private static DocumentOperationType operationNameToOperationType(String operationName) {
        return switch (operationName) {
            case PUT, ID -> DocumentOperationType.PUT;
            case REMOVE -> DocumentOperationType.REMOVE;
            case UPDATE -> DocumentOperationType.UPDATE;
            default -> throw new IllegalArgumentException("Got " + operationName + " as document operation, only \"put\", " +
                                                          "\"remove\" and \"update\" are supported.");
        };
    }
Parses one item from the stream.

@return whether an item was found
document/src/main/java/com/yahoo/document/json/document/DocumentParser.java