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Component Examples
The section contains the following topics:
How to Build and Run the Examples
Package examples.axiom Description
Package examples.workflow Description
Package examples.businesspolicy
Package examples.businesspolicy Description
ItemPriceCalculationPolicy and BusinessPolicy
Package examples.passbyvalue Description
Getting and Setting Attributes Using pass-by-value
How to Build and Run the Examples
To become better acquainted with the workings of an EJB-based application built using our WebLogic Commerce Server (WLCS), follow these examples.
Note: To build and run any of these examples, you must have the following in your CLASSPATH:
The fastest way to run any of the examples is by using the scripts provided in ...\bin\win32\*.bat or ..\bin\solaris2\*.sh (Found under the WLCS installation directory)
Foundation and Axiom
This example demonstrates the core technology: Belongings, Entity Beans, Collections and RemoteIterators.
Package examples.axiom
The Axiom example shows the use of WLCS Axiom package of WebLogic Commerce Server.
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Shows how to use the WLCS components Axiom package. |
Package examples.axiom Description
The Axiom example shows the use of the WLCS components Axiom package.
This example demonstrates:
Belongings and EJBs
The Axiom package contains light weight components known as belongings, as well as Entity and Session EJB components. Belongings can be aggregated to other components by value. EJBs are used alone or aggregated to other components by reference or value.
The Abstract Factory Pattern
All WebLogic Commerce Server use the abstract factory pattern. The principle is very simple: Don't use new() to create an object, instead, you use Home.create(). The Abstract factory pattern is implemented as the "Home" for EJBs and as a Java class with static methods for Belongings.
Axiom Example
The example application performs the following steps:
To get the most out of this example, first read through AxiomExample.java on our web site. Then you can build it and run it.
Note: Be sure to set your CLASSPATH as described in How to Build and Run the Examples.
Workflow
Workfow, eBusinessSession, and eBusinessSessionManager components. The Workflow maintains state for the session and guides the user through the process.
Package examples.workflow
Shows the use of WLCS Workflow components.
This example demonstrates:
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Workflow example. |
Package examples.workflow Description
Shows the use of the WLCS Workflow components.
This example demonstrates:
This example shows the use of a WLCS component that has a workflow associated to it. The workflow states and transitions are modeled with Rational Rose. For this examples, we'll use the EBusinessSession Component. This component has a workflow that guides it through the different stages of an online e-business session. If you look at the Rose model file for the ebusiness.session package, you will find that EBusinessSessionWorkflow has a state diagram associated to it. The workflow logic can be implemented in any way you want; however, WLCS provides a reference implementation. For the reference implementation, for each component with the BSC.Workflow stereotype, all the states and transitions in the Rose model are generated into a complete state machine by the SmartGenerator, so you can use it immediately, without any hand-coding of the workflow states or transitions.
In this example, we also use the EBusinessSessionManager and show how a "manager" session bean can simplify the usage of an entity bean
Workflow Example
The workflow example application performs the following steps:
To get the most out of this example, first read through WorkflowExample.java on our web site then you can build it and run it.
Note: Be sure to set your CLASSPATH as described in How to Build and Run the Examples.
BusinessPolicy
Pluggable Methods, Strategy Pattern, or Individual Instance Method. No matter what you call it, it is a powerful design tool. This example demonstrates how ConfigurableEntity beans and BusinessPolicy work together to create very flexible solutions.
Package examples.businesspolicy
BusinessPolicy Example shows the use of WLCS WebLogic BusinessPolicy Components.
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This class is a custom item pricing calculation policy. |
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This example demonstrates the concept of "Pluggable Methods", better known as policies. |
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This class is a custom item pricing calculation policy. |
Package examples.businesspolicy Description
The BusinessPolicy example shows the use of the WLCS BusinessPolicy components.
This example demonstrates:
ItemPriceCalculationPolicy and BusinessPolicy
This example shows the use of theory.smart.ebusiness.item.ItemPriceCalculationPolicy which is an extension to theory.smart.foundation.BusinessPolicy. A BusinessPolicy consists of rules and regulations, specific to your business. These rules can be encapsulated into a component and then added to a Component such as an Item.
This example demonstrates the concept of "Pluggable Methods", better known as policies. When you create your components, you will realize that many times you want to alter the component behaviour based on external conditions that you can not evaluate at development time. Reusability, extensibility and rapid development and enhancement are typical problems that can be solved using policies. BusinessPolicy is the WLCS implementation of the Policy and Strategy design patterns. Using this concepts allows you to replace the default policy at runtime. The policy is stored as a property for the item.
In this example we will use an item component. The item component has a pricing policy. The item's price is calculated based on a given quantity and the pricing policy. You can replace the pricing policy to alter the way the price is calculated for the item. This means that you can modify the behaviour of the item by plugging in a method that calculates the price the way you want If you do not provide a pricing policy, a default policy will be used. The example creates an item. It then sets the SeniorCitizenDiscountPolicy as the default pricing policy for the item. Then the item's price is calculated using the default policy. Finally, it modifies the item's quantity and once again, and calculates the price by using the AprilFoolsDiscountPolicy policy. To better understand this example, first go through the Axiom example first.
The concept is also used in our BuyBeans.com online store where different pricing policies of BuyBeans are used for calculating the prices of examples.buybeans.item.BeanieBaby, examples.buybeans.item.CoffeeBean, and examples.buybeans.item.JellyBean components. They use BeanieBabyPricePolicy, CoffeeBeanPricePolicy, and JellyBeanPricePolicy respectively.
BusinessPolicy Example
The BusinessPolicy example application performs the following steps:
To get the most out of this example, first read through BusinessPolicyExample.java on our web site. Then you can build it and run it.
Note: Be sure to set your CLASSPATH as described in How to Build and Run the Examples.
PassByValue
Sometimes it is useful to get or set all of the attributes of an object with a single method call. When dealing with remote objects that are persisted in the database, this results in a tremendous performance gain. BEA's WebLogic Commerce Server components give you that flexibility.
Package examples.passbyvalue
Shows the use of BEA WebLogic Commerce Server components' pass-by-value feature. This example demonstrates:
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Pass-by-value example. |
Package examples.passbyvalue Description
Shows the use of BEA WebLogic Commerce Server' pass-by-value feature.This example demonstrates:
Getting and Setting Attributes Using pass-by-value
This example shows how you can get and set the attributes of an Entity Component by value. What this means is that instead of getting/setting one attribute at a time, you can request that a local copy of all attributes be sent to you directly, in one remote call. You can then read and modify this "Value object" or local copy, and send it back in one remote call. This has tremendous performance advantages compared to accessing one attribute at a time It is also important to be able to set many attributes within a single transaction without having to begin/commit a JTS User Transaction from the client. In short, pass-by-value is really handy! Our implementation is tightly-coupled: that means that at compile time, we enforce type consistency for getting/setting attributes in the value objects. This has an advantage over "parameter sets"and "late-binding" implementations where you pass around a set of name/value pairs: with these approaches, if you change the type of an attribute your client will still compile but crash at runtime. This won't happen using WebLogic Commerce Server, since the value object will change accordingly and the client would not compile if an assignment was illegal. In addition, our value objects are generated by BEA SmartGenerator (based on a UML model), so they don't add any maintenance costs.
Pass By Value Example
The PassByValue example application performs the following steps:
To get the most out of this example, first read through PassByValueExample.java on our web site. Then you can build it and run it.
Note: Be sure to set your CLASSPATH as described in How to Build and Run the Examples.
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Copyright © 2000 BEA Systems, Inc. All rights reserved.
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