Chapter 4: Middle Tier

This chapter describes the deployment environment for the middle-tier components produced by SOA Express.

In this chapter, we assume that the middle tier is physically realized by one or more server-class computers.

Because many different deployment environments are possible, this chapter is more descriptive than instructive. For detailed installation instructions you must refer to the relevant product documentation.

Overview

SOA Express produces middle-tier components that conform to the JavaBeans, Enterprise JavaBeans or .NET specification.

For Java components (JavaBeans and EJBs), the middle-tier deployment environment comprises:

• Some form of application server
• WebSphere MQ to provide the link to the mainframe tier
• The IBM WebSphere MQ classes for Java.

or alternatively (CICS only):

• Some form of application server
• IBM's CICS Transaction Gateway (commonly known as ECI) to provide the link to the mainframe tier
• The ECI classes for Java.

IBM's CICS Transaction Gateway can be installed on any computer, not necessarily the middle tier.

For .NET components, the middle-tier deployment environment comprises:

• Microsoft Internet Information Server (IIS), if you plan to access .NET components using ASP.NET
• WebSphere MQ to provide the link to the mainframe tier.

SOA Express does not support the use of CICS Transaction Gateway with .NET components.

The middle-tier deployment environments for JavaBeans/EJBs and .NET components are detailed in later sections. Information on WebSphere MQ that is common to both is detailed in the following section.

IBM WebSphere MQ

WebSphere MQ is one of the supported middleware options between the middle and mainframe tiers, and the only supported middleware option if you are generating .NET components or using IMS. WebSphere MQ Server and WebSphere MQ Client products are available for various middle-tier platforms, enabling you to choose between a server-server or a client-server configuration. The term server-server configuration refers to the situation in which WebSphere MQ servers are installed both at the middle-tier computer and at the mainframe. The term client-server configuration means that a WebSphere MQ client is installed on the middle tier and a WebSphere MQ server at the mainframe.

Server-server or Client-server

The advantages of installing a WebSphere MQ server on the middle tier are:

• You don't need the Client Attachment Feature (CAF)

  If you install a WebSphere MQ client, you must also install the optional Client Attachment Feature (CAF) at the mainframe (this must be ordered separately - it is not part of WebSphere MQ Server for the mainframe). If a client attempts to contact a server without the CAF, the MQI server-connection channel will open and close immediately without reporting any error.

The advantages of installing a WebSphere MQ client on the middle tier are:

• Hardware requirements on the middle tier are reduced
• System administration is easier, because it is concentrated at the mainframe
• Initial installation costs may be lower, because at the time of writing WebSphere MQ clients can be downloaded from the IBM Web site. On the other hand, the monthly cost of the CAF may outweigh the cost of WebSphere MQ Server in certain situations.

There are two alternative WebSphere clients: the Windows Client, and Java Messaging (formerly known as WebSphere MQ Java Client). If you install WebSphere MQ Client:

• For .NET components, choose the Windows Client option.
• For Java components, choose the Java Messaging option.

Installing IBM WebSphere MQ

Follow the instructions in your platform-specific IBM WebSphere MQ: Quick Beginnings book, or your IBM WebSphere MQ Clients book, to install WebSphere MQ servers and clients respectively. You must be logged on as an administrator.

After installing WebSphere MQ, define WebSphere MQ objects as described in the chapter WebSphere MQ Middleware.

JavaBean and EJB Deployment Environment

In addition to WebSphere MQ or CICS Transaction Gateway middleware, a JavaBean/EJB deployment environment requires an application server and the Java classes for the middleware option you are using.

Application Server

An application server is needed to host the code that provides the interface between the JavaBean or EJB and its clients. For EJBs, an application server is also required to host the EJBs themselves. Many vendors offer application servers that natively or extensibly support both uses.

The JavaBeans and EJBs produced by SOA Express have been tested against the following application servers:

• IBM's WebSphere
• Oracle
• Tomcat

Further information on deploying to Web and application servers can be found in your Deployment Guide.

Installing an Application Server

Installing an application server enables you to deploy either JavaBeans or Enterprise JavaBeans components. Installation of an application server also requires:

• A supported Java Development Kit

• A supported Web server

• A supported relational database (for some application servers)

IBM WebSphere MQ Classes for Java

The WebSphere MQ Java classes to interface with JavaBeans and EJBs are installed when you install the Java Messaging option.

ECI Classes for Java

The ECI Java classes you need to interface with JavaBeans and EJBs are provided with the IBM CICS Transaction Gateway, and are located in the CTG\classes folder by default.

.NET Deployment Environment

In addition to WebSphere MQ, a .NET deployment environment requires a Microsoft Internet Information Server (IIS) Web server. SOA Express does not support the use of CICS Transaction Gateway with .NET components.

Microsoft Internet Information Server (IIS)

If you plan to deploy .NET components using ASPX test clients or as Web services, you need a .NET-enabled version of Microsoft's Internet Information Server (IIS) Web server.

Before running any ASPX clients, ensure that the user id IUSR_machinename has MQM authority in order to access WebSphere MQ. IIS uses IUSR_machinename for anonymous Internet access, where machinename is the name of the deployment machine.

IBM WebSphere MQ

In addition to the general information on IBM WebSphere MQ given at the beginning of this chapter, the following information is specific to .NET deployment environments:

• You need WebSphere MQ, with amqmdnet.dll installed in the Global Assembly Cache.
• If the owning queue manager resides on another machine (you are running WebSphere MQ Client on the IIS machine and the queue manager is on another Windows machine), make sure that the IIS guest userid is defined on the owning queue manager machine. This userid must be given MQM authority on the owning queue manager machine. Failure to do so will result in WebSphere MQ error 2035 (not authorized) at runtime.
• Set the MQSERVER environment variable when deploying on WebSphere MQ Client machines. The format of the MQServer environment variable is:

  SET MQSERVER=serverconnectionchannel\protocol\connection(port)

  Refer to the IBM WebSphere MQ Clients manual for additional information on the MQSERVER environment variable

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