barcode in vb.net 2008 Why Use a Data Access Object in Java

Painting Quick Response Code in Java Why Use a Data Access Object

Why Use a Data Access Object
Denso QR Bar Code Decoder In Java
Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications.
Creating QR In Java
Using Barcode creation for Java Control to generate, create QR Code JIS X 0510 image in Java applications.
The data access object (DAO) pattern separates the interface to a system resource from the underlying code used to access that resource. This allows the benefit of database vendor independence and the ability to represent XML data sources as objects. Each enterprise bean that accesses a persistent data resource can have an associated DAO class, which defines an abstract API of operations on the resource. This abstract API will make no reference to the resource implementation. The DAO needs to know only how to load itself from a persistent store based on some identity information (such as a primary key) and how to store itself back to the persistent store. Therefore, an enterprise bean uses data it obtains from the DAO, defers the persistence responsibilities to the DAO, and can concentrate entirely on implementing business methods.
Quick Response Code Recognizer In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
Bar Code Generation In Java
Using Barcode maker for Java Control to generate, create bar code image in Java applications.
State the Bene ts of Bean Pooling in an EJB Container
Barcode Scanner In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
Paint QR Code ISO/IEC18004 In C#.NET
Using Barcode drawer for .NET framework Control to generate, create QR Code image in .NET applications.
A DAO provides resource functionality for a particular resource, implemented for a particular persistence mechanism. For example, a class can be created to encapsulate the database resource access for both single as well as multiple rows. The benefits are independence achieved at a small cost (the development required to build the DAO) that ultimately may save development time. For CMP entity beans, the EJB container automatically services all persistent storage access; therefore, applications using CMP entity beans do not need a DAO layer, since the application server transparently provides this functionality. However, DAOs may still be useful when an application has a combination of CMP for entity beans and BMP for session beans and/or servlets. DAOs add a layer of objects between the data client and the data source that requires extra effort to be designed and implemented. However, the benefit realized by choosing this approach makes up for the added effort. When a factory strategy is used, the hierarchy of concrete factories and concrete products produced by the factories requires additional design and implementation.
Printing QR Code ISO/IEC18004 In VS .NET
Using Barcode drawer for ASP.NET Control to generate, create QR Code JIS X 0510 image in ASP.NET applications.
QR Code JIS X 0510 Generation In .NET
Using Barcode generator for .NET Control to generate, create Denso QR Bar Code image in .NET framework applications.
CERTIFICATION OBJECTIVE 7.09
QR Code Encoder In Visual Basic .NET
Using Barcode generation for VS .NET Control to generate, create QR Code JIS X 0510 image in Visual Studio .NET applications.
European Article Number 13 Printer In Java
Using Barcode generation for Java Control to generate, create GS1 - 13 image in Java applications.
State the Benef its of Bean Pooling in an EJB Container
Creating Bar Code In Java
Using Barcode drawer for Java Control to generate, create bar code image in Java applications.
EAN 128 Generator In Java
Using Barcode drawer for Java Control to generate, create USS-128 image in Java applications.
Here, we review the concept of pooling resources. We explain how the EJB container uses this concept for EJBs.
USS-93 Drawer In Java
Using Barcode creation for Java Control to generate, create USS-93 image in Java applications.
Decoding Data Matrix 2d Barcode In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
Bean Pooling in the EJB Container
Bar Code Encoder In Visual Basic .NET
Using Barcode generation for Visual Studio .NET Control to generate, create barcode image in Visual Studio .NET applications.
ECC200 Decoder In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
Given that the EJB container cannot handle an unlimited number of EJBs, the classic concept of pooling is used to share the resources among multiple users. When the EJB is deployed, the deployment descriptor specifies the number of instances to pool and reuse. The cost of creating and destroying an EJBObject can be high. The application server manages a pool of EJBs that can be used throughout the application. This pool allows the application server to handle more requests, since the server does not have to spend time creating and destroying EJBObjects. Note that stateful session beans cannot be a part of this bean pool.
Printing ECC200 In VS .NET
Using Barcode maker for Reporting Service Control to generate, create Data Matrix 2d barcode image in Reporting Service applications.
Encoding Code 128C In Visual Studio .NET
Using Barcode creation for ASP.NET Control to generate, create Code128 image in ASP.NET applications.
7: Enterprise JavaBeans and the EJB Container Model
UPC-A Encoder In None
Using Barcode drawer for Office Word Control to generate, create UPC Code image in Office Word applications.
Code 128 Code Set C Creator In C#.NET
Using Barcode creation for VS .NET Control to generate, create Code 128 image in .NET framework applications.
Benefits of Bean Pooling in an EJB Container
Bean pooling is similar to connection pooling, a technique that was pioneered by the DBMS vendors to allow multiple clients to share a cached set of connections that provide access to a database resource. Bean pooling is used in Java Platform EE for stateless session beans. To implement bean pooling, the application server, as part of a startup process, must create a pool manager object to control access to the stateless session beans. The client asks the pool manager to allocate a bean. If a bean is available in the pool, it is made available to the client immediately; otherwise, a bean is created. When a client no longer needs the bean, it returns the bean to the pool manager for reuse. This strategy allows beans to be quickly allocated to clients, avoiding the expense of setup and initialization.
CERTIFICATION OBJECTIVE 7.10
State the Benef its of Passivation in an EJB container
Here, we review the benefits of the passivation/activation technique that is employed by an EJB container.
Passivation/Activation
Passivation/activation is a technique that the EJB container can choose to temporarily serialize a bean and store it to the application server s file system or other persistent store is such a way to allow it to recreate the bean and its state at a later time. This technique allows the application to optimally manage resources.
Copyright © OnBarcode.com . All rights reserved.