Leandro. Essa sua pergunta tem mais sentido na lista enterprise, mas... Uma explica��o clara para auxiliar na escolha do tipo de Session para cada situa��o analisada
Alvaro Leia isso. "Stateful versus Stateless Session Beans EJB offers two forms of session beans: stateful and stateless. The choice between these can significantly affect system scalability. Each has strengths and weaknesses. Stateful session beans provide a convenient stash for conversational state in the application. Consequently, they make an application easier to program. But stateful beans have their dark side. Because they hold state, they must be mapped one to one with application clients. Thus, if an application has 10,000 concurrent clients it must manage 10,000 stateful session beans. How many beans can a container manage and maintain acceptable performance? Well, more than you might think, but not too many. To help with this problem, stateful beans have a complex lifecycle that includes the possibility of the passivation and activation by the container. But passivation and activation are not without cost. The bean's state information must be committed into and recovered from the database, and the bean must be reinstantiated and populated upon activation. By contrast, stateless session beans are more complex to program: if an application must save conversational state, this information must be accommodated somewhere else in the application architecture. For example, the application might commit state information into the database or stash it in some other artifact in the system (HTTP session state, etc.). The important advantage of stateless beans is that they can be shared among many clients. The basic approach is to create a pool of the stateless bean references. Clients grab a bean reference out of the pool, use it for a method invocation, and return it to the pool for another client to use. Using this scheme, 10,000 concurrent users might be served by a few hundred beans Systems using stateless or stateful beans will ultimately differ in their ability to scale. Because stateless beans can be multiplexed across many clients, systems built on stateless beans can scale to larger number of users. However, stateful beans are a very legitimate choice for small applications (those serving a few hundred concurrent users). By contrast, large-scale applications (those serving many thousands of concurrent users) clearly need to use stateless beans in order to scale. So what of the gray area we run into with applications serving a few hundred to a few thousands clients? At what point do you say that stateful beans are too costly and move on to stateless? Unfortunately, there is not wide industry experience with this technology and so the answer is unknown. Over time, metrics will arise to help guide this decision. In the meantime, perhaps the best rule of thumb is that if the number of users could possibly -- ever, in your wildest dreams -- grow beyond a few thousand, go stateless." Leandro Franchi wrote: > Ol� lista, gostaria de saber qual � a diferen�a entre EJB Sessions > Stateful e Stateless... > > Grato > > Leandro Franchi > ------------------------------ LISTA SOUJAVA ---------------------------- http://www.soujava.org.br - Sociedade de Usu�rios Java da Sucesu-SP d�vidas mais comuns: http://www.soujava.org.br/faq.htm regras da lista: http://www.soujava.org.br/regras.htm historico: http://www.mail-archive.com/java-list%40soujava.org.br para sair da lista: envie email para [EMAIL PROTECTED] -------------------------------------------------------------------------
