A naming reference is a string used by the application to look up an object in the given naming context. For each Web application, there is a naming context and the references are configured in the standard component deployment descriptors.This section describes the standard deployment descriptor features used in Sun Java System Web Server. This section covers the following topics:
Environment entries, defined using <env-entry>, provide a way of specifying deployment time parameters to J2SE Web applications. Note that the servlet context initialization parameters could be defined using <context-param>, but <env-entry> is the preferred way because application deployers to configure such applications parameters by explicitly specifying the name, type and values for them.
The following sample describes the syntax of <env-entry> as specified in the J2SE standard deployment descriptors:
<env-entry> <description> Send pincode by mail </description> <env-entry-name> mailPincode </env-entry-name> <env-entry-value> false </env-entry-value> <env-entry-type> java.lang.Boolean </env-entry-type> </env-entry>
The <env-entry-type> tag specifies a fully qualified class name for the entry. Here is a code snippet to lookup the <env-entry> using JNDI from a servlet or JSP:
Context initContext = new InitialContext(); Boolean mailPincode = (Boolean) initContext.lookup("java:comp/env/mailPincode"); // one could use relative names into the sub-context Context envContext = initContext.lookup("java:comp/env"); Boolean mailPincode = (Boolean) envContext.lookup("mailPincode");
A factory is an object that creates other objects on demand. A resource factory creates resource objects, such as database connections or message service connections. They are configured using <resource-ref> element in the standard deployment descriptors.
The following example describes the use of factories: