.java

Parser parser = Parser.newBuilder().build();

// extracts id into mid, internalDate into date, payload/headers into headers, returns the new object
// Query query = "(mid: #{'id'}, date: #{'internalDate'}, headers: #{'payload'}{'headers'})";

// alternative version to define it
Query query = parser.newQueryBuilder().asDictionary()
        .putEntry("mid").stream(0).dictionary("id").endEntry()
        .putEntry("date").stream(0).dictionary("internalDate").endEntry()
        .putEntry("headers").stream(0).dictionary("payload").dictionary("headers").endEntry()
        .endDictionary().build();

Input input = Input.fromByteArray(...);
Value value = parser.read(input, query);

Dictionary dictionary = value.dictionary();

Value idValue = dictionary.get("mid");
long id = idValue.number().longValue(); // Java Number type

Value dateValue = dictionary.get("date");
Instant date = dateValue.tag(); // Date extension type in CBOR

Value headersValue = dictionary.get("headers");
Dictionary headers = headersValue.dictionary(); // Just another directory