How to read a list from a YAMLConfigutation

Question

I have a YAML file that looks like this:

foo:
  bar:
    - entry1: 1
      entry2: a
    - entry1: 2
      entry2: b

(Where the actual list is much longer.) I'm reading this file using Apache Configuration2's YAMLConfiguration. I can see the data in the internal data structures used in Apache Configuration2, but I can't figure out how to get this list out. I actually have a class that matches the structure of the list elements, which is what I'd really like to read into:

class MyListEntry {
    public int entry1;
    public String entry2;
}

How can I get the data YAMLConfiguration into a List<MyListEntry>?

score 0 · Accepted Answer · answered Oct 21 '21 at 23:47

Here's the solution I found (note this works for any HierarchicalConfiguration, not just YAMLConfiguration)

// this will return a list of List<HierarchicalConfiguration<ImmutableNode>>, one entry for each element of the list
var subConfigList = hierarchicalConfig.configurationsAt("foo.bar");

List<MyListEntry> myListEntries = new ArrayList<>(subConfigList.size());
// iterate over the subconfigs and pull out the specific values of interest
for(var subConfig : subconfigs) {
    MyListEntry myListEntry = new MyListEntry();
    myListEntry.entry1 = subConfig.getInt("entry1");
    myListEntry.entry2 = subConfig.getString("entry2");
    myListEntries.add(myListEntry);    
}

How to read a list from a YAMLConfigutation

1 Answers1