Data Flow fails to parse JSON with page list structure
Data Flow fails to parse JSON with page list structure
We have a file data set, and we are running one Data Flow to parse JSON record via data transform rule to deserialize JSON string to Pega data object. But we are running into the following error, it only impact JSON string with list structure (Pega Page List):
com.pega.dsm.dnode.api.dataflow.StageException: Exception in stage: data_set_name Caused by: com.pega.dsm.dnode.api.ExceptionWithInputRecord: com.pega.pegarules.pub.PRRuntimeException: LegacyModelAspectInvokableRuleContainer.invoke-Exception Encountered a :java.lang.UnsupportedOperationException
step to produce:
1. Configure a file dataset to retrieve data from JSON file which contain list data structure;
2. Create dataflow rule to add data transform shape to invoke deserialization datafranform rule to parse JSON to pega data object.
3. Run this dataflow and it failed as error showed above.
Note: dataflow runs successfully on JSON data without list structure.
HCA Healthcare
US
@SHIZ1 The error occurs because the Data Flow cannot properly handle JSON strings that contain a list (Page List) structure when using a Data Transform to deserialize them. This usually happens when the Data Transform tries to map a complex list directly, which is not supported out of the box in some scenarios—especially with legacy or unsupported structures. To fix this, first ensure your JSON schema matches the Pega data model exactly, including the page list property being defined correctly as a
Page Listwith the right class. Instead of using a Data Transform directly for deserialization, try using a JSON Data Set or a custom activity withpxConvertStringToPageorJSONUtilmethods to parse the string and handle the list properly. Also, consider preprocessing the file to extract and flatten the list entries if needed. Validate the data step-by-step by running it manually in clipboard to catch any mapping issues.