 | Mailing List | | Home | | Forum Home | | JBoss - Java Application Server | | Struts - A MVC web framework | | Tomcat - JSP/Servlet container | | iText - An open source PDF Java Library | | JDOM - JDOM XML Parser | | J2EE - A mailing list for Java(tm) 2 Platform, Enterprise Edition | | J2EE Pattern - An interest list for Sun Java Center J2EE Pattern Catalog | | Servlet - A mailing list for discussion about Sun Microsystem's Java Servlet API Technology | | JSP - A mailing list about Java Server Pages specification and reference | |
Struts & Hibernate
|
|
|
| | | Why two different serviceLocators in petstore demo 1.3 ?? | Why two different serviceLocators in petstore demo 1.3 ?? 2003-10-08 - By Ricardo de Souza Moura
Back
Imagine the situation:
I have a client application that access a remote EJBServer and in my client
app I cache the JNDI context and EJBHome. If I need restart my EJBServer
what happen with my cache objects ?
>From: Sean Brydon <Sean.Brydon@(protected)>
>Reply-To: An interest list for Sun Java Center J2EE Pattern Catalog
><J2EEPATTERNS-INTEREST@(protected)>
>To: J2EEPATTERNS-INTEREST@(protected)
>Subject: Re: Why two different serviceLocators in petstore demo 1.3 ??
>Date: Mon, 6 Oct 2003 11:21:21 -0700
>
>Hi,
>
>We have 2 examples of service locator pattern, one with caching and the
>other with no caching. The web tier uses the caching version, where as
>in the opc application of petstore which is all EJBs and has no view or
>web tier, it uses no caching for the service locator. It is not clear
>that there is any performance benefit from this caching mechanism in
>EJBs since the container closely manages objects and their
>lifecycle.Since performane is the primary reason for this caching
>strategy with the service locator, you might want to do some testing
>before you choose a strategy to optimize for performance in your
>deployment environment.
>Also, this way you get examples of 2 different strategies :-)
>This is explained in more detail at
>http://java.sun.com/blueprints/patterns/ServiceLocator.html
>
>hope that helps,
>Sean
>
>
>peng wang wrote:
>
>>Hi,
>>
>>In petstore, I find there are two kinds of service
>>locators, one is for the web tier, the other for the
>>ejb tier.
>>
>>In web tier a componentManager gets locator instance
>>by invoking static method:
>> static public ServiceLocator getInstance() {
>> return me;
>> }
>>Since there is only one instance, does it then form a
>>bottle neck in web tier?
>>
>>In ejb tier, an ejbAction get locator by creating a
>>new
>>instance like:
>> ServiceLocator sl = new ServiceLocator();
>>So I think there are multi serviceLocator instances in
>>
>>the ejb tier(differing from web tier).
>>
>>What is the force for two kinds of serviceLocators in
>>petstore application? When need to use the first, and
>>when the second??
>>
>>Thanks!
>>
>>__ ____ ____ ____ ____ ____ ______
>>Do you Yahoo!?
>>The New Yahoo! Shopping - with improved product search
>>http://shopping.yahoo.com
>>
>>====================================================================
>>Companion Site: http://www.corej2eepatterns.com
>>J2EE BluePrints: http://java.sun.com/blueprints/corej2eepatterns
>>List Archive:
>>http://archives.java.sun.com/archives/j2eepatterns-interest.html
>>Unsubscribing: email "signoff J2EEPATTERNS-INTEREST" to
>>listserv@(protected)
>>
>>
>
>====================================================================
>Companion Site: http://www.corej2eepatterns.com
>J2EE BluePrints: http://java.sun.com/blueprints/corej2eepatterns
>List Archive:
>http://archives.java.sun.com/archives/j2eepatterns-interest.html
>Unsubscribing: email "signoff J2EEPATTERNS-INTEREST" to
>listserv@(protected)
__ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ __
MSN Messenger: converse com os seus amigos online.
http://messenger.msn.com.br
====================================================================
Companion Site: http://www.corej2eepatterns.com
J2EE BluePrints: http://java.sun.com/blueprints/corej2eepatterns
List Archive: http://archives.java.sun.com/archives/j2eepatterns-interest.html
Unsubscribing: email "signoff J2EEPATTERNS-INTEREST" to listserv@(protected)
|
|
|
