c# generate barcode from string PART II in Java

Generate Quick Response Code in Java PART II

PART II
QR Code Generator In Java
Using Barcode creator for Java Control to generate, create Denso QR Bar Code image in Java applications.
www.OnBarcode.com
QR Code 2d Barcode Decoder In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Server-Side Component Models
Barcode Generation In Java
Using Barcode maker for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
Code-39 Printer In Java
Using Barcode creator for Java Control to generate, create Code 3/9 image in Java applications.
www.OnBarcode.com
We ve now seen how EJB s component types allow us to write less, allowing the container to equip us with services and other runtime support. In this section we ll more fully address the available server-side models: session beans and message-driven beans. EJB s basic building block for implementing business logic taskflow is the session bean. Taskflow refers to all the steps required to service a request such as making a doctor s appointment or renting a video. Session beans frequently manage the interactions within persistent data entity beans describing how they work together to accomplish a specific goal. Session beans are divided into three basic types: stateless, stateful, and singleton. A stateless session bean ( 5) is a collection of related services, each represented by a business method; the bean maintains no conversational state from one method invocation to the next. When you make a request upon a stateless session bean, the container executes the target method and returns the result without knowing or caring what other requests have gone before or might follow. Think of a stateless session bean as a set of procedures or batch programs that execute based on some parameters and return a result. A stateful session bean ( 6) is an extension of the client application. It performs tasks on behalf of the client and maintains state related to that client. This is called conversational state because it represents a continuing set of exchanges between the stateful session bean (SFSB) and the client. Methods invoked on a stateful session bean can write and read data to and from this conversational state, which is shared among all methods in the bean. A singleton session bean ( 7) is backed by only one target: an instance of the bean implementation class. All business requests are serviced by the same backing object, so state is shared throughout the application. This is especially useful for performing system-wide initialization or governing a process from a sole authority.
Creating Barcode In Java
Using Barcode creation for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
Encode PDF-417 2d Barcode In Java
Using Barcode drawer for Java Control to generate, create PDF417 image in Java applications.
www.OnBarcode.com
Message-driven beans ( 8) act as listeners for incoming events. They are not invoked directly by the client, and they do not provide any return value. As we ll see, these may make a powerful utility for wiring together various pieces of an application.
DataMatrix Maker In Java
Using Barcode generation for Java Control to generate, create Data Matrix 2d barcode image in Java applications.
www.OnBarcode.com
Code 11 Creation In Java
Using Barcode creator for Java Control to generate, create USD - 8 image in Java applications.
www.OnBarcode.com
The Stateless Session Bean
Read QR Code In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
Paint Denso QR Bar Code In C#.NET
Using Barcode creator for .NET Control to generate, create QR Code ISO/IEC18004 image in Visual Studio .NET applications.
www.OnBarcode.com
The stateless session bean is designed for efficiency and simplicity. Central to its design is the absence of conversational state, which is a topic worth exploring a bit further before delving into SLSB mechanics. When we say conversational state, we refer to information exchanged and remembered within the context of a series of requests between the Client (caller) and EJB (service). We can illustrate this simply:
Matrix 2D Barcode Drawer In Visual Studio .NET
Using Barcode maker for VS .NET Control to generate, create 2D image in VS .NET applications.
www.OnBarcode.com
Decode GS1-128 In Visual C#
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Mike: Hi, my name is Mike. Service: Hello, Mike. Mike: Do you know my name Service: Yes, your name is Mike.
EAN13 Generator In VS .NET
Using Barcode printer for Reporting Service Control to generate, create European Article Number 13 image in Reporting Service applications.
www.OnBarcode.com
Barcode Drawer In VB.NET
Using Barcode generator for Visual Studio .NET Control to generate, create Barcode image in .NET applications.
www.OnBarcode.com
Here, the state variable holding the name of the client is stored for the duration of the conversation. Stateless session beans are incapable of handling this exchange correctly; each invocation upon a SLSB proxy operates independently from those both before and after (see Figure 5-1). In fact, its underlying bean instances may be swapped interchangeably between requests. Stateless session beans are EJB s answer to traditional transaction-processing applications, which are executed using a procedure call. The procedure runs from beginning to end, finally returning the result. Once the invocation completes, nothing about the data that was manipulated or the details of the request is available. When finished servicing a method invocation, an SLSB instance may be reused as the target for a new request. In short, stateless session beans are engineered to be lightweight and fast at the expense of conversational state. A much better usage of a SLSB looks like:
Barcode Reader In C#.NET
Using Barcode Control SDK for Visual Studio .NET Control to generate, create, read, scan barcode image in .NET framework applications.
www.OnBarcode.com
Draw Barcode In Java
Using Barcode drawer for Android Control to generate, create Barcode image in Android applications.
www.OnBarcode.com
Mike: SLSB: Mike: SLSB: Mike: SLSB: How much money is in savings account B $100. Please transfer $200 from checking account A to savings account B. OK, done. How much money is in savings account B $300.
Making Barcode In Visual Studio .NET
Using Barcode maker for VS .NET Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
QR Printer In Visual Studio .NET
Using Barcode maker for Reporting Service Control to generate, create QR Code ISO/IEC18004 image in Reporting Service applications.
www.OnBarcode.com
Here Mike has supplied the SLSB with all the information it needs to process a request within the request itself.
Drawing Code-128 In None
Using Barcode printer for Word Control to generate, create Code 128 Code Set B image in Office Word applications.
www.OnBarcode.com
Barcode Creator In None
Using Barcode maker for Office Word Control to generate, create Barcode image in Office Word applications.
www.OnBarcode.com
Bypassing conversational state doesn t mean that a stateless session bean can t have instance variables or maintain any kind of internal state. Nothing prevents you from keeping a variable that tracks the number of times a bean instance has been called or a variable that saves data for debugging. However, it is important to remember that this state may never be visible to a client. The caller of an SLSB can t assume that the same bean instance will service all of its requests. Instance variables may have different values in different bean instances, so their state is likely to appear to change randomly as stateless session beans are swapped from one client to another. Therefore, anything you reference in instance variables should be generic and not leaked out through the API. For example, an SLSB might reasonably record debugging messages that might be the only way to figure out what is happening on a large server with many bean instances. The client doesn t know or care where debugging output is going. However, it would clearly be inappropriate for a stateless bean to remember that it was in the process of making a reservation for Madame X; the next time it is called, it may be servicing another client entirely. An SLSB used improperly might act a little like this:
Mike: SLSB: Mike: SLSB: Hi, my name is Mike. Hello, Mike. Do you know my name Yes, your name is Jason.
Copyright © OnBarcode.com . All rights reserved.