ATG Interview Questions

What is atg Nucleus??

Nucleus is a ATG container for components. It creates and initializes component instances on request. It manages the components scope. It locates the properties file for the component and through that it reaches the class file of the component. Nucleus components are Java Objects each with an associated .properties file which store configuration values.

What is MANIFEST file?

Applications often depend on other modules, these dependencies are declared in this file.The file name is MANIFEST.MF and resides in the META_INF directory. It specifies ATG-Class-Path,ATG-Required, ATG-Config-Path etc.

How a component is instantiated ??

One can start or stop components manually using an ACC.

OR.

We can instruct nucleus to start a component during server startup, this is done by modifying the “Initial.properties” file.Add the component name to the “initialServices” property inside the Initial.properties file.

Differentiate Global,Request & session scopes.

Global: components are accessible from all other components.Not available across ATG servers, each server has its own copy of global scoped component.

Session: means every user of the application gets a separate copy of the component, and component exists for duration of the user’s session.

Request : A component is called in for returning the values of a search, so each time a search is triggered an object instantiation happens and its gone when the result page is closed.Which means the scope of the search component is request.Eg:-formhandlers normally have a request scope.

What is a context root?

Is a URL mounting point of the web application. It decides what URL site site visitors will enter to get to the site. Eg: http://www.atg.com/”context-root” “context-root” is specified in the “application.xml” file in the “j2ee-apps” folder.,

What is ATG Dynamo? What is ATG Framework?

ATG Dynamo or Dynamo Application Server(DAS) is a J2EE application server from Art Technology Group. Atg framework is a Web Application framework for building web applications. ATG dynamo implements the ATG framework. The application framework can also be run on all major J2EE application servers (JBoss, WebLogic, WebSphere etc...).

What is the scope of Dynamo Components?

There are three different types of scopes for ATG components namely

• request
• session
• Global

Global is the default scope

What is Nucleus?

Nucleus is ATG`s open Object Application Framework. ATG 7 is said to be a component-centric development platform. The ATG 7 Web applications are nothing but individual JavaBean components assembled together. These JavaBean components are configured and linked together by .properties files within Nucleus.

In Nucleus, each service is packaged as a JavaBean or set of JavaBeans. These JavaBeans are configured individually and mounted into a namespace. The beans then interconnect with the beans representing other services. Nucleus is responsible for interpreting the component configurations and the management of the component namespace. Dynamo uses the Nucleus framework to organize components into a hierarchical structure (similar to a directory structure). Each Nucleus service has a unique Nucleus name. For example, the default javax.sql.DataSource component is located at /atg/dynamo/service/jdbc/JTDataSource

Nucleus is the core of the entire ATG system. It creates and configures Nucleus components (also called beans and JavaBeans) and organizes them into a hierarchical namespace, essentially giving them a place to live so they can be referenced by other components. By reading the .properties files associated with each component, Its Nucleus which figures out that which components are to be used in an application ,initializes them to their default values and how decides about how they connect to each other. This model makes it easier for the developers to build ATG applications by configuring and using the pre-built components instead of writing a lot of Java code from scratch.

What is ATG Repository?

ATG Repository refers to the ATG`s way of accessing the Database through programs. It is somewhat similar to what Hibernate offers, Seperating the Application Logic from that of Database. So Atg repository provides a fine grained abstraction between the application logic and Database. Thus it supports the ATG`s Data Anywhere paradigm, the application logic created by developers to interact with data need not change for any change in the source of that data. ATG repository architecture ensures that the source of the data is hidden behind the Dynamo Repository abstraction. It would be easy to change from a relational data source to another or to an LDAP directory since none of the application logic would need to change. Once data is retrieved from a data source it is transformed into an object-oriented representation. Manipulation of the data can then be done using simple getPropertyValue and setPropertyValue methods. The Repository API ties in closely with ATG’s targeting APIs, so you can retrieve items from the repository based on a variety of targeting rules, as well as retrieving specific identified items.