JETT Template engine is not supporting the List of collections instead it supports List of Java Entity classes

Question

I was using JETT Template engine for report generation. The JETT Template engine supports the below format of input.

Map<String, Object> beans = new HashMap<String, Object>();
ValueObject beanName = new ValueObject();
beanName.setProperty("Hello, World!");
beans.put("beanName", beanName);

I have tried the above and it's working fine. But in this case the type Object is referring to Java Entity classes. Here I wanted to generate a report using JETT template Engine without using Java Entity classes. Instead I have created a collection object directly from a JSON string. My Collection object looks like:

List<List<Map<String, String>>> packageList = new ArrayList<>();

Will the JETT template engine support this format? How can I refer to the keys in the map in the JETT template?

Answer 1

JETT will support this object as long as you store it in the beans Map like you would with a Java entity object.

beans.put("myPackageList", packageList);

Once it's there, you can refer to the "myPackageList" variable in your JETT tags or expression.

You will likely want to iterate over the two Lists you have, which will likely be done with some forEach tags.

Once you've reached the stage where you're manipulating the Map object (let's say it's stored in a packageInfo variable), you can do a forEach on the keys with packageInfo.getKeys(), and for each of the keys, get the value in the map with packageInfo.get(key). For more details on the syntax of the scripting language used in JETT, you can refer to JEXL.