Chapter 1: Introducing EAServer
When multiple servers are involved in your application, the naming service allows you to specify logical server names rather than server addresses. For example, instead of connecting to your finance component server at host badger using port 9000, you can specify the initial naming context for that server, such as USA/MyCompany/FinanceServer. Components are identified by specifying an initial server name context plus the package and component name. For example:
This layer of abstraction allows you to move a server to another host without affecting deployed client applications. Naming does require that one EAServer installation use a well-known, stable host and port. This server acts as the name server for other servers that participate in your application, and clients connect to that server to resolve name requests.
You can use either persistent or transient storage for the naming database. For transient storage, EAServer builds the name database in memory when it starts, based on the contents of the EAServer configuration repository. For persistent storage, you must provide a third-party directory server that accepts connections using the Lightweight Directory Access Protocol (LDAP). When using persistent storage, EAServer connects to the third-party directory server to create and edit name database entries, and to resolve client name requests.
The naming configuration for a multiserver application is briefly summarized as follows:
Choose one server to act as name server for the application. You can configure this server to store names in memory (transient storage), or to store names in a third-party directory server (persistent storage).
Configure each of the remaining servers to connect to the designated EAServer naming server to resolve names. Each server also updates the name space when packages and components are added or deleted in EAServer Manager.
For detailed instructions, see Chapter 5, “Naming Services,” in the EAServer System Administration Guide.
For Java and C++ clients, EAServer provides industry-standard client-side APIs for naming services.
For Java clients, EAServer provides implementations of the CORBA standard CosNaming API and the Java Naming and Directory (JNDI) API. See Chapter 8, “Creating Enterprise JavaBeans Clients,” and Chapter 12, “Creating CORBA Java Clients,” in the EAServer Programmer’s Guide.
For C++ clients, EAServer provides an implementation of the CORBA standard CosNaming API. See Chapter 15, “Creating CORBA C++ Clients,” in the EAServer Programmer’s Guide.
PowerBuilder clients use the naming service implicitly. The name resolution is performed automatically when you create EAServer component instances using the CreateInstance and Lookup functions of the Connection object. You can browse the naming service using the CosNaming API, but such complexity is not necessary. See the Application Techniques manual in the PowerBuilder documentation.
ActiveX clients use the naming service implicitly.
|Copyright © 2005. Sybase Inc. All rights reserved.|