How to set Java - SnakeYaml Dumperoptions to leave out Quotations and '|'?

Question

I am using Snakeyaml in Java to dump a Yaml-File which is later parsed by another Application.

The output-Yaml has to look like this:

aKey: 1234
anotherKey: a string
thirdKey:
  4321:
    - some script code passed as a string
    - a second line of code passed as a string

So far, the closest i have come is by setting the dumper - options like this:

DumperOptions options = new DumperOptions();
options.setIndent(2);
options.setPrettyFlow(true);
options.setDefaultFlowStyle(DumperOptions.FlowStyle.BLOCK);
[...]
Map<String, Object> data = new LinkedHashMap<>();
Map<Integer, Object> thirdKey= new LinkedHashMap<>();
data.put("aKey", 1234);
data.put("anotherKey", "aString");
StringBuilder extended = new StringBuilder();
extended.append("- some script code passed as a string\n- a second line of code passed as a string\n");
String result = extended.toString();
thirdKey.put(4321, result);
data.put("thirdKey", thirdKey);
yaml.dump(data, writer);

The output, however, is like this:

aKey: 1234
anotherKey: a string
thirdKey:
  4321: |
    - some script code passed as a string
    - a second line of code passed as a string

The mere | is what is separating me from achieving my final goal.

Is there any way to set the dumperoptions to break the lines like this without inserting a | symbol?

Answer 1

The problem is that you generate the list markers - as part of your content. They are not! They are part of the YAML syntax.

Since what you want in YAML is a sequence (YAML term for a list), you have to put a list into your structure:

thirdKey.put(4321, Arrays.asList(
  "some script code passed as a string",
  "a second line of code passed as a string"));