Setting Object variables from Tasklist or REST API

Camunda 7 Topics
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1

I am using Camunda Platform 7.19.0. I am trying to set an Object variable from Task list or from the REST API. For example, when I try to create an ArrayList variable from like this

PUT /process-instance/aProcessInstanceId/variables/aVarName
{
  "value" : "[1,2]",
  "type" : "Object",
  "valueInfo" : {
    "objectTypeName": "java.util.ArrayList",
    "serializationDataFormat": "application/xml"
  }
}

I get this error in cockpit

image
image743×456 19.1 KB

I also tried to set it in Tasklist like this but I am not sure what to type here

set_variable
set_variable1130×650 24 KB

I have already added camunda-engine-plugin-spin in Gradle dependencies. I have checked the documentation about serialization/deserialization, but I am still confused about how to set Object variables.
Any help would be appreciated.

Thanks.

2

@cambarantama Refer this page:

3

Does the object type name have to be a POJO? I am trying something like an ArrayList like this

{
  "value" : "[\"item1\", \"item2\", \"item3\"]",
  "type" : "Object",
  "valueInfo" : {
    "objectTypeName": "java.util.ArrayList",
    "serializationDataFormat": "application/json"
 }

but it deserialization keeps failing.

4

From the docs: To retrieve the serialized form of a variable, use the deserializeValues=false GET parameter.

@cambarantama , In previous example you’ve used xml as serializationDataFormat and the below example you’re using JSON.

Which serializationDataFormat you’re actually looking for?

Here are the supported variable types:

5

@ aravindhrs
I am looking for serializationDataFormat of type application/json.
I was attempting to set a variable such as this

{
  "value" : "[\"item1\", \"item2\", \"item3\"]",
  "type" : "Object",
  "valueInfo" : {
    "objectTypeName": "java.util.ArrayList",
    "serializationDataFormat": "application/json"
 }

Basically, how can I set a variable of type Object either from Tasklist or the REST API without using a predefined POJO?

6

Hi @cambarantama

Try the following

{
  "value": ["item1", "item2", "item3"],
  "type": "Object",
  "valueInfo": {
    "objectTypeName": "java.util.ArrayList",
    "serializationDataFormat": "application/json"
  }
}
7

Hi @hassang
With that, I get this error:
{"type":"InvalidRequestException","message":"Cannot put process instance variable myArrayList: Must provide 'null' or String value for value of SerializableValue type 'Object'.","code":null}