ActiveAndroid で、データ挿入の際にどのように行えばよいかわからず悩んでおります。

book.title = "Book"; 
book.save(); 

上記のように挿入することは分かったのですが、モデルにデータを挿入する際、どのように行えばよいか思案しています。

よろしくお願いします。

  public static void jsonParse() {

    new Delete().from(Book.class).execute();
    ActiveAndroid.beginTransaction();

    try {
        AndroidTestActivity.mContext = app.getContext();

        AssetManager assetManager = mContext.getAssets();

        InputStream inputStream = assetManager.open(FILE_NAMES);

        JsonReader jsonReader = new JsonReader(new InputStreamReader(inputStream));
        Gson gson = new Gson();
        JsonParser parser = new JsonParser();
        JsonArray jArray = parser.parse(jsonReader).getAsJsonArray();

        Book book = new Book();
        /** ここでどのように挿入すればよいか */
        book.title = 
        book.author = 
        book.publisher = 
        book.releaseDate = 

        book.save();

    } catch (IOException e) {
        e.printStackTrace();
    }
    finally {
        ActiveAndroid.setTransactionSuccessful();
    }
    ActiveAndroid.endTransaction();
}

Book.java

   @Table(name = "Book")
        public class Book extends Model {
            private static final String TAG = Book.class.getSimpleName();

            @Column(name = "title")
            public String title;

            @Column(name = "author")
            public String author;

            @Column(name = "publisher")
            public String publisher;

            @Column(name = "release_date")
            public String releaseDate;

            public Book() {
                super();
            }
            public Book(String title, String author, String publisher, String date) {
                super();
                this.title = title;
                this.author = author;
                this.publisher = publisher;
                this.releaseDate = date;
            }

            public static Book fromJson(JSONObject jsonObject){
                Book b = new Book();

                try{
                    b.title = jsonObject.getString("title");
                    b.author = jsonObject.getString("author");
                    b.publisher = jsonObject.getString("publisher");
                    b.releaseDate = jsonObject.getString("release_date");
                    b.save();
                }catch (JSONException e) {
                    e.printStackTrace();
                    return null;
                }
                //return new object
                return b;
            }
        }