Listify/Lambdas/Lists/src/main/java/InputUtils.java

import java.util.Map;

public class InputUtils {
    public static String getCognitoIDFromBody(Map<String, Object> inputMap) {
        System.out.println(inputMap.keySet());
        System.out.println(inputMap.entrySet());
        Map<String, Object> contextMap;
        if ((inputMap.get("context") != null) && (inputMap.get("context") instanceof Map<?, ?>)) {
            contextMap = ((Map<String, Object>) inputMap.get("context"));
        } else {
            throw new IllegalArgumentException("The key \"context\" must exist and be a map");
        }
        System.out.println(inputMap.get("context"));
        System.out.println(contextMap.get("sub"));
        return contextMap.get("sub").toString();
    }

    public static Map<String, Object> getBody(Map<String, Object> inputMap) {
        return getMap(inputMap, "body");
    }

    public static Map<String, Object> getMap(Map<String, Object> parentMap, String childKey) {
        if ((parentMap.get(childKey) != null) && (parentMap.get(childKey) instanceof Map<?, ?>)) {
            return ((Map<String, Object>) parentMap.get(childKey));
        }
        throw new IllegalArgumentException("The key \"" + childKey + "\" must exist and be a map");
    }
}