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From Denis Magda <dma...@gridgain.com>
Subject Re: OptimizedClassDescriptor verifyChecksum object set as optional
Date Tue, 10 Nov 2015 13:55:47 GMT
It should fail because you send your service impl inside of Callable
compute.call(new Callable(new ExampleServiceImplA()));

Callable is loaded by application class loader and presents on both the 
sender and receiver. This leads to the situation when the receiver tries 
to loads ExampleServiceImplA using the app class loader as well.

To avoid this try to implement IgniteCallable by ExampleServiceImplA and 
send the task this way:

compute.call(new ExampleServiceImplA());


 > I think. If I have lots of type servers. It will be 
ExampleServiceImpl1 2 3 4 5….,will look very bloated.

You can use java 8 closures sending a particular one depending on a 
server type. Will it work for you?
https://apacheignite.readme.io/docs/distributed-closures


Regards,
Denis
On 11/10/2015 4:31 PM, 姜 为 wrote:
> Hi Denis,
>
> I tried your suggested,  here is the code 
> :https://github.com/wmz7year/ignite-test/commit/4eaa4231e165eaa4de00dab94cd394f629e68497
> But I still got ClassNotFoundException.
>
>
>
> I think. If I have lots of type servers. It will be 
> ExampleServiceImpl1 2 3 4 5….,will look very bloated.
>
>> 在 2015年11月10日,下午8:02,Denis Magda <dmagda@gridgain.com 
>> <mailto:dmagda@gridgain.com>> 写道:
>>
>> Jiang,
>>
>> This exception happens exactly because you have two implementations 
>> with the same name. If the names were different you wouldn't get to 
>> the point of checksum validation.
>> Here I fully share Val's opinion that checksum's verification 
>> shouldn't be optional and it's a responsibility of an application to 
>> take care of such situations.
>>
>> I see the following approaches you can use in your code to get 
>> required behavior:
>>
>> 1) As suggested below use the approach with Serializable + 
>> serialVersionUID. It will work;
>>
>> 2) More preferable is to have different implementations with 
>> different names (ExampleServiceImpl1, ExampleServiceImpl2, etc...). 
>> Is there any reasons you can't use this straightforward approach?
>> When the implementations are ready you can put their classes onto 
>> every machine in order to have them in the classpath or you can 
>> leverage IgniteConfiguration.peerClassLoadingEnabled feature.
>> The feature allows to load missing classes from a machine that sends 
>> compute based tasks onto a machine that will execute a task and you 
>> don't need to copy implementations' classes manually at all.
>> You can read more on this here: 
>> https://apacheignite.readme.io/docs/zero-deployment
>>
>> Regards,
>> Denis
>>
>> On 11/10/2015 10:39 AM, 姜 为 wrote:
>>> Hi:
>>>
>>> Here is example: https://github.com/wmz7year/ignite-test
>>>
>>> First start ModuleB, then start ModuleA.
>>>
>>> ModuleB ExampleServiceImpl has three field.
>>>
>>>     ModuleA ExampleServiceImpl has only one field.
>>>
>>> Then throw Exception :
>>>
>>> <邮件 附件.png>
>>>> 在 2015年11月10日,下午2:48,Denis Magda <dmagda@gridgain.com>
写道:
>>>>
>>>> Hi,
>>>>
>>>> +1 to Val.
>>>>
>>>> Actually if you have different class names on different machines 
>>>> (DataEntity, ServiceEntity) I don't realize how you can get to the 
>>>> checksum validation stage.
>>>> In my understanding you should have caught ClassNotFoundException.
>>>>
>>>> Provide me with a full runnable example, I'll run and see what 
>>>> you're trying to implement and at which point you fail.
>>>>
>>>> --
>>>> Denis
>>>>
>>>> On 11/10/2015 9:30 AM, Valentin Kulichenko wrote:
>>>>> Hi,
>>>>>
>>>>> I'm against optional checksum verification. It's not safe, adds 
>>>>> one more
>>>>> configuration property and I don't see any use case that can 
>>>>> require this.
>>>>>
>>>>> I also don't completely understand what you're trying to achieve. 
>>>>> Can you
>>>>> please describe the sequence of serialization/deserialization 
>>>>> events that
>>>>> you expect in your application?
>>>>>
>>>>> -Val
>>>>>
>>>>> On Mon, Nov 9, 2015 at 5:13 PM, 姜 为 <ydswcy513@gmail.com> wrote:
>>>>>
>>>>>> Hi:
>>>>>>
>>>>>>         The implementations name maybe not same.
>>>>>>
>>>>>>         Like my example:
>>>>>>
>>>>>>         class DataEntity {
>>>>>>                 Integer id;
>>>>>>                 string name;
>>>>>>                 Integer age;
>>>>>>
>>>>>>                 ….. and other
>>>>>>
>>>>>>                 Externalizable.read(in){
>>>>>>                         if(in.readBoolean()) {
>>>>>>                 id = in.readInt();
>>>>>>             }
>>>>>>                         same as name,age...
>>>>>>                 }
>>>>>>
>>>>>>         Externalizable.write(out){
>>>>>>             out.writeBoolean(id != null);
>>>>>>             if(id != null) {
>>>>>>                 out.writeInt(id);
>>>>>>             }
>>>>>>             same as name,age...
>>>>>>         }
>>>>>>         }
>>>>>>
>>>>>>         class ServiceEntity {
>>>>>>                 Integer id;
>>>>>>                 Integer age;
>>>>>>
>>>>>>                 …. and other
>>>>>>
>>>>>>                 Externalizable.read(in){
>>>>>>                         if(in.readBoolean()) {
>>>>>>                 id = in.readInt();
>>>>>>             }
>>>>>>             if(in.readBoolean()) {
>>>>>>                 in.readString(); // ignore name
>>>>>>             }
>>>>>>             if(in.readBoolean()) {
>>>>>>                 age = in.readInt();
>>>>>>             }
>>>>>>                         … and other
>>>>>>                 }
>>>>>>
>>>>>>         Externalizable.write(out){
>>>>>>             out.writeBoolean(id != null);
>>>>>>             if(id != null) {
>>>>>>                 out.writeInt(id);
>>>>>>             }
>>>>>>             out.writeBoolean(false); // null for name
>>>>>>                        out.writeBoolean(age != null);
>>>>>>             if(age != null) {
>>>>>>                 out.writeInt(age);
>>>>>>             }
>>>>>>                     … and other
>>>>>>         }
>>>>>>         }
>>>>>>
>>>>>>         The other implementation class can be serialized and 
>>>>>> deserialized
>>>>>> custom rules by Externalizable.read and Externalizable.write.
>>>>>>         Each of the different types of servers property needs are
>>>>>> different,it does not require a complete serialization.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> 在 2015年11月9日,下午10:22,Denis Magda <dmagda@gridgain.com>

>>>>>>> 写道:
>>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> As I understand both servers have different implementations but
the
>>>>>> names of those implementations are the same, correct?
>>>>>>> Because otherwise I don't see how your code could get to the

>>>>>>> point of
>>>>>> checksum validation if one implementation's name is ServiceEntity

>>>>>> while the
>>>>>> other's is DataEntity.
>>>>>>> If my assumptions above are correct then I would recommend to
do the
>>>>>> following:
>>>>>>> 1) Extend Serializable instead of Externalizable
>>>>>>>
>>>>>>> interface Entity extends Serializable {
>>>>>>>     .....
>>>>>>> }
>>>>>>>
>>>>>>> 2) Add custom serialVersionUID to each implementation. This will

>>>>>>> help
>>>>>> you get rid off checksum related exception
>>>>>>> class EntityImpl implements Entity {
>>>>>>> private static final long serialVersionUID = 0L;
>>>>>>> ......
>>>>>>> }
>>>>>>>
>>>>>>>
>>>>>>> Regards,
>>>>>>> Denis
>>>>>>>
>>>>>>> On 11/8/2015 3:27 PM, 姜 为 wrote:
>>>>>>>> Hi guys:
>>>>>>>>
>>>>>>>>      I’m using ignite 1.4.
>>>>>>>>      In IgniteCompute.call will transfer of an object to
the 
>>>>>>>> cluster.
>>>>>>>>     The object should implement Serializable or Externalizable
>>>>>> interface.
>>>>>>>>     OptimizedClassDescriptor.read method will check whether
the 
>>>>>>>> object
>>>>>> is in the same class.
>>>>>>>>     In my use case,I have some type of servers in cluster.
>>>>>>>>     The server type A will check the business,and the server
type B
>>>>>> will persistent data.
>>>>>>>>     There is a entity interface Entity extends Externalizable
have
>>>>>> different implementations on different servers.
>>>>>>>>     Such like this:
>>>>>>>>
>>>>>>>>     interface Entity extends Externalizable {
>>>>>>>>      method a();
>>>>>>>>      method b();
>>>>>>>>              method c();
>>>>>>>>      }
>>>>>>>>
>>>>>>>>      class  ServiceEntity implements Entity {
>>>>>>>>      method a(){
>>>>>>>>              // do something...
>>>>>>>>      }
>>>>>>>>
>>>>>>>>      method b(){
>>>>>>>>              // do something...
>>>>>>>>      }
>>>>>>>>
>>>>>>>>      method c(){
>>>>>>>>              throw new UnsupportedException...
>>>>>>>>      }
>>>>>>>>
>>>>>>>>      Externalizable.read...
>>>>>>>>      Externalizable.write...
>>>>>>>>     }
>>>>>>>>
>>>>>>>>     class DataEntity implements Entity {
>>>>>>>>      method a(){
>>>>>>>>              // do something...
>>>>>>>>      }
>>>>>>>>
>>>>>>>>      method b(){
>>>>>>>>              throw new UnsupportedException...
>>>>>>>>      }
>>>>>>>>
>>>>>>>>      method c(){
>>>>>>>>              // do something...
>>>>>>>>      }
>>>>>>>>
>>>>>>>>      Externalizable.read...
>>>>>>>>      Externalizable.write...
>>>>>>>>     }
>>>>>>>>
>>>>>>>>
>>>>>>>>     And IgniteCompute.call(new IgniteCallable(
>>>>>>>>              public Object call(){
>>>>>>>>                      Entity.a() or b and c;..
>>>>>>>>              }
>>>>>>>>      ));
>>>>>>>>
>>>>>>>>    Different implementations of the same class are to achieve

>>>>>>>> read and
>>>>>> write methods.
>>>>>>>>    But OptimizedClassDescriptor.read will check the class
sum 
>>>>>>>> and throw
>>>>>> ClassNotFoundException.
>>>>>>>>    I recommend verifyChecksum object set as optional,and
I 
>>>>>>>> really need
>>>>>> is change.
>>>>>>>>    Here is my pr:
>>>>>>>> https://issues.apache.org/jira/browse/IGNITE-1854 <
>>>>>> https://issues.apache.org/jira/browse/IGNITE-1854> <
>>>>>> https://issues.apache.org/jira/browse/IGNITE-1854> <
>>>>>> https://issues.apache.org/jira/browse/IGNITE-1854>
>>>>>>>> https://github.com/apache/ignite/pull/200/ <
>>>>>> https://github.com/apache/ignite/pull/200/> <
>>>>>> https://github.com/apache/ignite/pull/200/> <
>>>>>> https://github.com/apache/ignite/pull/200/>
>>>>>>>>
>>>>>>
>>>>
>>>
>>
>


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