Method beforeValue

src/main/java/com/google/gson/stream/JsonWriter.java:520–552

Inserts any necessary separators and whitespace before a literal value, inline array, or inline object. Also adjusts the stack to expect either a closing bracket or another element. @param root true if the value is a new array or object, the two values permitted as top-level elements.

(boolean root)

   *     permitted as top-level elements.
   */
  private void beforeValue(boolean root) throws IOException {
    switch (peek()) {
    case EMPTY_DOCUMENT: // first in document
      if (!lenient && !root) {
        throw new IllegalStateException(
            "JSON must start with an array or an object.");
      }
      replaceTop(JsonScope.NONEMPTY_DOCUMENT);
      break;

    case EMPTY_ARRAY: // first in array
      replaceTop(JsonScope.NONEMPTY_ARRAY);
      newline();
      break;

    case NONEMPTY_ARRAY: // another in array
      out.append(',');
      newline();
      break;

    case DANGLING_NAME: // value for name
      out.append(separator);
      replaceTop(JsonScope.NONEMPTY_OBJECT);
      break;

    case NONEMPTY_DOCUMENT:
        throw new IllegalStateException(
            "JSON must have only one top-level value.");

    default:
      throw new IllegalStateException("Nesting problem: " + stack);
    }
  }
}