Friday, June 29, 2018

101 Ways to Process JSON with PeopleCode

... well... maybe not 101 ways, but there are several!

There is a lot of justified buzz around JSON. Many of us want to (or must) generate and parse JSON with PeopleSoft. Does PeopleSoft support JSON? Yes, actually. The Documents module can generate and parse JSON. Unfortunately, many of us find the Documents module's structure too restrictive. The following is a list of several alternatives available to PeopleSoft developers:

  • Documents module
  • Undocumented JSON objects delivered by PeopleTools
  • Java implementation (now included with PeopleTools)
  • JavaScript via Java's ScriptEngineManager

We will skip the first two options as there are many examples and references available on the internet. In this post, we will focus on the last two options in the list: and JavaScript. Our scenario involves generating a JSON object containing a role and a list of the role's permission lists.

PeopleCode can do a lot of things, but it can't do everything. When I find a task unfit for PeopleCode, I reach out to the Java API. PeopleCode has outstanding support for Java. I regularly scan the class and classes directories of PS_HOME, looking for new libraries I can leverage from PeopleCode. One of the files in my App Server's class path is json.jar. As a person interested in JSON, how could I resist inspecting the file's contents? Upon investigation, I realized that json.jar contains the Java JSON implementation. This is good news as I used to have to add this library myself. So how might we use json.jar to generate a JSON file? Here is an example has this really cool fluent design class named JSONStringer. If the PeopleCode editor supported custom formatting, fluent design would be really, really cool. For now, it is just cool. Here is an example of creating the same JSON using the JSONStringer:

What about reading JSON using The following example starts from the JSON string generated by JSONStringer. It is a little ugly because it requires Java Reflection to invoke the JSONObject constructor. On the positive side, though, this example demonstrates Java Class casting in PeopleCode (hat tip to tslater2006 for helping me with Java Class casting in PeopleCode)

What is that you say? Your PeopleTools installation doesn't have the json.jar (or jsimple.jar) files? If you like this approach, then I suggest working with your system administrator to deploy the jar file to your app and/or process scheduler's Java class path

But do we really need a special library to handle JSON? By definition, JSON describes a JavaScript object. Using Java's embedded JavaScript script engine, we have full access to JavaScript. Here is a sample JavaScript file that generates the exact same JSON as the prior two examples:

... and the PeopleCode to invoke this JavaScript:

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