I am building a Java application that uses a database and I’m using a DAO design pattern: in my code, all objects classes have an associated DAO class that implements an interface with get, save and update methods. For instance, for a User object, I will have the following class (ConnectionDB implements…
Tag: dao
Dao Room database. How to SUM all the amounts and view it as a TextView?
I am creating a simple expence tracker. I can add items to the database and view them in a recyclerview. But when I try to SUM all values from a column, it only return 0 instead of the sum of all the values. First of all, here’s the column which values I am trying to sum together. And here is
Creating new instance of concrete implementation in interface – is this an antipattern?
Let’s say I have the interface AuthorDao with two different implementation classes for example MyAuthorDaoImpl1 and MyAuthorDaoImpl2. In my interface AuthorDao I have some basic crud methods and one extra method which is static for getting a new instance of MyAuthorDaoImpl1. It looks like this: Question…
Understanding Dao-pattern, can it be used for retrieving data from cache?
I read about DAO-pattern in the official documentation and it’s not quite clear if it can be used for retrieving data from cache? Formally speaking, DAO is an additional abstraction layer between clients and mechanism the data is being retrieved from somewhere. So, if data resides in cache, I suppose we…
passing value to a jsp page from a java class using DAO
I wanted to pass the value retrieved on a java class to a page.I am using DAO classes. I have retrieved the values from the database and stored them on String variables.Now I want to set them to the text boxes in my view.jsp page.I am new to this area,can anyone help me out?? View.jsp is as and My Activity
Where is the best place to begin transaction using Hibernate in a tired web application with Struts 2?
I got this Java web application which uses Struts 2 and Hibernate. In the most upper layer comprises of the Struts 2 action classes. Then there are my business logic classes which are responsible for the logic of the application. Finally there is a DAO layer (called Database Bridge) which is responsible for c…