date:20100311

[appengine-java] Re: Why I encountered this error : The class java.lang.String is not persistable.

2010-03-11 Thread Ian Marshall

DataNucleus: OK.

Jolam: how did you fix your problem?

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Re: [appengine-java] log4j init fails

2010-03-11 Thread AJ Chen

I have the default log4j.properties in WEB-INF/classes dir. but the warning
always comes up. the file is visible because I can change the log level to
ERROR to get rid of the warning.
-aj

On Fri, Feb 19, 2010 at 7:24 PM, Rusty Wright rwright.li...@gmail.comwrote:

I think you can simply put the log4j.properties file in the WEB-INF/classes
dir and you don't need any appengine-web.xml stuff for it. Log4j looks for
its configuration file on the classpath which means it looks in
WEB-INF/classes (and also in all of the jars in the lib directory).

AJ Chen wrote:

I have log4j config in appengine-web.xml,
system-properties
property name=java.util.logging.config.file
value=WEB-INF/logging.properties/
property name=log4j.configuration
value=file:WEB-INF/classes/log4j.properties/
property name=monitor.config.file
value=WEB-INF/monitor.properties/
/system-properties
but GAE still complains about it:
log4j:WARN No appenders could be found for logger
(DataNucleus.Connection).
log4j:WARN Please initialize the log4j system properly.

Is there anything else that should be set?

thanks,
-aj

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--
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Chair, Semantic Web SIG, sdforum.org
http://web2express.org
twitter @web2express
Palo Alto, CA, USA
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Re: [appengine-java] How to query objects with criterias defined in child entities

2010-03-11 Thread Jeff Schnitzer

On Wed, Mar 10, 2010 at 7:39 PM, John Patterson jdpatter...@gmail.com wrote:
 On 11 Mar 2010, at 03:40, Jeff Schnitzer wrote:

 That is an empty claim with no example or evidence.  Every comparison we
 have see so far is cleaner  and more readable in Twig.

Nonsense.  The only example that was cleaner and more readable in
Twig was a single and extremely contrived case based on a pattern
that nobody is actually using.  And even that is no longer prettier in
Twig.

 Readability is not even the most important issue here:  Objectify model's
 dependence on low-level Keys means that *all* code that uses you data (the
 entire application) must also be dependent on the low-level datastore.

Let's think for a minute why anyone cares if Key, Email, GeoPt, Link,
etc shows up in higher levels of an application:  portability.  Unless
you're working on Twig for other datastores, this entire line of
thought is moot.  If you use Twig for data access, you're stuck on
GAE.  If you use Objectify for data access, you're stuck on GAE.

The only data access API that gives you any hope (tenuous as it is) of
real portability is JDO/JPA.

Without portability, all this talk of polluting the higher tiers of
your application with datastore classes is a whole lot of religious
claptrap.

In my development with Objectify, I haven't found it necessary to use
Key objects in the higher levels of my app - just at the level of
DAOs.  However, I do use GeoPt a lot.  There are a lot of things that
might change if I had to port away from GAE, and this is just one of
them.

Sure, some data access frameworks can help portability more than
others, but if you are really concerned about moving off of GAE - you
want JPA.

 This what is going on under the covers in Twig is suddenly the
 responsibility of the developer with Objectify.  As pointed out above, this
 makes Objectify applications less portable.

Hmmm.  Except that what is going on under the covers in Twig
requires Twig, and Twig is not portable.  You seem to be making a
pretty good case for JDO/JPA.

 The success of projects like Hibernate grew from the fact that users don't
 want to deal with implementation details in their business logic.

The success of projects like Hibernate grew from the giant chasm
between objects and relational databases.  There were some solutions
that did more and some solutions that did less.  Hibernate did about
the right amount of stuff and had what for the time was a fairly
elegant API.

It's not always the case that doing more is better - JPA won out over
JDO.  Even hibernate ended up throwing out some major features (anyone
remember top level collections?)

The trick will be threading the needle between features and
complexity.  You weigh features more heavily, I weigh simplicity more
heavily.

 Oh come on!  What is so difficult to understand here?  Calling
 refresh(Object) gets the latest data from the datastore.

Actually, it was quite confusing, and I'm not just being
argumentative.  Until you posted your delete example, it was not
apparent that your entity POJOs have lifecycle state; a POJO in an
entity graph might have been loaded from the database or it might be
empty, despite having a valid key.

Now it makes sense why you need a refresh() method.

I don't like the idea of entities that look like User #1234 but don't
have the data of User #1234.  This feels like it has a lot of bug
potential to me.

 Objectify has, basically,
 four methods:  get(), put(), delete(), and query().  They work exactly
 the way you would expect.

 I wouldn't say that - why does Query extend QueryResultIterator?  This is
 not at all expected.  I could call offset() on your Query in the middle of
 iterating through its results... the API seems to suggest that is possible.
  Quite weird.

You may be the only one confused by this, probably because you didn't
read the documentation properly:  Query extends QueryResultIterable,
not QueryResultIterator.

And yes, you can call offset(5), then iterator(), then call
offset(10), and call iterator() again.  Each iterator will iterate
normally as you expect.

Once again, this allows queries to be elegantly run like this:

for (Car car: ofy.query(Car.class).filter(weight , 5000)) {
doSomethingWith(car);
}

...which, while not being a major bullet point, is at least an mild
ergonomic win for Objectify.

 Twig adds quite a few API methods and the docs don't make it clear
 what they do.  What are refresh(), update(), storeOrUpdate(),
 associate(), and disassociate()?

 Of course Twig has more API methods than Objectify - Objectify does not
 manage instance identity.

Managing instance identity is not that hard.  It's a simple @Id field,
just like the @Id you are familiar with in JPA.  Maybe an additional
@Parent in the rare case you need one.  Not that complicated.

 The code is generally a lot more descriptive and fluent which helps
 understanding more than depending on JavaDocs.

As someone who has read your documentation with more

[appengine-java] Re: Why I encountered this error : The class java.lang.String is not persistable.

2010-03-11 Thread Jolam

Actually i have encounter new problems...I will ask for help in a new
post...

On Mar 11, 4:01 pm, Ian Marshall ianmarshall...@gmail.com wrote:
 DataNucleus: OK.

 Jolam: how did you fix your problem?

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[appengine-java]confusion about entities group and transaction.

2010-03-11 Thread Jolam

I have defined two classes named TotalInformation and UrlInformation:


TotalInformation:

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

@Persistent
private int urlNumber;

UrlInformation

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

@Persistent
private String url = new String();

@Persistent
private String code = new String();
___

Both have no reference to each other.
I retrieve TotalInformation and make a key to create a UrlInformation
in the same transaction and finally i store them like this :
__
tx.begin();
code = UrlConverter.getStringByNumber(total.getUrlNumber());
total.setUrlNumber(total.getUrlNumber() + 1);
KeyFactory.Builder keyBuilder = new
KeyFactory.Builder(TotalInformation.class.getSimpleName(),PropertiesGetter.getProperty(administation.totalInfomation.id));
keyBuilder.addChild(UrlInformation.class.getSimpleName(), code);
Key key = keyBuilder.getKey();
UrlInformation thisUrl = new UrlInformation();
thisUrl.setKey(key);
//
pm.makePersistent(thisUrl);
tx.commit();
pm.close();
___

the transaction didn't rollback which i suppose the two entities are
in the same entities group and i found two entities in http://
localhost:/_ah/admin and found the two entities with the keys
below respectively:

TotalInformation:
agpqaWFuZy1zZmdsciELEhBUb3RhbEluZm9ybWF0aW9uIgsxNTAxNzUwMjEyNQw
UrlInformation:
agpqaWFuZy1zZmdscjYLEhBUb3RhbEluZm9ybWF0aW9uIgsxNTAxNzUwMjEyNQwLEg5VcmxJbmZvcm1hdGlvbiIBMQw

But when i create keys to retrieve UrlInformation and TotalInformation
and i encounter :

javax.jdo.JDOFatalUserException: Illegal argument
NestedThrowables:
java.lang.IllegalArgumentException: can't operate on multiple entity
groups in a single transaction. found both Element {
  type: TotalInformation
  name: 15017502125
}
 and Element {
  type: UrlInformation
  name: d
}

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[appengine-java] Re: confusion about entities group and transaction.

2010-03-11 Thread Jolam

What i'm gonna ask is how can i store two class with no reference to
each other in a single transaction and how can i retrieve them , edit
and store them in a single transaction.

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[appengine-java] Re: Where can i specify my log file name in Google Web App ?

2010-03-11 Thread mallubk

Thank you Ian Marshall,

I want to log all diagnostic messages in a file by specify file name
in Log4j.properties file

as below:

log4j.appender.myapp.file=C:/MyTestAppLogs.log

but its not working... any idea ?


Thanks,

MallikarjunBK


On Mar 11, 1:54 am, Ian Marshall ianmarshall...@gmail.com wrote:
 I use both files, located in:

   war\WEB-INF\classes\log4j.properties
   war\WEB-INF\classes\logging.properties

 In my appengine-web.xml file, I have the following extract for you:

   ?xml version=1.0 encoding=UTF-8?
   appengine-web-app xmlns=http://appengine.google.com/ns/1.0;
     system-properties
       property
        name=java.util.logging.config.file
        value=WEB-INF/classes/logging.properties
       /
       property
        name=log4j.configuration
        value=file:WEB-INF/classes/log4j.properties
       /
     /system-properties
   /appengine-web-app

 I remember that I had a problem where the two file names included
 capital letters, so reluctantly I made them both pure lower case!

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Re: [appengine-java] Objectify - Twig - approaches to persistence

2010-03-11 Thread John Patterson


On 11 Mar 2010, at 16:27, Jeff Schnitzer wrote:

On Wed, Mar 10, 2010 at 7:39 PM, John Patterson  
jdpatter...@gmail.com wrote:

On 11 Mar 2010, at 03:40, Jeff Schnitzer wrote:
That is an empty claim with no example or evidence.  Every  
comparison we

have see so far is cleaner  and more readable in Twig.


Nonsense.  The only example that was cleaner and more readable in
Twig was a single and extremely contrived case based on a pattern
that nobody is actually using.  And even that is no longer prettier in
Twig.


Well then, where are your examples?  I responded to the edge cases  
you asked about with a simple example.  Now its your turn to show me  
how Objectify would code the example I asked about.


So wheres the code?  Where is this clean Objectify code you claim is  
possible?  The question is still waiting below


Readability is not even the most important issue here:  Objectify  
model's
dependence on low-level Keys means that *all* code that uses you  
data (the
entire application) must also be dependent on the low-level  
datastore.


Let's think for a minute why anyone cares if Key, Email, GeoPt, Link,
etc shows up in higher levels of an application:  portability.  Unless
you're working on Twig for other datastores, this entire line of
thought is moot.  If you use Twig for data access, you're stuck on
GAE.  If you use Objectify for data access, you're stuck on GAE.


You are still mixing the concepts of data model portability and data  
access layer (DAOs) portability.


Of course the code to actually manipulate data uses a particular  
interface and is dependent on that interface.  The only persistence  
framework I am aware of that approaches complete transparency is  
Terracotta.


I never claimed that Twig code would run on other platforms.  What I  
claimed was that the *data models* are not dependent on the  
datastore.  Generally a lot of application code simply uses data  
without needing to persist changes - especially in webapps.  All of  
this code can remain portable ... unless your data models are not  
portable.



The only data access API that gives you any hope (tenuous as it is) of
real portability is JDO/JPA.


Are you having a laugh?  After all your rants about how portability  
with JDO-GAE is impossible... that is really grasping at straws.


I claim that Twig data models are more portable that JDO-GAE, JPA and  
Objectify data models.  Why?  Because they are pure POJOs with no low  
level datastore dependencies - simple.  Yes you can run JDO on other  
platforms - but


I do not claim that the data access layer is portable - although  
certainly neither is Objectify



Without portability, all this talk of polluting the higher tiers of
your application with datastore classes is a whole lot of religious
claptrap.


It is not important until you hit one of the many show-stoppers that  
these mailing lists are full of.  Then it becomes a little more  
interesting.



In my development with Objectify, I haven't found it necessary to use
Key objects in the higher levels of my app - just at the level of
DAOs.  However, I do use GeoPt a lot.  There are a lot of things that
might change if I had to port away from GAE, and this is just one of
them.


Obviously a rather large one.


The trick will be threading the needle between features and
complexity.  You weigh features more heavily, I weigh simplicity more
heavily.


In a system such as GAE which makes so much so hard productivity  
features are a great relief. No OR queries?  Of course I value  
simplicity - but the whole idea of a framework is to push complexity  
from the user code into the framework.  Objectify leaves too much too  
the developer for my liking.  It is simple - I grant you that - but  
that makes app code more complex.




Oh come on!  What is so difficult to understand here?  Calling
refresh(Object) gets the latest data from the datastore.


Actually, it was quite confusing, and I'm not just being
argumentative.  Until you posted your delete example, it was not
apparent that your entity POJOs have lifecycle state; a POJO in an
entity graph might have been loaded from the database or it might be
empty, despite having a valid key.

Now it makes sense why you need a refresh() method.


It is covered in the docs.  Activation is a central concept with Twig  
- modelled on Db4o.



I don't like the idea of entities that look like User #1234 but don't
have the data of User #1234.  This feels like it has a lot of bug
potential to me.


All referenced objects are activated by default - the developer  
actually has to explicitly choose to use this feature as an  
optimisation so there are no surprises.



Objectify has, basically,
four methods:  get(), put(), delete(), and query().  They work  
exactly

the way you would expect.


I wouldn't say that - why does Query extend QueryResultIterator?   
This is
not at all expected.  I could call offset() on your Query in the  
middle of
iterating through its results...

[appengine-java] Re: confusion about entities group and transaction.

2010-03-11 Thread Ian Marshall

I think that the only way to do this is to have both of your instances
in the same entity group.

So, even though each instance will have no (direct) reference to each
other, they will need to share an entity ancestor (which will ensure
that your instances are in the same entity group (the same entity
group as the common ancestor)).

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[appengine-java] Re: Where can i specify my log file name in Google Web App ?

2010-03-11 Thread Ian Marshall

In fact, I have two log4j.properties files: one for my build
environment and one for running GAE/J (either the development server
on my computer or in the production (cloud) environment). In my
earlier post I mentioned my running properties file only.


BUILD ENVIRONEMNT EXTRACT
-
  log4j.appender.A1=org.apache.log4j.FileAppender
  log4j.appender.A1.File=nbproject/Build.log
  log4j.appender.A1.layout=org.apache.log4j.PatternLayout
  log4j.appender.A1.layout.ConversionPattern=%d{HH:mm:ss,SSS} (%t)
%-5p [%c] - %m%n

  log4j.category.DataNucleus=WARN, A1


PRODUCTION ENVIRONEMNT EXTRACT
--
  log4j.appender.A1=org.apache.log4j.ConsoleAppender
  log4j.appender.A1.layout=org.apache.log4j.PatternLayout
  log4j.appender.A1.layout.ConversionPattern=%d{HH:mm:ss,SSS} (%t)
%-5p [%c] - %m%n

  log4j.category.DataNucleus=WARN, A1


Of course, our apps cannot write to file when running under GAE
(either dev or production), hence my use of the console appender
instead of the file appender.

I know little about Log4J, but for your build environment you might
care to alter the wording of your file appender line

  log4j.appender.myapp.file=C:/MyTestAppLogs.log

to

  log4j.appender.myapp.File=C:/MyTestAppLogs.log

but I do not know if Log4J is case sensitive like this.

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[appengine-java] Precompilation fails

2010-03-11 Thread guillaume

Hi,

I manage the Google App Engine module for the Play! java web framework
(http://www.playframework.org). While generated applications run
correctly on the local and production runtimes, the precompilation
process always fail.

It seems that any war generated by play cannot be precompiled (So for
example this app: http://play-lists.appspot.com).

It's true that we are doing a lot of very dirty hacks in play
framework...
But any chance to have a hint on why the precompilation process fail?
This way I could try to find a fix.

Thank you.

Guillaume.

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[appengine-java] Re: Not able to write string arrays in data store

2010-03-11 Thread Ganesh

Hi,

Thanks for your response...I dont have my code with me right now..I
will post it in a day or two. Meanwhile, do you have any example of
handling two dimensional arrays into two separate lists of ArrayList?

-Thanks
Ganesh

On Mar 10, 5:17 pm, Robert Lancer robert.lan...@gmail.com wrote:
 Just use two separate lists of ArrayListString and it should work
 fine. Also you have to test for null whenever you pull anything out of
 datastore, something like

 if null then return new ArrayListString(0)

 should work this case.

 On Mar 10, 4:28 pm, thierry Le conniat thlec...@euriware.fr wrote:



  Hello,
  how to do you retreive data , could you send jour java code ?

  On 10 mar, 17:28, Ganesh ganeshkumar.marimu...@gmail.com wrote:

   Hi,

   I am trying to store two dimensional string array in google data
   store. I was getting an exception saying this data type not supported.
   I tried changing the string array object to java.util.arraylist (gave
   serizable = 'true' option). This time I was able to write the data
   successfully. But when I tried to retrieve it, I am facing null
   pointer exception. Can any body help me with this?

   -Thanks
   Ganesh- Hide quoted text -

 - Show quoted text -

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[appengine-java] Re: Not able to write string arrays in data store

2010-03-11 Thread datanucleus

 I tried changing the string array object to java.util.arraylist (gave
 serizable = 'true' option). This time I was able to write the data
 successfully. But when I tried to retrieve it, I am facing null
 pointer exception.

Perhaps if you actually posted the NPE+stack trace, and code used to
retrieve it then someone could point out the problem ;-)

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[appengine-java] Cloud2db - JDBC driver for Google Android platform

2010-03-11 Thread Sandeep

Hi Everyone,

Cloud2db is pleased to announce the availability of Cloud2db JDBC
driver for Google Android platform. With this driver you will be able
to access your Cloud2db instance from the Android applications using
standard JDBC concepts. Please download the Cloud2db Server and JDBC
driver from the following following link, 
http://cloud2db.appspot.com/website/download.html.

Cloud2db provides a standards-based abstraction layer over Google
Datastore (Bigtable).  This product provides you with performance and
scalability of GAE along with structure, standards and
interoperability of RDBMS, SQL and JDBC.

With Cloud2db, you will be able to manage your data on Google
Datastore by using established concepts of RDBMS, SQL and JDBC, and
thereby preserving your existing investments in tools, technologies,
frameworks and skills.

Here are Cloud2db features:

Manage data on Google Datastore using familiar concepts of RDBMD, SQL
. Referential integrity (Primary Keys, Foreign Keys)
. Role Based Security
. Joins (Inner Join, Left Outer Join, Theta Join, Cross Join)
. Subqueries (Exists, Not Exists, In)
. DDL  DML
. Transactions
. ANSI SQL stored functions
. Views
. BLOB and CLOB support

Use any JDBC compliant tools and frameworks in the market to interact
with the Google Datastore. For example.
. Squirrel SQL (database management)
. Power Architect (data modeling)
. Jasper Reports (reporting)
. Hibernate (Object To Relational mapping)
. All JDBC compliant tools

Port exiting RDBMS instances to Google Datastore

Please visit our website http://www.cloud2db.com and try out the free
trial version of our product by downloading it at
http://cloud2db.appspot.com/website/download.html. Please visit google
group Cloud2db to share your feedback and thoughts.

Sincerely,

Sandeep Sathaye
Founder and Chief Architect
Cloud2db

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[appengine-java] Re: elegant way of implementing sequence generator

2010-03-11 Thread legendlink

Hi blake,

could you give me simple example on how to use the @version, or any
reference material?

thanks!

On Mar 9, 11:35 pm, Blake blakecaldw...@gmail.com wrote:
 You could also go with the sharded counter strategy.  The more shards
 you have, the less the chance that you'll have a collision, and you'd
 use @Version for optimistic locking on each shard.

 On Mar 9, 7:18 am, legendlink gregc...@gmail.com wrote:

  Thanks for the reply.

  If memcache is used, how do I implement it so that the counter would
  always be updated and not be deleted?

  On Mar 6, 4:35 am, Ikai L (Google) ika...@google.com wrote:

   Have you looked into Memcache's INCR?

  http://code.google.com/appengine/docs/java/javadoc/com/google/appengi...,
   long)

   This'll do it atomically, but you run the risk of it being volatile,
   so you'll have to account for that in your client code.

   On Tue, Mar 2, 2010 at 11:40 PM, legendlink gregc...@gmail.com wrote:
hi, i wanted to have a sequence generator that increments by x value
everytime it generates a value. if i would create the sequence
generator by using the datastore, it is likely that data contention
would occurr if there is high access times.

i have looked into the sample code of max ross in the google code
repository (SequenceExamplesJDO.java) and  think this is limited to
increment by 1 only and not increment by x value.

if sharding technique is used, my concern is that i might not get the
right sequence.

what is the best/elegant way of doing sequence generator that
increments x value?

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[appengine-java] 30 second error after commit transaction

2010-03-11 Thread legendlink

Could someone confirm if my thinking is correct regarding the status
of datastore  if the 30 seconds timeout occurs in the timeline below?

start of servlet
...
some process
...
transaction start
... --- a) 30 second timeout!
some process
... --- b) 30 second timeout!
commit transaction
... --- c) 30 second timeout!
close persistence manager
... --- d) 30 second timeout!
process
... --- e) 30 second timeout!
end of servlet

A) not committed
B) not committed
C) committed
D) committed
E) committed

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Re: [appengine-java] log4j init fails

2010-03-11 Thread Rajeev Dayal

If you have your log4j.properties file at the root of your source tree, it
should automatically be copied over to war/WEB-INF/classes whenever Eclipse
performs a build of your project; you should not have to copy it over
manually.

I'm not sure why you're getting the error with regard to
Datanucleus.Connection; I've added Don to this thread; he may have some
insight into this.

On Thu, Mar 11, 2010 at 3:33 AM, AJ Chen ajc...@web2express.org wrote:

I have the default log4j.properties in WEB-INF/classes dir. but the warning
always comes up. the file is visible because I can change the log level to
ERROR to get rid of the warning.
-aj

On Fri, Feb 19, 2010 at 7:24 PM, Rusty Wright rwright.li...@gmail.comwrote:

I think you can simply put the log4j.properties file in the
WEB-INF/classes dir and you don't need any appengine-web.xml stuff for it.
Log4j looks for its configuration file on the classpath which means it
looks in WEB-INF/classes (and also in all of the jars in the lib directory).

AJ Chen wrote:

Is there anything else that should be set?

thanks,
-aj

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[appengine-java] Re: App instance recycling and response times - is there solution?

2010-03-11 Thread James

I setup some pings of my add a few minutes ago, and I'm still seeing
recycling :(

My ping setup can't go lower than 60s intervals, so I have two running
concurrently.  Here's a sample of 20 log entries over 10 minutes,
with .  Three recyclings occur, and they happen less than 10s after a
previous request.  Really Google, you're killing my JVM after TEN
SECONDS?  And I get to pay you for the ton of CPU each startup uses?
Sounds like the more recycling, the more profitable the App Engine
becomes.


-
* 03-11 08:02AM 38.506 /?Pragma=no-cache 200 2158ms 2235cpu_ms 0kb
Site 24 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 08:02AM 23.144 /?Pragma=no-cache 200 53ms 19cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 08:01AM 06.134 /?Pragma=no-cache 200 75ms 19cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 08:00AM 51.707 /?Pragma=no-cache 200 49ms 19cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 08:00AM 05.823 /?Pragma=no-cache 200 49ms 58cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:59AM 51.499 /?Pragma=no-cache 200 56ms 38cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:59AM 05.584 /?Pragma=no-cache 200 47ms 19cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:58AM 51.274 /?Pragma=no-cache 200 61ms 38cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:58AM 05.371 /?Pragma=no-cache 200 64ms 19cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:57AM 51.025 /?Pragma=no-cache 200 74ms 19cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
* 03-11 07:56AM 57.327 /?Pragma=no-cache 200 7835ms 2119cpu_ms 0kb
Site 24 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:56AM 50.784 /?Pragma=no-cache 200 75ms 58cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:55AM 57.008 /?Pragma=no-cache 200 50ms 19cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
* 03-11 07:55AM 46.384 /?Pragma=no-cache 200 4250ms 2060cpu_ms 0kb
Site 24 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:54AM 56.782 /?Pragma=no-cache 200 70ms 38cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:54AM 46.157 /?Pragma=no-cache 200 54ms 38cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:53AM 56.586 /?Pragma=no-cache 200 52ms 19cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:53AM 45.934 /?Pragma=no-cache 200 51ms 38cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:52AM 56.240 /?Pragma=no-cache 200 62ms 38cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:52AM 45.718 /?Pragma=no-cache 200 57ms 19cpu_ms 0kb Site 24
X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
-



On Jan 30, 11:02 pm, Alyxandor a.revolution.ultra.b...@gmail.com
wrote:
 If you are experiencing failed requests on your long-running /
 requests, consider performing some kind of pre-warming procedure of
 your own...  If you are getting timeout errors, Ping a do-nothing url,
 and wait for it to return before running the big job.  If it's a big
 job, users should expect to wait anyway {and you should tell them they
 are waiting!}, so the ping ensures {almost} that a warm JVM is running
 in the server nearest said users, and then the big /request can
 {usually} avoid getting killed with extra spin up time.  Very unlucky
 users would get a /ping on an old JVM, and /request a new one, but...
 Technology isn't perfect...  YET!

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Re: [appengine-java] Re: How exactly do the App Engine Logs work?

2010-03-11 Thread Don Schwarz

On Wed, Mar 10, 2010 at 8:05 PM, Spines kwste...@gmail.com wrote:

 Sorry, I don't think I really understood the task queue approach. To
 ensure no loss of data, would the task have to update in the datastore
 every time?  And the benefit over just doing it directly in the
 servlet handler would be the faster response time to the user?


Basically, yes.


 I think the memcache solution may be my best bet.  I can tolerate some
 chance of loss of data.  I'm wondering how likely loss of data would
 be? How often does the data get booted out? If I persist from memcache
 to datastore every 10 seconds would data loss be super rare?


You would have to experiment with this as we don't make any guarantees, but
I believe that memcache data generally survives much longer than 10 seconds
of inactivity, yes.

On Mar 10, 4:11 pm, Spines kwste...@gmail.com wrote:
  Thanks Don,
  I thought about the task queue, but that caps at being able to execute
  like 5 tasks per second right?
 
  So, as long as the log data doesn't get full before I download it then
  it would be fine?
 
  On Mar 10, 3:42 pm, Don Schwarz schwa...@google.com wrote:
 
 
 
   Yeah, those are diagnostic logs.  They effectively go into a ring
 buffer per
   logging level, so the maximum data stored at any given time is capped.
  The
   more you log, the more frequently you would have to download the logs
 to
   avoid missing any.  You would also be competing with log space with any
   other log messages generated by your application.
 
   What I would suggest instead is either to increment counters in
 memcache,
   and flush them to the datastore periodically if you need durability
 (I'm
   assuming you can tolerate some chance of data loss here).  If you
 cannot
   tolerate any loss of data, then I would suggest enqueueing tasks to a
 task
   queue for each request that maintains a summary in memcache and/or the
   datastore.
 
   On Wed, Mar 10, 2010 at 4:59 PM, Spines kwste...@gmail.com wrote:
I'm talking about the logs that get written when I call
Logger.info(something).
 
Basically this is what I'm thinking: I have certain data that needs
 to
get written very often, but hardly ever needs to be read (stuff like
what users view what pages of my site).  The datastore is optimized
for read efficiency. So, I want to output this data to the logs. I
will have an offsite computer download these logs, do calculations on
them, and upload the result of the calculations to the datastore.
 
On Mar 10, 2:03 pm, Don Schwarz schwa...@google.com wrote:
 Are you talking about request logs or diagnostic logs?  Although we
conflate
 them a bit in both the Admin Console viewer and the appcfg command,
 but
they
 are stored and tracked separately.
 
 On Wed, Mar 10, 2010 at 4:01 PM, Spines kwste...@gmail.com
 wrote:
  Hmm, that is my biggest concern, log reliability.  Can someone
 from
  Google confirm whether or not I can rely on the logs having all
 of the
  log data? Or might certain entries just disappear?
 
  On Mar 10, 1:24 pm, thierry Le conniat thlec...@euriware.fr
 wrote:
   Hello,
   I think google log are stored in file.
   My experience about log reliability is that when the app is
 very
   strong working, not all the log are stored.
   It's confusing, but i can't not explain it.
 
   Bye
 
   On 10 mar, 22:04, Spines kwste...@gmail.com wrote:
 
Where does Google store the logs when you do a Logging
 statement?
Logging statements seem to be pretty fast, so it doesn't seem
 like
they are stored in the datastore.
 
How reliable are the logs? If I do a logging statement and it
succeeds, is it pretty much guaranteed that it will show up
 in the
logs?
 
How much past history of logs is stored?
 
The reason I'm interested in this is because I'm making a
 question
and
answer website, and I want to keep track of views by each
 unique
logged in user to each question, and display the view count
 on the
question page. So if 10 different users visit the question
 page 100
times, it still only counts as 10 unique views.
 
I have an offsite computer that does background processing
 for my
app.
I'm planning to have this offsite computer download the logs
 about
every 30 minutes, and calculate what the view count should be
 for
each
question based off of the logs. By doing this, I don't have
 to
create
a datastore entity for each different question each user
 views.
 
What do you guys think? Does anyone see any problems with
 this?
 
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[appengine-java] Re: elegant way of implementing sequence generator

2010-03-11 Thread datanucleus

 could you give me simple example on how to use the @version,

The DataNucleus docs define that, and much more
http://www.datanucleus.org/products/accessplatform/jdo/orm/versioning.html

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[appengine-java] Re: confusion about entities group and transaction.

2010-03-11 Thread Jolam

It's the kind-hearted man Ian Marshall again. :)
I have solved the problem mentioned above by setting the key of a
class to be stored a key with common ancestor like u said.
But there's one thing i think we should noticed that if we retrieve a
entity by a key with no parents ,say we create it by KeyFactory using
the key's name like:

KeyFactory.createKey(a.class.getSimpleName(),name);

it can still be retrieve but it seems that the app engine don't
recognize it a entity in same entity group with others.That is to say,
we can't manipulate it with other entites that is in the same entity
group in the same transaction.

but if we create a key like this:
KeyFactory.createKey(parents.class.getSimpleName,a.class.getSimpleName(),name);
Everything's alright.

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Re: [appengine-java] log4j init fails

2010-03-11 Thread AJ Chen

yes, log4j.properties is copied by the build. the app uses it. the warning
message is weird. thanks.

On Thu, Mar 11, 2010 at 8:10 AM, Rajeev Dayal rda...@google.com wrote:

I'm not sure why you're getting the error with regard to
Datanucleus.Connection; I've added Don to this thread; he may have some
insight into this.

On Thu, Mar 11, 2010 at 3:33 AM, AJ Chen ajc...@web2express.org wrote:

I have the default log4j.properties in WEB-INF/classes dir. but the
warning always comes up. the file is visible because I can change the log
level to ERROR to get rid of the warning.
-aj

On Fri, Feb 19, 2010 at 7:24 PM, Rusty Wright rwright.li...@gmail.comwrote:

I think you can simply put the log4j.properties file in the
WEB-INF/classes dir and you don't need any appengine-web.xml stuff for it.
Log4j looks for its configuration file on the classpath which means it
looks in WEB-INF/classes (and also in all of the jars in the lib directory).

AJ Chen wrote:

Is there anything else that should be set?

thanks,
-aj

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Re: [appengine-java] Re: App instance recycling and response times - is there solution?

2010-03-11 Thread Don Schwarz

Can you respond privately with your app id?

On Thu, Mar 11, 2010 at 10:10 AM, James jamesk...@gmail.com wrote:

 I setup some pings of my add a few minutes ago, and I'm still seeing
 recycling :(

 My ping setup can't go lower than 60s intervals, so I have two running
 concurrently.  Here's a sample of 20 log entries over 10 minutes,
 with .  Three recyclings occur, and they happen less than 10s after a
 previous request.  Really Google, you're killing my JVM after TEN
 SECONDS?  And I get to pay you for the ton of CPU each startup uses?
 Sounds like the more recycling, the more profitable the App Engine
 becomes.


 -
 * 03-11 08:02AM 38.506 /?Pragma=no-cache 200 2158ms 2235cpu_ms 0kb
 Site 24 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 08:02AM 23.144 /?Pragma=no-cache 200 53ms 19cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 08:01AM 06.134 /?Pragma=no-cache 200 75ms 19cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 08:00AM 51.707 /?Pragma=no-cache 200 49ms 19cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 08:00AM 05.823 /?Pragma=no-cache 200 49ms 58cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:59AM 51.499 /?Pragma=no-cache 200 56ms 38cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:59AM 05.584 /?Pragma=no-cache 200 47ms 19cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:58AM 51.274 /?Pragma=no-cache 200 61ms 38cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:58AM 05.371 /?Pragma=no-cache 200 64ms 19cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:57AM 51.025 /?Pragma=no-cache 200 74ms 19cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
 * 03-11 07:56AM 57.327 /?Pragma=no-cache 200 7835ms 2119cpu_ms 0kb
 Site 24 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:56AM 50.784 /?Pragma=no-cache 200 75ms 58cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:55AM 57.008 /?Pragma=no-cache 200 50ms 19cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
 * 03-11 07:55AM 46.384 /?Pragma=no-cache 200 4250ms 2060cpu_ms 0kb
 Site 24 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:54AM 56.782 /?Pragma=no-cache 200 70ms 38cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:54AM 46.157 /?Pragma=no-cache 200 54ms 38cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:53AM 56.586 /?Pragma=no-cache 200 52ms 19cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:53AM 45.934 /?Pragma=no-cache 200 51ms 38cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:52AM 56.240 /?Pragma=no-cache 200 62ms 38cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
  03-11 07:52AM 45.718 /?Pragma=no-cache 200 57ms 19cpu_ms 0kb Site 24
 X 7 RPT-HTTPClient/0.3-3E,gzip(gfe)
 -



 On Jan 30, 11:02 pm, Alyxandor a.revolution.ultra.b...@gmail.com
 wrote:
  If you are experiencing failed requests on your long-running /
  requests, consider performing some kind of pre-warming procedure of
  your own...  If you are getting timeout errors, Ping a do-nothing url,
  and wait for it to return before running the big job.  If it's a big
  job, users should expect to wait anyway {and you should tell them they
  are waiting!}, so the ping ensures {almost} that a warm JVM is running
  in the server nearest said users, and then the big /request can
  {usually} avoid getting killed with extra spin up time.  Very unlucky
  users would get a /ping on an old JVM, and /request a new one, but...
  Technology isn't perfect...  YET!

 --
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[appengine-java] Re: Not able to write string arrays in data store

2010-03-11 Thread Robert Lancer

Setting:

ListString arrayDim1 = new ArrayListString();
ListString arrayDim2 = new ArrayListString();

entity.setUnindexedProperty(ArrayDim1, arrayDim1 );
entity.setUnindexedProperty(ArrayDim2, arrayDim2 );

Unless your looking to run queries against the lists use the
setUnindexedProperty.

Getting:

ListString arrayDim1 = (ListString)
entity.getProperty(ArrayDim1);
ListString arrayDim2 = (ListString)
entity.getProperty(ArrayDim2);

if (arrayDim1 != null)

if(arrayDim2 != null)





On Mar 11, 9:41 am, Ganesh ganeshkumar.marimu...@gmail.com wrote:
 Hi,

 Thanks for your response...I dont have my code with me right now..I
 will post it in a day or two. Meanwhile, do you have any example of
 handling two dimensional arrays into two separate lists of ArrayList?

 -Thanks
 Ganesh

 On Mar 10, 5:17 pm, Robert Lancer robert.lan...@gmail.com wrote:



  Just use two separate lists of ArrayListString and it should work
  fine. Also you have to test for null whenever you pull anything out of
  datastore, something like

  if null then return new ArrayListString(0)

  should work this case.

  On Mar 10, 4:28 pm, thierry Le conniat thlec...@euriware.fr wrote:

   Hello,
   how to do you retreive data , could you send jour java code ?

   On 10 mar, 17:28, Ganesh ganeshkumar.marimu...@gmail.com wrote:

Hi,

I am trying to store two dimensional string array in google data
store. I was getting an exception saying this data type not supported.
I tried changing the string array object to java.util.arraylist (gave
serizable = 'true' option). This time I was able to write the data
successfully. But when I tried to retrieve it, I am facing null
pointer exception. Can any body help me with this?

-Thanks
Ganesh- Hide quoted text -

  - Show quoted text -

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[appengine-java] Re: Objectify - Twig - approaches to persistence

2010-03-11 Thread Bob

I've recently converted from JDO to Twig.  I've been able to remove an
optimization hack that queried the datastore every 15 minutes to cache
data from a 1+ minute operation.  I can now have end users execute
essentially that same logic in real time.

Have not tried Objectify so I can't comment on the comparison.  From a
framework perspective I'm in the camp of give me an easy and clean
way to do what I do 80% of the time, and a low-level way to do
anything else I need to do.

-Bob

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[appengine-java] Unable to replace JPACallbackHandler

2010-03-11 Thread Thom Nichols

I'm attempting to build a simple Java app, but as soon as I call
pm.makePersistent( entity ) I get this error.  I've only seen a couple
other instances of this problem (here's one:
http://groups.google.com/group/google-appengine-java/browse_thread/thread/ec3beda8fbd9c154
).

I don't believe this is an issue with the old datanucleus JAR on the
classpath; here's my WAR's lib dir:
appengine-api-1.0-sdk-1.3.1.jar
datanucleus-appengine-1.0.5.final.jar
datanucleus-core-1.1.5.jar
datanucleus-jpa-1.1.5.jar
geronimo-jpa_3.0_spec-1.1.1.jar
jdo2-api-2.3-eb.jar
jta-1.1.jar
jython-2.5.0.jar
slf4j-api-1.5.11.jar
slf4j-jdk14-1.5.11.jar
standard-1.1.2.jar

Other details are here:
http://code.google.com/p/maven-gae-plugin/issues/detail?id=49colspec=ID%20Type%20Status%20Priority%20Milestone%20Owner%20Version%20Summary

I'm unable to determine if this is a maven plugin problem or not at
this point.  Any help is appreciated -- thanks.

-Tom

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[appengine-java] Equality operator with range uery not working properly

2010-03-11 Thread Abhi

Hi All,

I am facing problem with a query

when i am adding filter with equality operator (== set) and providing
range, it gives all the records.

Please help me.

Thanks,
Abhi

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[appengine-java] Re: Equality operator with range uery not working properly

2010-03-11 Thread datanucleus

 when i am adding filter with equality operator (== set) and providing
 range, it gives all the records.

You don't quote the query, nor the query mechanism (local API, JDO,
JPA, who knows what) so am doubting you will get a reply without such
infos

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Re: [appengine-java] Newwwwbie

2010-03-11 Thread Ikai L (Google)

Quick thing to try: run the server as Debug and not Run. This
allows for hot class reloading.

On Thu, Mar 11, 2010 at 12:27 AM, Thanks in Advance
mikeashie...@gmail.com wrote:
I started at:
http://code.google.com/appengine/docs/java/gettingstarted/usingusers.html
but am laughably stuck at

To allow the user to sign out, provide a link to the sign-out screen,
generated by the method createLogoutURL().

despite looking through the documentation at:
http://code.google.com/appengine/docs/java/javadoc/com/google/appengine/api/users/UserService.html

Also, I can't seem to get my Eclipse/Java application to re-compile/
update without restarting the server.

Obviously I am new to Java/GAE but would be really appreciative of
help in even how to read the documentation etc.

Suggestions of Java/Eclipse basic tutorial or references would be
great too.

Thanks in advance

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Re: [appengine-java] Unable to upload app: Error posting to URL:

2010-03-11 Thread Ikai L (Google)

Yes, you will have to specify your proxy settings.

On Tue, Mar 9, 2010 at 8:32 AM, WillSpecht willspe...@gmail.com wrote:
 I am getting the following error when trying to upload my app to app
 engine.  What does the 302 Redirected mean?  I am behind a proxy could
 this be part of the problem?

 Error
 Tue Mar 09 11:12:47 EST 2010
 Unable to upload app: Error posting to URL:
 http://appengine.google.com/api/appversion/create?app_id=black3liveversion=1302
 Redirected


 See the deployment console for more details

 com.google.appengine.tools.admin.AdminException: Unable to upload app:
 Error posting to URL: 
 http://appengine.google.com/api/appversion/create?app_id=black3liveversion=1;
 302 Redirected

 at
 com.google.appengine.tools.admin.AppAdminImpl.update(AppAdminImpl.java:
 59)
 at
 com.google.appengine.eclipse.core.proxy.AppEngineBridgeImpl.deploy(AppEngineBridgeImpl.java:
 271)
 at
 com.google.appengine.eclipse.core.deploy.DeployProjectJob.runInWorkspace(DeployProjectJob.java:
 148)
 at
 org.eclipse.core.internal.resources.InternalWorkspaceJob.run(InternalWorkspaceJob.java:
 38)
 at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)
 Caused by: java.io.IOException: Error posting to URL:
 http://appengine.google.com/api/appversion/create?app_id=black3liveversion=1;
 302 Redirected

 at
 com.google.appengine.tools.admin.ServerConnection.send(ServerConnection.java:
 143)
 at
 com.google.appengine.tools.admin.ServerConnection.post(ServerConnection.java:
 81)
 at
 com.google.appengine.tools.admin.AppVersionUpload.send(AppVersionUpload.java:
 415)
 at
 com.google.appengine.tools.admin.AppVersionUpload.beginTransaction(AppVersionUpload.java:
 229)
 at
 com.google.appengine.tools.admin.AppVersionUpload.doUpload(AppVersionUpload.java:
 98)
 at
 com.google.appengine.tools.admin.AppAdminImpl.update(AppAdminImpl.java:
 53)

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Re: [appengine-java] Simple query

2010-03-11 Thread Ikai L (Google)

The dev appserver is a simulator, not a true emulator. It'll run much
slower locally than in production because in production Google uses
BigTable, scalable email service, scalable XMPP, scalable task
executor, etc.

On a side note, this is the lesser of two evils, anyway. Anyone that
has done iPhone development knows that the simulator runs FASTER in
development that it does on a real device. As you can tell this leads
to problems ...

On Thu, Mar 11, 2010 at 2:03 PM, Karel Alvarez kalvar...@gmail.com wrote:
 wow!, seriously? is this in the docs?? I don't recall ever reading
 about the dev server being significantly slower than production, for
 only one user, one request?

 No, I don't have the code in production, I would not put a code in
 production that I know for sure (now I know better) is not going to
 perform under 30 secs...

 I will post comments when I move this to production and give it a try
 there... I will take time to collect the data from production...

 thanks for replying!, was about to migrate the whole think to .net...,
 it is slow, but consistent :-)


 On Thu, Mar 11, 2010 at 4:49 PM, Ikai L (Google) ika...@google.com wrote:
 Oh, this is slow locally? Yes, that makes sense. Our local datastore
 stub isn't meant to run fast. We're thinking of replacing the flatfile
 stub with SQLite, which would mitigate the pain slightly. How does it
 run in production?

 On Thu, Mar 11, 2010 at 1:25 PM, Karel Alvarez kalvar...@gmail.com wrote:
 what kind of benchmarking you need? I could send you the local_db.bin
 file? and the code, and you can debug it line by line, it is pretty
 ovbious when that one line takes minutes to run...

 thanks!
 Karel

 On Thu, Mar 11, 2010 at 3:16 PM, Ikai L (Google) ika...@google.com wrote:
 This shouldn't take that long to run. Can you post any other code or
 benchmarking code?

 On Sun, Mar 7, 2010 at 6:33 PM, Karel Alvarez kalvar...@gmail.com wrote:
 Hi guy,
 I hate to bother everybody again.
 I have a ver simple class, some fields, and an String primary key. One
 of the fields lastTimeIndexed is a date.
 I am trying to get the max value for it, the folowing method working
 fine upto 3k records, but now I added more, and it takes minutes to
 run.
 I have the autoGenerate flag set to true in the datastore-indexes.xml,
 and also the datastore-indexes-auto.xml file...
 here is the code, what is wrong with it?? can anybody think of a
 better way of doing this??

 public Date getLastDate() {
                Date lastDate = null;
                PersistenceManager pm = getPersistenceManager();
                Query query = pm.newQuery(IndexEntry.class);
                query.setOrdering(lastTimeIndexed desc);
                query.setRange(0, 1);
                query.setUnique(true);
                try {
                        IndexEntry entries = (IndexEntry) query.execute();
                        if (entries != null) {
                                lastDate = entries.getLastTimeIndexed();
                        }
                } finally {
                        query.closeAll();
                }
                return lastDate;
        }

 thanks
 Karel

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[appengine-java] How to delete all entities of a kind with the datastore viewer

2010-03-11 Thread Spines

I'm only able to delete 20 entities at a time,  I have over 500
entities of a certain kind. Is there a  way I can delete them all from
the admin console?

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Re: [appengine-java] Objectify - Twig - approaches to persistence

2010-03-11 Thread Jeff Schnitzer

I'll try to ignore the blatent trolls.  But you want things easier to
do in Objectify than Twig, so here's a few:

-

How, in Twig, do you rename a field?

Objectify lets you import data from a variety of historical formats;
as you load and save data it will naturally be transformed in format:

class Person {
@Id Long id;
int age;
@AlsoLoad(name) String fullName;
}

Now, assume that the user has queries like:

QueryPerson q = ofy.query(Person.class).filter(age , 65);

Does this query still work in your system?  If so: After a few
renames, how many queries will you be running?  Can you do batch gets
on their ids?  I mean, after you implement batch gets, of course.

Versions are an ugly solution to this problem and they make a giant
mess out of the datastore.

-

How, in Twig, do you retire an Enum value?

class Car {
@Id Long id;
int year;
Color color;
public void migrateColor(@AlsoLoad(color) value) {
if (AQUA.equals(value))
color = Color.BLUE;
else
color = Color.valueOf(value);
}
}

-

How, in Twig, do you make an entity cached?  If it's in your docs, it
is not easy to find.  The Objectify version:

@Cached(expirationSeconds=600)  // optional expiration
class Person {
...
}

-

How, in Twig, do you load a variety of different objects in parallel?

MapKeyObject, Object result = ofy.get(
 new KeyCar(Car.class, carId),
 new KeyPerson(Person.class, personId),
 new KeyPlant(Plant.class, plantId));

-

  Usability, performance and maintainability are the strengths of Twig I
 would prefer to focus on.

All I seem to see you focusing on is OR, the bizarre notion that
addFilter() is somehow more maintainable than filter(), and an
even stranger notion that someone will be confused by iterable
queries.

I don't want to knock the OR feature, but it's hardly the must-have
feature you make it out to be.  In the GAE issues list, OR support
doesn't even make the first two pages, ranking it somewhere below
Erlang and TCL support.  I couldn't even find an issue for it.
Obviously there are a *lot* of people building applications on GAE
without OR in the framework, and they don't seem to be complaining too
loudly about it.

Maybe you're right, and we'll see a giant land rush for OR support.
Except that Twig has supported OR queries for quite some time, and it
still hasn't been getting traction.

You might very well have something with parallel queries.  As with all
asynchronous code, they come at a cost of maintainability, but for
some - maybe even many - applications, parallel queries could be a
game changer.  Rest assured, we will be watching.

 I don't deny that the developer could hit an initialized object.  But given
 that they have to explicitly turn on this feature I think you are
 over-stating the danger.  The advantages are huge - POJOs and cleaner code.

I'm simply offering you the lessons that others have learned
developing a highly analogous feature (proxies) in Hibernate.  It
isn't that proxies aren't useful, it's that they get screwed up a lot.
 As someone that has done a lot of work with Hibernate proxies, I can
tell you firsthand that they can be very difficult to get right in a
complicated schema.  And hollow entities which nominally work but
return invalid data will be worse.

Again, it is not my intention to say this feature is inherently wrong
or bad - but that it's not the great revolution that you make it out
to be.  It comes with a cost which the Objectify developers are not
currently willing to pay.

 Yep.  Objectify entities are plain, boring POJOs that work just like
 every other Java object.  You can load them, clone them, save them,
 serialize them in and out, whatever.  There is no magic.

 I would hardly call an object with such restrictions a POJO.

You seem to have an odd definition of Plain Old Java Object.  POJOs
can be copied, created, cloned, whatever.  You can have two of them in
memory with the same id.

This is actually pretty core to the philosophy of Objectify:  We hate
magic.  We're pretty resistant to features that are not transparent,
and when we do implement features that are magical (like @Embedded),
we document the hell out of it.

Hollow, stateful entities with lifecycles are pretty magical.
Cascading loads and saves are pretty magical.  POJOs and Keys are
simple.

 My real world application is not possible with Objectify!!  It uses OR
 queries executed in parallel.
 [...much other conversation...]
 OR's are essential - batch gets are a trivial feature that will be added
 with the load command.

Essential?  So all those applications deployed on GAE right now
(including mine) don't exist?

Jeff

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[appengine-java] Re: datanucleus enhancer keeps running

2010-03-11 Thread lp

i tried using gae sdk 1.3.1 but still got enhancer looping.

it seems to happen when i include spring 3.x libs i dunno giving
up and going for ant task.

-lp

On Mar 3, 1:43 am, Rajeev Dayal rda...@google.com wrote:
 Seehttp://code.google.com/p/googleappengine/issues/detail?id=2115. This may
 be the issue that you're having. It was recently fixed, and a version of GPE
 with the fix is forthcoming.

 On Thu, Feb 25, 2010 at 1:57 PM, Steve Pritchard steve...@gmail.com wrote:

  On Feb 25, 6:39 am, haole mejoe...@gmail.com wrote:
   i'm using eclipse 3.5.1, GPE 3.5 (1.2.0.v200912062003), GAE
   1.3.1.v201002101412, GWT 2.0.3.v201002191036
   datanucleusenhancer continuously runs over and over again
   temporary workaround: turn off build automatically feature in eclipse

  I have several projects with a dependency hierarchy.  I found the
  enhancer to be fragile and it often would not enhance the classes.   I
  had to do a 'clean' to make it happen. I could not find the pattern to
  when it failed to enhance.  It never looped on me so you may be seeing
  a different problem.

  About 3 weeks ago I had had enough and  turned off the Enhancer
  builder (the plugin yelled at me).  In its place I added an ant task
  to do the enhancement.  I derived the ant task statements from the
  Datanucleus site.  Since that time things have been very stable and
  the enhancer always finishes its job.

  This is the essence of the ant task:

   !--
   --
   !--                          T A S K D E F
  S                         --
   !--
   --

   taskdef name=enhance
  classname=com.google.appengine.tools.enhancer.EnhancerTask
       classpath
         pathelement path=${appengine.tools.classpath}/
         pathelement path=${appengine.tools.lib}/
       /classpath
   /taskdef

   !--
   --
   !--                          T A R G E T
  S                           --
   !--
   --

   target name=enhance.cls
       description=Performs Datnucleus JDO enhancement on compiled
  data classes.
     !-- echo message= path ${appengine.tools.classpath}/ --
     !-- echo message= fileset ${proj.dir.gen.cls}/ --
     enhance failonerror=true verbose=false
       classpath
         pathelement path=${appengine.tools.classpath}/
         fileset dir=${proj.dir.war.lib} includes=*.jar/
         pathelement path=${proj.dir.gen.cls}/
       /classpath
       fileset dir=${proj.dir.gen.cls} includes=**/*.class/
     /enhance
   /target

   target name=enhance.war
       description=Performs Datnucleus JDO enhancement on war
  classes.
     !-- echo message= path ${appengine.tools.classpath}/ --
     !-- echo message= fileset ${proj.dir.gen.cls}/ --
     enhance failonerror=true verbose=false
       classpath
         pathelement path=${appengine.tools.classpath}/
         fileset dir=${proj.dir.war.lib} includes=*.jar/
         pathelement path=${proj.dir.war.cls}/
       /classpath
       fileset dir=${proj.dir.war.cls} includes=**/*.class/
     /enhance
   /target

  It may be worth a try.
  Steve

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[appengine-java] Re: How do I write data in my Google App Engine Datastore to com.google.appengine.api.datastore.Text

2010-03-11 Thread Tristan

Lloyd,

String reallyLong = It was the best of times, it was the worst of
times. (...) ..;

Text myText = new Text(reallyLong);

I don't understand your reference to setMethod().

Cheers!

On Mar 10, 10:53 pm, Lloyd cled...@gmail.com wrote:
 I have persistent object, with a string property that often is over
 500 charachters. Google App Engine says I need to save it as a
 com.google.appengine.api.datastore.Text.

 How do I either convert a String type to a
 com.google.appengine.api.datastore.Text type so I can use a
 setMethod() on the property, or otherwise get my long sting data into
 that persistent value?

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[appengine-java] Re: Not able to write string arrays in data store

2010-03-11 Thread Ganesh

This is the class which I wanted to write into datastore:

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

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

@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Question {
@PrimaryKey
@Persistent
private String Pid;
@Persistent
public ListObject Cellval;

public void setQuestion(String progid, String[][] cellval)
{
this.Pid = progid;
this.Cellval = new ArrayListObject(cellval.length);
for(int i = 0; i  cellval.length; i++) {
ArrayListString Temp2 = new
ArrayListString(Arrays.asList(cellval[i]));
this.Cellval.add(Temp2);
}

}

public Question()
{
}


public void setPid(String pid)
{
this.Pid = pid;
}

public String getPid()
{
return(this.Pid);
}

public String[][] getCellval()
{
String[][] tempstr = new String[20][20];
for(int i = 0; i this.Cellval.size();i++)
{
tempstr[i+1] = (String[])
((ArrayList)this.Cellval.get(i)).toArray();
}
return tempstr;
}
}



I write it using below mentioned lines from a different class:

public void writeQuestion(Question Q1)
{
   PersistenceManager pm = PMF.get().getPersistenceManager();
try {
pm.makePersistent(Q1);
} finally {
pm.close();
}

}


I am getting the below mentioned exception while executing this
'INSERT' action:

java.lang.IllegalArgumentException: java.util.ArrayList is not a
supported property type.
at
com.google.appengine.api.datastore.DataTypeUtils.checkSupportedSingleValue(DataTypeUtils.java:
114)
at
com.google.appengine.api.datastore.DataTypeUtils.checkSupportedValue(DataTypeUtils.java:
99)
at com.google.appengine.api.datastore.Entity.setProperty(Entity.java:
257)
at
org.datanucleus.store.appengine.DatastoreFieldManager.storeObjectField(DatastoreFieldManager.java:
757)
at
org.datanucleus.state.AbstractStateManager.providedObjectField(AbstractStateManager.java:
1011)
at com.cword.proj.Question.jdoProvideField(Question.java)
at com.cword.proj.Question.jdoProvideFields(Question.java)
at
org.datanucleus.state.JDOStateManagerImpl.provideFields(JDOStateManagerImpl.java:
2597)
at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObject(DatastorePersistenceHandler.java:
180)
at
org.datanucleus.state.JDOStateManagerImpl.internalMakePersistent(JDOStateManagerImpl.java:
3067)
at
org.datanucleus.state.JDOStateManagerImpl.makePersistent(JDOStateManagerImpl.java:
3043)
at
org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:
1258)
at
org.datanucleus.ObjectManagerImpl.persistObject(ObjectManagerImpl.java:
1135)
at
org.datanucleus.jdo.JDOPersistenceManager.jdoMakePersistent(JDOPersistenceManager.java:
668)
at
org.datanucleus.jdo.JDOPersistenceManager.makePersistent(JDOPersistenceManager.java:
693)
at com.cword.proj.AccessQuestions.writeQuestion(AccessQuestions.java:
80)
at org.apache.jsp.Temp_jsp._jspService(Temp_jsp.java:111)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
at
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:
324)
at
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:
292)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
at com.google.appengine.tools.development.PrivilegedJspServlet.access
$101(PrivilegedJspServlet.java:23)
at com.google.appengine.tools.development.PrivilegedJspServlet
$2.run(PrivilegedJspServlet.java:59)
at java.security.AccessController.doPrivileged(Native Method)
at
com.google.appengine.tools.development.PrivilegedJspServlet.service(PrivilegedJspServlet.java:
57)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:
487)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1093)
at
com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:
43)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1084)
at
org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:
360)
at

[appengine-java] Cryptography on App Engine

2010-03-11 Thread Spines

Anyone know of a reliable Java library for cryptography that works on
the app engine?  I want to encrypt with AES.

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[appengine-java] Re: Reporting on GAE in Java

2010-03-11 Thread David

Update:

This website (http://www.jscriptive.org/2009/08/jasperreports-and-
google-appengine.html) appears to confirm that it's a real issue
rather than simply something I've done wrong or overlooked.

This website (http://code.google.com/p/g2-report-engine/wiki/
AppEngineSupport) seems to be a basic reporting tool that's
specifically designed to work with GAE/J, albeit without the support
of report building tools such as JasperReports' iReport.

I'm still on the lookout for alternative reporting solutions if anyone
can help me out?

Cheers,
David

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[appengine-java] Re: Cryptography on App Engine

2010-03-11 Thread Spines

I think bouncy castle is a good library to use, does anyone know if it
works on the app engine?

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Re: [appengine-java] Objectify - Twig - approaches to persistence

2010-03-11 Thread John Patterson



On 12 Mar 2010, at 05:45, Jeff Schnitzer wrote:

How, in Twig, do you rename a field?


I'm glad you brought this up.  I've found simple renames are better  
handled at the low level - no need to rehydrate them into instances  
just to rename a property.


But for typesafe changes large or small Twig supports data migration  
in a much safer, more flexible way than Objectify.  Read on for details.



Objectify lets you import data from a variety of historical formats;
as you load and save data it will naturally be transformed in format:

class Person {
   @Id Long id;
   int age;
   @AlsoLoad(name) String fullName;
}


Cool, the @AlsoLoad is quite a neat feature.  Although very limited to  
simple naming changes and nothing structural.  All this is based on a  
dangerous assumption that you can modify live data in place.  Hardly  
bullet proof.


The Twig solution is to create a new version of the type (v2) and  
process your changes while leaving the live data completely isolated  
and safe.  Then after you have tested your changes you bump up the  
version number of your live app.


So basically:

1 - Create your new class PersonNew and set its version to 2

@Version(2)
class PersonNew {
 int age;
String fullName;
}

2 - Configure the Kind name to be the same e.g. P (short kind  
names save DS space)


3 - Load your old Person instances and for each store a new PersonNew  
instance.


Your data is now upgraded.

4 - Now you can just replace Person with PersonNew in your code and  
deploy a new version.


5 - Test the version.  This crucial step is not possible with  
Objectifies solution.


6 - Only when you are happy your changes are correct make the new  
version live.  The new data version will be used and you can delete  
your old data when you want.


So you see the Twig method of data migration is much safer than  
Objectifies.  It has the following advantages:


1 - You don't eve have a half-updated schema
2 - Tt works for major structural changes rather than just trivial  
field renames.

3 - You can test the new data structure before going live
4 - You can revert back to you old data structure

The versions remain completely separate.  Modifying live data in place  
gives me heart pains.




Now, assume that the user has queries like:

QueryPerson q = ofy.query(Person.class).filter(age , 65);

Does this query still work in your system?  If so: After a few
renames, how many queries will you be running?  Can you do batch gets
on their ids?  I mean, after you implement batch gets, of course


What is with your obsession with batch gets?  I understand they are  
central in Objectify because you are always loading keys.  As I said  
already - even though this is not as essential in Twig it will be  
added to a new load command.



Versions are an ugly solution to this problem and they make a giant
mess out of the datastore.


I certainly wouldn't feel comfortable re-factoring my live data  
without testing it.  Having a new version in the datastore is a lot  
safer than modifying in place



How, in Twig, do you make an entity cached?  If it's in your docs, it
is not easy to find.  The Objectify version:


Oops I didn't post the CookBook page in the end.  Rest assured it is a  
trivial addition and I'll update the docs.


It is also often better to cache above the data layer - hardly the  
killer feature you claim.



Maybe you're right, and we'll see a giant land rush for OR support.
Except that Twig has supported OR queries for quite some time, and it
still hasn't been getting traction.


No, ORs were just added last week :)


Again, it is not my intention to say this feature is inherently wrong
or bad - but that it's not the great revolution that you make it out
to be.  It comes with a cost which the Objectify developers are not
currently willing to pay.


I don't blame you.  It was a lot of effort to get right and it works  
very elegantly without the need for bytecode enhancement or dynamic  
proxies.



You seem to have an odd definition of Plain Old Java Object.  POJOs
can be copied, created, cloned, whatever.  You can have two of them in
memory with the same id.


Of course, but a POJO is not something that comes with a list of  
requirements.  I guess the level of plainess can vary :)



This is actually pretty core to the philosophy of Objectify:  We hate
magic.  We're pretty resistant to features that are not transparent,
and when we do implement features that are magical (like @Embedded),
we document the hell out of it.


I think you hit the nail on the head there Jeff.  This is the key  
difference in philosophies I think.  Objectify prefers to keep itself  
simple even if the developer needs to do more work.  Twig prefers to  
move complexity into the framework - at the cost of making the  
framework more complex internally (the API remains simple).


A example of this is Twigs feature:

command.ensureUniqueKey()

Re: [appengine-java] what if I hit memory limit ?

2010-03-11 Thread John Patterson

I've also put the source for my layered cache here:

http://code.google.com/p/stick-cache/

You basically have one interface and 3 implementations: memcache,
datastore, in-memory (LRU ReadWrite locks)

One quite handy thing it does is handle blocking for expensive items.
You can pass a Callable like this:

cache.value(myKey, callable);

If the value exists, return it. If not, then build it but block so
other threads don't try to build it at the same time. Once it is done
update all levels of the cache.

Hope this helps

On 11 Mar 2010, at 03:52, Don Schwarz wrote:

To pick one at random:

http://commons.apache.org/collections/apidocs/org/apache/commons/collections/map/LRUMap.html

On Wed, Mar 10, 2010 at 11:08 AM, Prashant Gupta nextprash...@gmail.com
wrote:

Thanks Don for clarification.

100MB seems sufficient for me. Please suggest me a library for LRU
caching implementation.

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Re: [appengine-java] How to delete all entities of a kind with the datastore viewer

2010-03-11 Thread 杨浩

in the admin console:clike the next 20 entity,then change the brower's
location.href set *size=200* and *offset=0*, enter^ ^
The offset's max is *1000*
Good luck！

2010/3/12 Spines kwste...@gmail.com

 I'm only able to delete 20 entities at a time,  I have over 500
 entities of a certain kind. Is there a  way I can delete them all from
 the admin console?


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Re: [appengine-java] Objectify - Twig - approaches to persistence

2010-03-11 Thread John Patterson



On 12 Mar 2010, at 13:01, Scott Hernandez wrote:

We have a different idea about live systems and managing
upgrades/deployments. To answer the question below, you can always
upgrade the data in place because you will always need a way to load
that data into the current object representation. It just may be that
you need to take the system offline to migrate the data.


In my app taking the system off-line while re-processing the data is  
not an option.  The actual reprocessing can take days.


I see your point though.  My data is mainly static so I don't have the  
issues you describe of keeping the new version in sync with the live  
version.  However, I can think of several solutions to this while  
still having the safety advantage of independent tables in the  
datastore.


The simple way would be to, during the migration period, create both a  
Person and a PersonNew whenever a user makes an edit.


Another way would be to do this transparently by creating a simple  
forked translator that stored the Person as two Entities instead of  
one.  I won't go into details but it is certainly not a major extension.


I would probably go for the first method if it was just for my app -  
but this is the kind of feature that could be pushed into the  
framework to make it easier for others to benefit too.



The versions remain completely separate.  Modifying live data in  
place gives

me heart pains.


Duplicating data (during upgrades) is unacceptable, for my app. It may
be safer to leave the old data, but it is not always possible.


There is no maximum stored data on App Engine.  If you delete the data  
after one day is that still a problem?



I have
a *lot* of data, that was costly to generate (both in terms of network
and cpu) and to store. Jeff, and others on the Objectify list, have
spent a lot of time working on a solution with the goal of keeping the
app up during an upgrade (in simple upgrades), without needing to
migrate all the existing data first, which would require downtime.


Ok I understand.  But that is a big trade-off - saving a day or two  
worth of storage costs in exchange for testability, ability-to-revert  
and the peace of mind that a coding error might corrupt your live data.




If the documentation was *very* clear about this maybe, but as Jeff
said, Hibernates biggest complaint was from new users who got LazyInit
exceptions. This is the same thing you have created, without the
benefit of having an exception. You may just get passed an instance of
an uninitialized object if you aren't careful.


Seems we have both claimed that in Objectify and Twig a careless user  
could delete their own data.  At the end of the day, you can never  
guard against that completely in either framework.


That still does not mean that object activation is not an elegant  
solution to the potential problem of loading too much data.  But keep  
in mind that this is not on by default - by default all data will be  
activated.


I expect that most apps will not even use this feature but it is there  
as an optimisation if needed.


John



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[appengine-java] appcfg.sh not uploading new jars

2010-03-11 Thread Josh H

Hi,

I've uploaded my app numerous times without any problems.
But now when I add a new jars to the WEB-INF/lib dir and then run
appcfg.sh it says 40% Uploading 0 files..
I know for a fact these jars have never been uploaded as part of this
app before.
And when I run the app I get a ClassNotFoundException because it's
looking for a class inside one of the new jars.

The jars i'm uploading are under 10MB and i'm running appcfg.sh on a
mac.

Any help would be much appreciated.

Thanks
Josh

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