier in a package
entities where I implemented all my persistable entities without
inheritance. When an operation needs to access the stored datas, the
models objects play with the entities to retrieve the needed datas and
reassemble them so that the client app can ignore this kind of
operation and have its development perennial.

I assume that it is really not beautiful but I still not understand
why the new-table is not available even if it would require a remote
procedure call for each level of inheritance, because in the hand
this is what we have to do when we are needing the new-table strategy,
and in the other hand it could be a temporary implementation while
waiting for the join queries.

Thanks for answers !

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[appengine-java] Persistence with JPA + GAE

2010-02-08 Thread chevelle

Hi
I am new in the list, in these days i am trying save data between two
entity beans using JPA but without success, i am cheking the log nd
says:

Uncaught exception from servlet
javax.persistence.PersistenceException: Error in meta-data for
beans.distritos.id: Cannot have a java.lang.Long primary key and be a
child object (owning field is beans.evento.distrito).



this is my servlet:
Long id =
Long.parseLong(request.getParameter(idDistrito));
response.setContentType(text/html);
EntityManager cn = emf.get().createEntityManager();

Query q = cn.createQuery(SELECT d FROM distritos d WHERE
d.id = :codigo);
q.setParameter(codigo,id);
distritos dist = (distritos) q.getSingleResult();

EntityManager cn2 = emf.get().createEntityManager();
cn2.getTransaction().begin();

evento e = new evento();
e.setDistrito(dist);
Date fecha = new Date();
e.setFechaCreacion(fecha);

try{
cn2.persist(e);
response.getWriter().write(ok);
}finally{
cn2.getTransaction().commit();
cn2.close();
}


this is my entity bean

Evento:
@Entity
public class evento implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
Long id;

@Temporal(javax.persistence.TemporalType.DATE)
private Date fechaCreacion;

@JoinColumn
@OneToMany(cascade = CascadeType.ALL)
private distritos distrito;

   --getter and setter--



Distrito:
@Entity
public class distritos implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
Long id;
private String distrito;

--getter and setter--


i hope anyone help me, Thank!



Johan

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[appengine-java] Close PersistenceManager every time?

2010-02-08 Thread hsjawanda

Should the PersistenceManager be closed after every query?

I have a utility class that handles querying the datastore. This class
then returns results which are used by JSP pages to show output.

AFAIK, these are my options:

* Make all my data objects detachable (what is the extra cost of doing
this? Don't they have to be copied when detaching?
)
* Make a second call on the utility class to close the PM (defeats the
purpose of having the utility class)

* Leave my PM unclosed (what is/are the implications of this?)

I am referring to a case where I am only doing reads from the data
store.

Regards,
Harshdeep

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[appengine-java] persistence with JPA





Hi
I am new in the list, in these days i am trying save data between two
entity beans using JPA but without success, i am cheking the log nd
says:

Uncaught exception from servlet
javax.persistence.PersistenceException: Error in meta-data for beans.distritos.id: Cannot have a java.lang.Long primary key and be a child object (owning field is beans.evento.distrito).


this is my servlet:
 Long id =
Long.parseLong(request.getParameter("idDistrito"));
 response.setContentType("text/html");
 EntityManager cn = emf.get().createEntityManager();

 Query q = cn.createQuery("SELECT d FROM distritos d WHERE
d.id = :codigo");
 q.setParameter("codigo",id);
 distritos dist = (distritos) q.getSingleResult();

 EntityManager cn2 = emf.get().createEntityManager();
   cn2.getTransaction().begin();

 evento e = new evento(); 
 e.setDistrito(dist);
 Date fecha = new Date();
 e.setFechaCreacion(fecha);

 try{
 cn2.persist(e);
 response.getWriter().write("ok");
 }finally{
 cn2.getTransaction().commit();
 cn2.close();
 }


this is my entity bean

Evento:
@Entity
public class evento implements Serializable {
 @Id
 @GeneratedValue(strategy = GenerationType.IDENTITY)
 Long id;

 @Temporal(javax.persistence.TemporalType.DATE)
 private Date fechaCreacion;

 @JoinColumn
 @OneToMany(cascade = CascadeType.ALL)
 private distritos distrito;

 --getter and setter--



Distrito:
@Entity
public class distritos implements Serializable {
 @Id
 @GeneratedValue(strategy = GenerationType.IDENTITY)
 Long id;
 private String distrito;
 
 --getter and setter--


i hope anyone help me, Thank!





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[appengine-java] Persistence in JPA





Hi
I am new in the list, in these days i am trying save data between two
entity beans using JPA but without success, i am cheking the log nd
says:


Uncaught exception from servlet
javax.persistence.PersistenceException: Error in meta-data for beans.distritos.id: Cannot have a java.lang.Long primary key and be a child object (owning field is beans.evento.distrito).


this is my servlet:
 Long id =
Long.parseLong(request.getParameter("idDistrito"));
 response.setContentType("text/html");
 EntityManager cn = emf.get().createEntityManager();

 Query q = cn.createQuery("SELECT d FROM distritos d WHERE
d.id = :codigo");
 q.setParameter("codigo",id);
 distritos dist = (distritos) q.getSingleResult();

 EntityManager cn2 = emf.get().createEntityManager();
   cn2.getTransaction().begin();

 evento e = new evento(); 
 e.setDistrito(dist);
 Date fecha = new Date();
 e.setFechaCreacion(fecha);

 try{
 cn2.persist(e);
 response.getWriter().write("ok");
 }finally{
 cn2.getTransaction().commit();
 cn2.close();
 }


this is my entity bean

Evento:
@Entity
public class evento implements Serializable {
 @Id
 @GeneratedValue(strategy = GenerationType.IDENTITY)
 Long id;

 @Temporal(javax.persistence.TemporalType.DATE)
 private Date fechaCreacion;

 @JoinColumn
 @OneToMany(cascade = CascadeType.ALL)
 private distritos distrito;

 --getter and setter--



Distrito:
@Entity
public class distritos implements Serializable {
 @Id
 @GeneratedValue(strategy = GenerationType.IDENTITY)
 Long id;
 private String distrito;
 
 --getter and setter--


i hope anyone help me, Thank!
 

-- 
Atentamente,
Johan Vallejo Elias
Soluflex ERP
Nextel  : 827*239
Celular : 998270239
Oficina : 434-2649 anexo 102
Skype : soporte_soluflex
Web : www.guiadecalles.pe
Blog 1 : www.vnperu.com/blog
Blog 2 : www.rfid.com.pe








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[appengine-java] JDO model issue

2010-02-08 Thread Rodolphe

Hello,

I am very new to appengine, and I am trying a very basic model exemple: A
Race class is linked to a Runner class through a Result class

When I am running the folloging code (the full code is attached):
Race race = new Race(Paris, new Date(), 10);

Runner runner1 = new Runner(Smith);
Runner runner2 = new Runner(John);

Result result1 = new Result(race, runner1, 1);
Result result2 = new Result(race, runner2, 2);

PersistenceManager pm = PMF.get().getPersistenceManager();
try {
race = pm.makePersistent(race);

runner1 = pm.makePersistent(runner1);
runner2 = pm.makePersistent(runner2);

pm.makePersistent(result1);
pm.makePersistent(result2);
} finally {
pm.close();
}

I get the following error:
Detected attempt to establish Result(4) as the parent of Runner(2) but the
entity identified by Runner(2) has already been persisted without a parent.
A parent cannot be established or changed once an object has been persisted.
org.datanucleus.store.appengine.FatalNucleusUserException: Detected attempt
to establish Result(4) as the parent of Runner(2) but the entity identified
by Runner(2) has already been persisted without a parent.  A parent cannot
be established or changed once an object has been persisted.
at
org.datanucleus.store.appengine.DatastoreRelationFieldManager.checkForParentSwitch(DatastoreRelationFieldManager.java:204)
at
org.datanucleus.store.appengine.DatastoreRelationFieldManager$1.setObjectViaMapping(DatastoreRelationFieldManager.java:125)
at
org.datanucleus.store.appengine.DatastoreRelationFieldManager$1.apply(DatastoreRelationFieldManager.java:104)
at
org.datanucleus.store.appengine.DatastoreRelationFieldManager.storeRelations(DatastoreRelationFieldManager.java:78)
at
org.datanucleus.store.appengine.DatastoreFieldManager.storeRelations(DatastoreFieldManager.java:812)
at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertPostProcess(DatastorePersistenceHandler.java:288)
at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObjects(DatastorePersistenceHandler.java:241)
at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObject(DatastorePersistenceHandler.java:225)
at
org.datanucleus.state.JDOStateManagerImpl.internalMakePersistent(JDOStateManagerImpl.java:3185)
at
org.datanucleus.state.JDOStateManagerImpl.makePersistent(JDOStateManagerImpl.java:3161)
at
org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:1298)
at
org.datanucleus.ObjectManagerImpl.persistObject(ObjectManagerImpl.java:1175)
at
org.datanucleus.jdo.JDOPersistenceManager.jdoMakePersistent(JDOPersistenceManager.java:669)
at
org.datanucleus.jdo.JDOPersistenceManager.makePersistent(JDOPersistenceManager.java:694)
at race.TestRace.test2(TestRace.java:58)

Any idea how I could solve this ?

Thank you in advance
Rodolphe

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TestRace.java
Description: Binary data


Race.java
Description: Binary data


Result.java
Description: Binary data


Runner.java
Description: Binary data

[appengine-java] Google App Engine for Java: Specs is needed

2010-02-08 Thread Amr Darwish

Hi All, I am now trying to take an architrecture descision to go for Google
App Engine for Java or not but I did not find a topic that gathers all
Specs regarding it in one place. What I am looking for is the usual Standard
Server Application Server Arch. Specs like JSF, EJB  JPA support for
instance. Anyone can help?

Google App Engine Team, The more formal  professional announcement reg.
your work would be greatly appreciated by IT community. Pls help.

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[appengine-java] Generic type in GAE JDO. Howto?

2010-02-08 Thread Alex Lui

As java.util.Map isn't supported by GAE, I'm trying to create a class

@PersistenceCapable(identityType = IdentityType.APPLICATION,
detachable=true)
public class DAOMapK extends Object, V extends Object implements
MapK,V {
...

however, got such exception in Eclipse console

DataNucleus Enhancer (version 1.1.4) : Enhancement of classes
Errors were encountered when loading the specified MetaData files and
classes. See the nested exceptions for details
DataNucleus Enhancer completed with an error. Please review the
enhancer log for full details. Some classes may have been enhanced but
some caused errors
Feb 8, 2010 2:55:53 PM org.datanucleus.enhancer.DataNucleusEnhancer
main
SEVERE: DataNucleus Enhancer completed with an error. Please review
the enhancer log for full details. Some classes may have been enhanced
but some caused errors
Errors were encountered when loading the specified MetaData files and
classes. See the nested exceptions for details
org.datanucleus.exceptions.NucleusUserException: Errors were
encountered when loading the specified MetaData files and classes. See
the nested exceptions for details
at
org.datanucleus.metadata.MetaDataManager.loadClasses(MetaDataManager.java:
426)
at
org.datanucleus.enhancer.DataNucleusEnhancer.getFileMetadataForInput(DataNucleusEnhancer.java:
743)
at
org.datanucleus.enhancer.DataNucleusEnhancer.enhance(DataNucleusEnhancer.java:
545)
at
org.datanucleus.enhancer.DataNucleusEnhancer.main(DataNucleusEnhancer.java:
1252)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:
39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:
25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.google.appengine.tools.enhancer.Enhancer.execute(Enhancer.java:
57)
at com.google.appengine.tools.enhancer.Enhance.init(Enhance.java:
60)
at com.google.appengine.tools.enhancer.Enhance.main(Enhance.java:41)
Caused by: java.lang.IllegalStateException: Unknown type: K
at
org.datanucleus.jdo.metadata.JDOAnnotationReader.processMemberAnnotations(JDOAnnotationReader.java:
1748)
at
org.datanucleus.metadata.annotations.AbstractAnnotationReader.getMetaDataForClass(AbstractAnnotationReader.java:
169)
at
org.datanucleus.metadata.annotations.AnnotationManagerImpl.getMetaDataForClass(AnnotationManagerImpl.java:
136)
at
org.datanucleus.metadata.MetaDataManager.loadAnnotationsForClass(MetaDataManager.java:
2278)
at
org.datanucleus.metadata.MetaDataManager.loadClasses(MetaDataManager.java:
385)
... 10 more
Nested Throwables StackTrace:
java.lang.IllegalStateException: Unknown type: K
at
org.datanucleus.jdo.metadata.JDOAnnotationReader.processMemberAnnotations(JDOAnnotationReader.java:
1748)
at
org.datanucleus.metadata.annotations.AbstractAnnotationReader.getMetaDataForClass(AbstractAnnotationReader.java:
169)
at
org.datanucleus.metadata.annotations.AnnotationManagerImpl.getMetaDataForClass(AnnotationManagerImpl.java:
136)
at
org.datanucleus.metadata.MetaDataManager.loadAnnotationsForClass(MetaDataManager.java:
2278)
at
org.datanucleus.metadata.MetaDataManager.loadClasses(MetaDataManager.java:
385)
at
org.datanucleus.enhancer.DataNucleusEnhancer.getFileMetadataForInput(DataNucleusEnhancer.java:
743)
at
org.datanucleus.enhancer.DataNucleusEnhancer.enhance(DataNucleusEnhancer.java:
545)
at
org.datanucleus.enhancer.DataNucleusEnhancer.main(DataNucleusEnhancer.java:
1252)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:
39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:
25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.google.appengine.tools.enhancer.Enhancer.execute(Enhancer.java:
57)
at com.google.appengine.tools.enhancer.Enhance.init(Enhance.java:
60)
at com.google.appengine.tools.enhancer.Enhance.main(Enhance.java:41)
DataNucleus Enhancer completed and no classes were enhanced. Consult
the log for full details


Any idea?

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[appengine-java] Getting Started : Eclipse, GWT, App Engine - Unable to resolve

2010-02-08 Thread watch

What is need to get  Eclipse to compile AppEngine functions:

import com.google.appengine.api.users.User;
-- Unable to resolve - source code unavailable.

One suggestion was to create a super class to fool the GWT compiler
but that only gets you so far.

I have even gone back to basic and worked through the turorial
http://code.google.com/webtoolkit/doc/latest/tutorial/appengine.html
but the same things happens:

ERROR] StockWatcher/src/com/google/gwt/sample/stockwatcher/client/
StockWatcher.java'
[ERROR] Line 36: UserService cannot be resolved to a type
[ERROR] Line 36: No source code is available for type UserService; did
you forget to inherit a required module?
[ERROR] Line 36: UserServiceFactory cannot be resolved

I know this is a common problem, since there is plenty of refreances
to it, but no soloution.  This is particularly fustrating as it fails
on a basic tutorial.

Any Help?

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[appengine-java] Error while uploading the App - Unable to update

2010-02-08 Thread mike22153

Hi,

I just tried to upload my first App to the Google App Engine. I tried
the Eclipse Plugin and appengine-java-sdk-1.3.0/bin/appcfg.sh.
I have Suse Linux 10.3 and jdk1.6.0_18 installed.

Each time I tried, I got the following error:

--
Reading application configuration data...
Beginning server interaction for ...
0% Creating staging directory
5% Scanning for jsp files.
20% Scanning files on local disk.
25% Initiating update.
Email: ...@xxx.xx
Password for ...@xxx.xx:

java.net.SocketException: java.security.NoSuchAlgorithmException:
Error constructing implementation (algorithm: Default, provider:
SunJSSE, class: sun.security.ssl.DefaultSSLContextImpl)
Unable to update app: java.security.NoSuchAlgorithmException: Error
constructing implementation (algorithm: Default, provider: SunJSSE,
class: sun.security.ssl.DefaultSSLContextImpl)
Please see the logs [/tmp/appcfg55133.log] for further information.

Has anybody an idea? On my pc, the App is running.

Best regards,
Michael

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[appengine-java] cloud based teaching system

2010-02-08 Thread Jeevan

Hi,
am jeevan dongre.I am final year engineering student from computer
science and engineering.
I am doing a project on cloud computing called cloud based teaching
system using google app engine. Iam utilizing google resources like
blog,group,docs and also gmail.Since i am new to this programming
environment i need more information about how java application is
developed and deployed on GAE,what are concepts we need to be aware of
before we start developing the application.
I am collabrating blogs,groups,gmail,channels and docs all together.I
dont know how to make use of the google api's.
so help me in this regard

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Re: [appengine-java] DELETE HTTP Method not working on Google Chrome


Francisco send your code for help you

El 08/02/2010 10:55 a.m., Francisco Gonzalez escribió:

Hi.

I'm developing an application that receives AJAX requests to perform 
some actions. I'm using jQuery to send the requests from the client.


One of those requests is of type HTTP DELETE.

The problem is that this request does not work when using Google 
Chrome on the deployed app. It gets a 400 error (bad request) as 
response.


It works fine on my local SDK though. Firefox works well on both SDK 
and the deployed app.


Anyone having the same trouble? Any ideas?

Thank you in advance!
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Re: [appengine-java] Re: App Engine cold starts and overly aggressive cycling

Thanks for the info, Jake. Has anyone else experienced this? That is, has
anyone else noticed improvement which has since degraded?

On Mon, Feb 8, 2010 at 9:10 AM, Jake jbrooko...@cast.org wrote:

Hey all,

Since Ikai's post on January 22nd, I haven't had much trouble with my
instance rebooting unexpectedly. However, today the problem has
returned. I'm getting instance restarts within a minute or two of
each other on a somewhat regular basis - sometimes even within a few
seconds of each other, caused by my first request.

Jake

On Jan 30, 3:06 pm, Edwin Hautus ehau...@gmail.com wrote:
I am having this problem for the last week or two after months of good
performance and very little recycling.
As my app start up time is around 15 seconds this is really hitting my
user experience in a negative way.

On Jan 16, 12:32 am, Ikai Lan i...@google.com wrote:

Hey everybody,

We've been seeing more and more reports of applications being cycled
out
overly aggressively, resulting in some folks implementing (discouraged)
workarounds to keep their application from being cycled out.

- What is your application ID?

salsa-amsterdam

- How do you know it is being cycled out? You'll need to insert some
code
that only gets called when the app cold starts.

I have some logging which is executed on startup

- How much time of inactivity does it take before your application is
cycled
out?

Can be as little as a minute.

- What time or days does this seem to happen?

Seems to happen all the time.

- What frameworks or libraries are you loading?

Just the plain Servlet API and Groovy.

Any other information you can provide would be helpful.

Start up time of the app is about 10 seconds and involves some on the
fly compilation of Groovy scripts.

Ikai Lan
Developer Programs Engineer, Google App Engine

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[appengine-java] Re: JDO model issue

Hey,

Relationships in GAE are a bit picky.  It is my understanding that you
can only persist children by way of persisting their parents.  So, in
your case, both Race and Runner are children of Result and you would
only persist the two result objects - the dependent children would be
persisted automatically.  I'm willing to bet, though, that a single
race object cannot be the child of two different parent objects,
though I'm not certain.  The details are all here:
http://code.google.com/appengine/docs/java/datastore/relationships.html

For the most part, I've found that parent/child relationships are only
useful when the two are highly related - usually when I'm extending a
class to provide more data.  (e.g. Race - RaceDetails).

The easy way to get around this is to store the objects in unowned
relationships, referencing other objects by IDs as described in
http://code.google.com/appengine/docs/java/datastore/relationships.html#Unowned_Relationships.
Then, with some fancy getters/setters that automatically query the
Datastore, you end up with the same result.  See my example below.

If anyone has any other advice, though, please contribute.  I haven't
found a great way to handle this and I'm trying to avoid using GAE
specific libraries to help.

Jake

public class Race {

   private Key id;
   ...
}

public class Result {

   private Key id;
   private Key raceId;

   public Race getRace() {
   //query datastore with getObjectById(Race.class, raceId);
   }
}

On Feb 6, 7:15 pm, Rodolphe rde...@gmail.com wrote:
 Hello,

 I am very new to appengine, and I am trying a very basic model exemple: A
 Race class is linked to a Runner class through a Result class

 When I am running the folloging code (the full code is attached):
         Race race = new Race(Paris, new Date(), 10);

         Runner runner1 = new Runner(Smith);
         Runner runner2 = new Runner(John);

         Result result1 = new Result(race, runner1, 1);
         Result result2 = new Result(race, runner2, 2);

         PersistenceManager pm = PMF.get().getPersistenceManager();
         try {
             race = pm.makePersistent(race);

             runner1 = pm.makePersistent(runner1);
             runner2 = pm.makePersistent(runner2);

             pm.makePersistent(result1);
             pm.makePersistent(result2);
         } finally {
             pm.close();
         }

 I get the following error:
 Detected attempt to establish Result(4) as the parent of Runner(2) but the
 entity identified by Runner(2) has already been persisted without a parent.
 A parent cannot be established or changed once an object has been persisted.
 org.datanucleus.store.appengine.FatalNucleusUserException: Detected attempt
 to establish Result(4) as the parent of Runner(2) but the entity identified
 by Runner(2) has already been persisted without a parent.  A parent cannot
 be established or changed once an object has been persisted.
     at
 org.datanucleus.store.appengine.DatastoreRelationFieldManager.checkForParentSwitch(DatastoreRelationFieldManager.java:204)
     at
 org.datanucleus.store.appengine.DatastoreRelationFieldManager$1.setObjectViaMapping(DatastoreRelationFieldManager.java:125)
     at
 org.datanucleus.store.appengine.DatastoreRelationFieldManager$1.apply(DatastoreRelationFieldManager.java:104)
     at
 org.datanucleus.store.appengine.DatastoreRelationFieldManager.storeRelations(DatastoreRelationFieldManager.java:78)
     at
 org.datanucleus.store.appengine.DatastoreFieldManager.storeRelations(DatastoreFieldManager.java:812)
     at
 org.datanucleus.store.appengine.DatastorePersistenceHandler.insertPostProcess(DatastorePersistenceHandler.java:288)
     at
 org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObjects(DatastorePersistenceHandler.java:241)
     at
 org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObject(DatastorePersistenceHandler.java:225)
     at
 org.datanucleus.state.JDOStateManagerImpl.internalMakePersistent(JDOStateManagerImpl.java:3185)
     at
 org.datanucleus.state.JDOStateManagerImpl.makePersistent(JDOStateManagerImpl.java:3161)
     at
 org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:1298)
     at
 org.datanucleus.ObjectManagerImpl.persistObject(ObjectManagerImpl.java:1175)
     at
 org.datanucleus.jdo.JDOPersistenceManager.jdoMakePersistent(JDOPersistenceManager.java:669)
     at
 org.datanucleus.jdo.JDOPersistenceManager.makePersistent(JDOPersistenceManager.java:694)
     at race.TestRace.test2(TestRace.java:58)

 Any idea how I could solve this ?

 Thank you in advance
 Rodolphe

  TestRace.java
 3KViewDownload

  Race.java
 1KViewDownload

  Result.java
 1KViewDownload

  Runner.java
 1KViewDownload

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[appengine-java] Question on request duration / quota / HardDeadlineExceededError

2010-02-08 Thread Moritz

Hello everyone,

in my application I have a scheduled task that runs every 5 minutes to
update the cache. Currently it is a brute force implementation, that
runs through all entities and computes all permutations required.

This task usually takes longer than 30 seconds - and fails almost
every time with a HardDeadlineExceededError.

My problem is, that all available information currently is not clear
about how to handle these errors. Maybe I missed it, but:

- The documentation is only about bandwidth, number of requests, API
calls etc.
- The API provides methods to measure number of CPU cycles
(getCpuTimeInMegaCycles()), but doesn't warn about reaching the limit
- In the discussion group I find some information such as maximum
duration of 30 seconds for each request, but that is actually quite
unspecific.
- HardDeadlineExceededError is not documented in the API docs.
Somewhere I read that a DeadlineExceededException should be thrown
before - but I catch any Exception and still produce a
HardDeadlineExceededError

Of course, I could now just use a timer to run my job and terminate it
gracefully shortly before 30 seconds are reached. But I'd prefer a
better, more predictable and reliable option. Any suggestions?

Thanx,
Moritz

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[appengine-java] Re: Google Plugin for Eclipse 1.3 plans

I'm hoping for a good way to resolve workspace dependencies in
Eclipse.  The m2eclipse plugin does this well, but that doesn't play
nicely with the maven-war-plugin, so it doesn't work for GAE.  Running
a Maven Install on each workspace dependency before deploying,
however, is still nicer than having to manually generate/copy jar
files.  I'm pretty new to Eclipse/Maven/GAE, so I don't know if it's
possible, but I'm hopeful! :)

Jake

On Feb 6, 12:40 pm, 杨浩 skzr@gmail.com wrote:
 Where's the lastest plugin update sites for GAE Plugin?
 I will to test it!

 2010/2/6 Philippe Marschall philippe.marsch...@gmail.com

  Sounds like a good start. Ideally the maven eclipse plugin [1] could
  be configured to automatically generate the configuration for the
  Google Plugin and M2Eclipse [2] picking that up as well. Also an
  archetype would help quick starting. I assume you're aware that you
  get the most benefit out of that only when there are up to date Maven
  artifacts wit good metadata in a publicly available repo, preferably
  Maven central.

   [1]http://maven.apache.org/eclipse-plugin.html
   [2]http://m2eclipse.sonatype.org/

  Cheers
  Philippe

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Re: [appengine-java] Question on request duration / quota / HardDeadlineExceededError

2010-02-08 Thread Don Schwarz

You should be able to catch a DeadlineExceededException and have
~400ms in which to return from your request before a
HardDeadlineExceededError is thrown.

Are you sure that you are not catching and ignoring the
DeadlineExceededException?  If so, can you create a small reproducible
test case for this?

On Mon, Feb 8, 2010 at 12:22 PM, Moritz mor...@cloudme.org wrote:
 Hello everyone,

 in my application I have a scheduled task that runs every 5 minutes to
 update the cache. Currently it is a brute force implementation, that
 runs through all entities and computes all permutations required.

 This task usually takes longer than 30 seconds - and fails almost
 every time with a HardDeadlineExceededError.

 My problem is, that all available information currently is not clear
 about how to handle these errors. Maybe I missed it, but:

 - The documentation is only about bandwidth, number of requests, API
 calls etc.
 - The API provides methods to measure number of CPU cycles
 (getCpuTimeInMegaCycles()), but doesn't warn about reaching the limit
 - In the discussion group I find some information such as maximum
 duration of 30 seconds for each request, but that is actually quite
 unspecific.
 - HardDeadlineExceededError is not documented in the API docs.
 Somewhere I read that a DeadlineExceededException should be thrown
 before - but I catch any Exception and still produce a
 HardDeadlineExceededError

 Of course, I could now just use a timer to run my job and terminate it
 gracefully shortly before 30 seconds are reached. But I'd prefer a
 better, more predictable and reliable option. Any suggestions?

 Thanx,
 Moritz

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Re: [appengine-java] Question on request duration / quota / HardDeadlineExceededError

2010-02-08 Thread John Patterson

HDEEs can be thrown without a DEE if it happens in your own code.
Usually the most time consuming thing is waiting for API calls to
return so a timeout here will result in the API call stopping with a
DEE. So if you do not call the API often you can hit HDEE directly.

I also have long running tasks that iterate through data processing
and storing results. I use an Iterator that stops returning results
after 20 seconds and saves the last object processed and then kicks
off a new task to continue processing.

My original solution caught the DEE and then cleaned up but this
stopped working reliably.

On 9 Feb 2010, at 01:22, Moritz wrote:

Hello everyone,

in my application I have a scheduled task that runs every 5 minutes to
update the cache. Currently it is a brute force implementation, that
runs through all entities and computes all permutations required.

This task usually takes longer than 30 seconds - and fails almost
every time with a HardDeadlineExceededError.

My problem is, that all available information currently is not clear
about how to handle these errors. Maybe I missed it, but:

- The documentation is only about bandwidth, number of requests, API
calls etc.
- The API provides methods to measure number of CPU cycles
(getCpuTimeInMegaCycles()), but doesn't warn about reaching the limit
- In the discussion group I find some information such as maximum
duration of 30 seconds for each request, but that is actually quite
unspecific.
- HardDeadlineExceededError is not documented in the API docs.
Somewhere I read that a DeadlineExceededException should be thrown
before - but I catch any Exception and still produce a
HardDeadlineExceededError

Of course, I could now just use a timer to run my job and terminate it
gracefully shortly before 30 seconds are reached. But I'd prefer a
better, more predictable and reliable option. Any suggestions?

Thanx,
Moritz

[appengine-java] Re: Dynamic properties (Expando model) possible with Java?

2010-02-08 Thread datanucleus

To add properties to classes at runtime, you need to build your
classes dynamically, and then enhance them, and define the metadata
for them dynamically too. All been done before, see this link
http://www.jpox.org/servlet/wiki/pages/viewpage.action?pageId=6619188

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[appengine-java] Image API Transparency cut

2010-02-08 Thread Millisecond

Hey all,

I'm trying to take a PNG that has all pixels filled with nothing
transparent, and cut out part of that image along a predefined
mask.  So I would end up with an image that is part transparent and
part filled.

Is this possible with the Image API?  The only way I'm able to punch
out pixels of an originating image appears to be with a full color
value not a transparent pixel.

Thanks,
-Casey

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[appengine-java] What is the most optimal way to delete and create objects in the datastore?

2010-02-08 Thread RSN

Hi,

I am kind of new to GAE, and I was wondering if someone has statistics
or data that shows what are the most optimal (efficient) ways for
deleting and creating objects in the Datastore.

I did some small experiments in order to identify a more efficient
mechanism to delete and create objects in the datastore. In these
tests, I have a single persistent object that contains 8 persistent
fields.

In the first test, I have a loop of 150 instances, and at each
iteration I create the persistent object, and I call the
makePersistent function to add the single instance to the datastore.
This should take much longer, and it does. It takes on average 16-17
seconds.

In the second test, the loop only creates the 150 objects, and then
outside the loop, I call the makePersistentAll function, passing all
my collection of objects. As it is mentioned in the documentation,
this is supposed to be faster, and it is. It takes on average 1-2
seconds.

I have experimented only with one way for deleting objects.
Basically, I make a query to retrieve ONLY the keys of my
objects.
Query query = pm.newQuery(select objectKey from  +
objectClass.getName());
keys = (ListKey) query.execute();

Then, once all keys have been retrieved, I call the following service
method:
DatastoreService ds = DatastoreServiceFactory.getDatastoreService();
ds.delete(keys);

To delete the objects. It takes on average 2-4 seconds to delete 150
instances.

I was just wondering if I am missing something, and if there is a more
efficient way for deleting (or creating) objects in the datastore. I
see also that there is a higher variance in deleting objects than in
creating them. For example, the fastest run in my test took 1.6
seconds to delete the 150 instances, while the slowest run took almost
8 seconds. I do not see this variability when I create the objects
(i.e., when I add them to GAE).

Any advice or suggestions on alternative methods for doing these kinds
of operations in GAE is GREATLY APPRECIATED. Or, If I am in the right
track, please let me know.

THANKS A LOT.






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Re: [appengine-java] Seeing owned/child entities in the datastore viewer

Sounds like a pretty cool feature. Go ahead and add it to our feature
request list:

http://code.google.com/p/googleappengine/issues/list?can=2q=datastore+viewer

On Tue, Feb 2, 2010 at 8:10 PM, Daniel Benamy dben...@gmail.com wrote:

Hi,

I'm trying to find a way to see the relationships between entities in
the data store viewer. If I have:
class A {
B foo;
}
and I'm looking at an instance of A in the data store viewer, is there
any way for me to find its B? I feel like this should be pretty simple
and maybe I'm just missing something dumb but I've searched a bunch
and can't figure this out. I know I can work backwards and find a
parent from its child by decoding its key. But my app can obviously go
the other way and it would make my life easier if I could too. Can
anyone help?

Thanks,
Dan

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Re: [appengine-java] Re: JDO model issue

2010-02-08 Thread Rusty Wright


I agree with Jake; relationships are tricky.  Likewise with his pointing out 
that having race be in two Results will be a problem; that won't fly.

Another way would be to have a ListResult in Race, and add your Results to 
that.  But you're still going to have parenting problems when you have the same 
runner in different races; that's where I'd store the Runner's Key in the Result.

Having the Result query the datastore seems odd to me; I was thinking of doing that but 
it seems to me that these persistent objects ought to be fairly simple data transfer 
objects and shouldn't be doing that.  The DAO does the datastore interactions.  If you 
were doing the fully layered way, with domain objects (that is, these data transfer 
objects), DAOs, and a service layer, I could see the service layer calling the DAOs, and 
then it calls the setters on the domain objects to fill in the missing stuff, like the 
Race in the Result here.  But that seems dirty to me; shouldn't the ORM be 
doing this for us?


Jake wrote:

Hey,

Relationships in GAE are a bit picky.  It is my understanding that you
can only persist children by way of persisting their parents.  So, in
your case, both Race and Runner are children of Result and you would
only persist the two result objects - the dependent children would be
persisted automatically.  I'm willing to bet, though, that a single
race object cannot be the child of two different parent objects,
though I'm not certain.  The details are all here:
http://code.google.com/appengine/docs/java/datastore/relationships.html

For the most part, I've found that parent/child relationships are only
useful when the two are highly related - usually when I'm extending a
class to provide more data.  (e.g. Race - RaceDetails).

The easy way to get around this is to store the objects in unowned
relationships, referencing other objects by IDs as described in
http://code.google.com/appengine/docs/java/datastore/relationships.html#Unowned_Relationships.
Then, with some fancy getters/setters that automatically query the
Datastore, you end up with the same result.  See my example below.

If anyone has any other advice, though, please contribute.  I haven't
found a great way to handle this and I'm trying to avoid using GAE
specific libraries to help.

Jake

public class Race {

   private Key id;
   ...
}

public class Result {

   private Key id;
   private Key raceId;

   public Race getRace() {
   //query datastore with getObjectById(Race.class, raceId);
   }
}

On Feb 6, 7:15 pm, Rodolphe rde...@gmail.com wrote:

Hello,

I am very new to appengine, and I am trying a very basic model exemple: A
Race class is linked to a Runner class through a Result class

When I am running the folloging code (the full code is attached):
Race race = new Race(Paris, new Date(), 10);

Runner runner1 = new Runner(Smith);
Runner runner2 = new Runner(John);

Result result1 = new Result(race, runner1, 1);
Result result2 = new Result(race, runner2, 2);

PersistenceManager pm = PMF.get().getPersistenceManager();
try {
race = pm.makePersistent(race);

runner1 = pm.makePersistent(runner1);
runner2 = pm.makePersistent(runner2);

pm.makePersistent(result1);
pm.makePersistent(result2);
} finally {
pm.close();
}

I get the following error:
Detected attempt to establish Result(4) as the parent of Runner(2) but the
entity identified by Runner(2) has already been persisted without a parent.
A parent cannot be established or changed once an object has been persisted.
org.datanucleus.store.appengine.FatalNucleusUserException: Detected attempt
to establish Result(4) as the parent of Runner(2) but the entity identified
by Runner(2) has already been persisted without a parent.  A parent cannot
be established or changed once an object has been persisted.
at
org.datanucleus.store.appengine.DatastoreRelationFieldManager.checkForParentSwitch(DatastoreRelationFieldManager.java:204)
at
org.datanucleus.store.appengine.DatastoreRelationFieldManager$1.setObjectViaMapping(DatastoreRelationFieldManager.java:125)
at
org.datanucleus.store.appengine.DatastoreRelationFieldManager$1.apply(DatastoreRelationFieldManager.java:104)
at
org.datanucleus.store.appengine.DatastoreRelationFieldManager.storeRelations(DatastoreRelationFieldManager.java:78)
at
org.datanucleus.store.appengine.DatastoreFieldManager.storeRelations(DatastoreFieldManager.java:812)
at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertPostProcess(DatastorePersistenceHandler.java:288)
at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObjects(DatastorePersistenceHandler.java:241)
at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObject(DatastorePersistenceHandler.java:225)
at

[appengine-java] Re: Persistence with JPA + GAE

Hello,

The Google Datastore has four ways that you can store a Primary Key
ID:  String, Long, and two variations on Google's own Key object.  If
you want to create a parent/child relationship between two persisted
objects (in your case, evento is the parent and distritos is the
child), then you need to use Google's Key object as the primary ID.
See:  
http://code.google.com/appengine/docs/java/datastore/creatinggettinganddeletingdata.html#Keys
If the class is used as a child class in a relationship, the key
field must be of a type capable of representing an entity group
parent: either a Key instance, or a Key value encoded as a string.
So, you have two options:

1.  Change your Long id values to Key id values.
2.  Instead of storing private distritos distrito directly in your
evento object, store a reference to the id: private Long distrito_id

Jake

On Feb 6, 4:06 pm, chevelle jvall...@vnperu.com wrote:
 Hi
 I am new in the list, in these days i am trying save data between two
 entity beans using JPA but without success, i am cheking the log nd
 says:

 Uncaught exception from servlet
 javax.persistence.PersistenceException: Error in meta-data for
 beans.distritos.id: Cannot have a java.lang.Long primary key and be a
 child object (owning field is beans.evento.distrito).

 this is my servlet:
             Long id =
 Long.parseLong(request.getParameter(idDistrito));
             response.setContentType(text/html);
             EntityManager cn = emf.get().createEntityManager();

             Query q = cn.createQuery(SELECT d FROM distritos d WHERE
 d.id = :codigo);
             q.setParameter(codigo,id);
             distritos dist = (distritos) q.getSingleResult();

             EntityManager cn2 = emf.get().createEntityManager();
             cn2.getTransaction().begin();

             evento e = new evento();
             e.setDistrito(dist);
             Date fecha = new Date();
             e.setFechaCreacion(fecha);

             try{
                 cn2.persist(e);
                 response.getWriter().write(ok);
             }finally{
                 cn2.getTransaction().commit();
                 cn2.close();
             }

 this is my entity bean

 Evento:
 @Entity
 public class evento implements Serializable {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     Long id;

     @Temporal(javax.persistence.TemporalType.DATE)
     private Date fechaCreacion;

     @JoinColumn
     @OneToMany(cascade = CascadeType.ALL)
     private distritos distrito;

    --getter and setter--

 Distrito:
 @Entity
 public class distritos implements Serializable {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     Long id;
     private String distrito;

     --getter and setter--

 i hope anyone help me, Thank!

 Johan

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Re: [appengine-java] Re: Persistence with JPA + GAE


hi jake, thank for you answer
i will try you suggestion and i will tell later

El 08/02/2010 03:37 p.m., Jake escribió:

Hello,

The Google Datastore has four ways that you can store a Primary Key
ID:  String, Long, and two variations on Google's own Key object.  If
you want to create a parent/child relationship between two persisted
objects (in your case, evento is the parent and distritos is the
child), then you need to use Google's Key object as the primary ID.
See:  
http://code.google.com/appengine/docs/java/datastore/creatinggettinganddeletingdata.html#Keys
If the class is used as a child class in a relationship, the key
field must be of a type capable of representing an entity group
parent: either a Key instance, or a Key value encoded as a string.
So, you have two options:

1.  Change your Long id values to Key id values.
2.  Instead of storing private distritos distrito directly in your
evento object, store a reference to the id: private Long distrito_id

Jake

On Feb 6, 4:06 pm, chevellejvall...@vnperu.com  wrote:
   

Hi
I am new in the list, in these days i am trying save data between two
entity beans using JPA but without success, i am cheking the log nd
says:

Uncaught exception from servlet
javax.persistence.PersistenceException: Error in meta-data for
beans.distritos.id: Cannot have a java.lang.Long primary key and be a
child object (owning field is beans.evento.distrito).

this is my servlet:
 Long id =
Long.parseLong(request.getParameter(idDistrito));
 response.setContentType(text/html);
 EntityManager cn = emf.get().createEntityManager();

 Query q = cn.createQuery(SELECT d FROM distritos d WHERE
d.id = :codigo);
 q.setParameter(codigo,id);
 distritos dist = (distritos) q.getSingleResult();

 EntityManager cn2 = emf.get().createEntityManager();
 cn2.getTransaction().begin();

 evento e = new evento();
 e.setDistrito(dist);
 Date fecha = new Date();
 e.setFechaCreacion(fecha);

 try{
 cn2.persist(e);
 response.getWriter().write(ok);
 }finally{
 cn2.getTransaction().commit();
 cn2.close();
 }

this is my entity bean

Evento:
@Entity
public class evento implements Serializable {
 @Id
 @GeneratedValue(strategy = GenerationType.IDENTITY)
 Long id;

 @Temporal(javax.persistence.TemporalType.DATE)
 private Date fechaCreacion;

 @JoinColumn
 @OneToMany(cascade = CascadeType.ALL)
 private distritos distrito;

--getter and setter--

Distrito:
@Entity
public class distritos implements Serializable {
 @Id
 @GeneratedValue(strategy = GenerationType.IDENTITY)
 Long id;
 private String distrito;

 --getter and setter--

i hope anyone help me, Thank!

Johan
 
   


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Re: [appengine-java] Localization parameters

I saw this blog post the other day (It was posted on our Twitter account):

http://blog.jteam.nl/2010/02/04/free-java-hosting-with-the-google-app-engine/

The tip is to add this to your web.xml:

context-param
param-namejavax.servlet.jsp.jstl.fmt.timeZone/param-name
param-valueGMT+1:00/param-value
/context-param

http://blog.jteam.nl/2010/02/04/free-java-hosting-with-the-google-app-engine/Does
this do what you need?

2010/2/3 Grégoire Galinand gregoire.galin...@gmail.com

Hi, i've got a little problem with localization settings when i deploy
my applications.

I'm in france and when i format a date with a simpledateformat, i've
got a offset of 2 hours with my french clock.

How can i define my localizations parameters for my application ?

Thanks

Grégoire

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Developer Programs Engineer, Google App Engine
http://googleappengine.blogspot.com | http://twitter.com/app_engine

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Re: [appengine-java] Is there an equivalent of Python GeoModel project in Java?

Looks like someone ported the Python code to Java for GeoHash:

http://stackoverflow.com/questions/2060219/google-app-engine-geohashing

Also seems like a pretty good explanation of GeoHashing in general.

On Thu, Feb 4, 2010 at 10:16 AM, mianor lefebvre.rom...@gmail.com wrote:

Hi,

I am trying to implement geolocation search with GAE in Java using
GeoPt.
But due to restrictions on Datastore, bounding box queries are also
not supported in App Engine because there need to be two inequalities
on two independent properties (latitude and longitude).

There seems to be a solution with Geohash but every thing I found is
based on GAE Python. Is there anything based on Java or can I use
Geomodel (http://code.google.com/p/geomodel/) from Python in my Java
applications?

Thanks for your help!

Romain

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http://googleappengine.blogspot.com | http://twitter.com/app_engine

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Re: [appengine-java] Where to report server down time?

What does the server log report at this time? Can you post a stack trace?

On Fri, Feb 5, 2010 at 6:20 AM, Bob F robertfolke...@gmail.com wrote:

I tried to open http://folkertsfotografie.appspot.com and recieved
Error: Server Error
The server encountered an error and could not complete your request.

If the problem persists, please report your problem and mention this
error message and the query that caused it.

several times. I followed the link to an app engine page, hoping that
it would be a form to tell either Google or the author (me) that the
application was down. Is this a frequent occurrence with AppEngine?

Is there a log of application failures like this?

Eventually, the application can up (with no change in code). My
application is written in Grails with the AppEngine plugin.

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Re: [appengine-java] Getting the client's timezone