Hi there Dharam,
The power of PDX is that you can have object versioning. This means,
that you can add/remove fields to an existing type without the fear of
having to clear & destroy the region. PDX will help you with multiple
versions of the same Customer object. If you were to access a v1 of the
customer the fields from the newer versions would just be null. In
addition if a client were to access a v3 Customer object and it only had
the v1 Customer object definition, it would only be able access the
fields that the v1 object knew about. It will not lose the v3 field
information.
You could test this out by starting a server, and then have a client
push data with different customer object versions.
This WAS part of the reason to go from DataSerializable (no versions) to
PDXSerializable (versions).
The ONLY thing you'll have to watch out for is to change the TYPE of a
field definition. You can add and remove fields at hearts content, but
don't change the type of an existing field.
--Udo
On 12/31/16 22:40, Dharam Thacker wrote:
Hi John,
Thanks for the example! My query is more related to schemaless entity.
*Actually this example refers to domain class "Customer" and converts
pojo to JSON. But that also means it has "schema" [Well defined domain
model -- We know number of attributes and type of attributes in advance].*
I am looking for JSON but I don't have "schema" defined as "Customer".
Why? Because if I setup schema/domain class, then I have to frequently
change my domain class and database while onboarding new column or any
upgrades to existing column,
Thus above step will force me to clear & destroy existing region and
recreate it with new model class and pdx metadata.
_*Let's say from "Source" itself I am receiving json as string and
then I want to store such json document as pdx serializable in region. *_
Then I have 3 ways which I am replicating once again from my first
email as below! Any thoughts for that?
_*Case1: Primary key <java.lang.String>*_
region.put(String.valueOf(i), JSONFormatter.fromJSON(obj.toJSONString()));
For above, I believe it should be --> Region<String,PdxInstance> then
how does it look like in spring data geode xml configuration?
_*Case2: Primary Key <? extends java.lang.Serializable>*_
region.put (new CustomObject() ,
JSONFormatter.fromJSON(obj.toJSONString()));
For above, I believe it should be --> Region<CustomObject,PdxInstance>
then how does it look like in spring data geode xml configuration?
_*Case3: Is below case valid one and recommended ?*_
@Region
Class JSONRegion {
CustomPrimaryKeyObject primaryKey;
JSONObject jsonObject; [org.simple.Json library or Jackson library]
// Constructor + Getter/Setter
}
Thanks & Regards,
- Dharam Thacker
On Sun, Jan 1, 2017 at 4:53 AM, John Blum <[email protected]
<mailto:[email protected]>> wrote:
Also note, here is an example...
https://github.com/spring-projects/spring-gemfire-examples/tree/master/quickstart/json
<https://github.com/spring-projects/spring-gemfire-examples/tree/master/quickstart/json>
On Sat, Dec 31, 2016 at 3:22 PM, John Blum <[email protected]
<mailto:[email protected]>> wrote:
Dharam-
You should take a look at this...
http://docs.spring.io/spring-data-gemfire/docs/current/reference/html/#bootstrap:region:json
<http://docs.spring.io/spring-data-gemfire/docs/current/reference/html/#bootstrap:region:json>
Also, be aware that if you stick a (JSON) "String" in a Region
as a value (i.e. Region.put(key, stringValue)) then the type
of the value will be a String, not a PDX instance as I assume
you would expect. Geode has no idea whether you are sticking
JSON into a Region or a String.
Additionally, using JSONFormatter is clunky and limiting since
you are now tied to the JSON processing implementation of
JSONFormatter. Likewise, it only knows about JSON Strings
(PdxInstance:fromJSON(:String)) and PDX Instances
(toJSON(:PdxInstance)). What happens if you pass in an
Object? What then?
Under-the-hood, the SDG Region auto-proxy support uses
JSONFormatter, but also knows what to do with a POJO if a
Region.put(key, Object) occurs since that Region is proxied to
store JSON, err... PDX content.
You must have the JSON data stored in Geode as a PdxInstance
to be able to index and query the JSON document.
Hope this helps!
-John
On Sat, Dec 31, 2016 at 8:59 AM, Dharam Thacker
<[email protected] <mailto:[email protected]>>
wrote:
Hi Team,
Wish you all a very happy new year!
Is there any example on json processing with apache geode?
Could you help us with below examples on how region
definition would look like?
_*Example*_:
_*Case1: Primary key <java.lang.String>*_
region.put(String.valueOf(i),
JSONFormatter.fromJSON(obj.toJSONString()));
For above, I believe it should be -->
Region<String,PdxInstance> then how does it look like in
spring data geode xml configuration?
_*Case2: Primary Key <? extends java.lang.Serializable>*_
region.put (new CustomObject() ,
JSONFormatter.fromJSON(obj.toJSONString()));
For above, I believe it should be -->
Region<CustomObject,PdxInstance> then how does it look
like in spring data geode xml configuration?
_*Case3: Is below case valid one and recommended ?*_
@Region
Class JSONRegion {
CustomPrimaryKeyObject primaryKey;
JSONObject jsonObject;
// Constructor + Getter/Setter
}
More is there any limitation/pros-cons if we store JSON
document as value vs schema bound domain java object?
Thanks & Regards,
- Dharam Thacker
--
-John
john.blum10101 (skype)
--
-John
john.blum10101 (skype)
