JSON Stream Processing with PeopleCode

Our Integration Tools courses emphasize the importance of utilizing PeopleSoft's native JSON support to parse and process JSON. This feature provides excellent functionality for most scenarios, as PeopleSoft's native JsonObject and JsonArray offer fast and efficient JSON processing. They are particularly useful for generating small integration responses or handling tasks like JWT (JSON Web Token) generation.

It's important to note that PeopleSoft's native JSON definitions employ a DOM-based parser, which builds an in-memory JSON structure. While this is effective in many cases, it does require your server to have enough memory to accommodate the entire JSON document without impacting its normal workload. Large files, therefore, can be problematic.

Stream-based parsing provides an alternative approach. With a stream-based parser, events are emitted as they occur, enabling immediate processing of data identified by these events. Once processed, the parser discards the data and proceeds to the next event. For instance, let's consider a scenario where you have a massive array of users. A DOM parser would load the entire array into memory, whereas a stream-based parser would only load one user at a time, allowing you to process the user and then discard it. Stream-based parsers are often more efficient in terms of resource utilization, as they process and discard data right away instead of constructing a traversable in-memory document.

Although PeopleCode itself doesn't include a stream-based parser, it does include the Java Jakarta stream-based JSON parser, which we can leverage through PeopleSoft's built-in Java support. Let me share an example with you. For testing purposes, I obtained a sample JSON file from https://jsonplaceholder.typicode.com/users. This file is small and perfect for testing. I then incorporated the following PeopleCode into an App Engine step, which you can run locally through App Designer:

REM ** JavaDoc: https://jakarta.ee/specifications/jsonp/2.0/apidocs/jakarta.json/jakarta/json/stream/jsonparser;
REM ** Data: https://jsonplaceholder.typicode.com/users;
Local JavaObject &Json = GetJavaClass("jakarta.json.Json");
Local JavaObject &reader = CreateJavaObject("java.io.FileReader", "C:\temp\users.json");
Local JavaObject &parser = &Json.createParser(&reader);

Local string &email;

While (&parser.hasNext())
   Local JavaObject &next = &parser.next();
   
   If (&next.equals(&next.START_OBJECT)) Then
      
      Local JavaObject &user = &parser.getObject();
      
      REM ** do something with the object;
      &email = &user.getString("email");
      MessageBox(0, "", 0, 0, "email: %1", &email);
   End-If;
End-While;

Here is some sample output generated by this short App Engine program:

email: Sincere@april.biz (0,0)
 Message Set Number: 0
 Message Number: 0
 Message Reason: email: Sincere@april.biz (0,0) (0,0)

email: Shanna@melissa.tv (0,0)
 Message Set Number: 0
 Message Number: 0
 Message Reason: email: Shanna@melissa.tv (0,0) (0,0)

email: Nathan@yesenia.net (0,0)
 Message Set Number: 0
 Message Number: 0
 Message Reason: email: Nathan@yesenia.net (0,0) (0,0)

email: Julianne.OConner@kory.org (0,0)
 Message Set Number: 0
 Message Number: 0
 Message Reason: email: Julianne.OConner@kory.org (0,0) (0,0)

Are you interested in learning more about PeopleSoft Integration, PeopleTools, Or PeopleCode? If so, check out our subscriptions, on-demand, and upcoming course schedule. We would love to have you join us!