Private Components and Assemblies
Private components and assemblies are the other new and very important features that are brought by Windows XP and COM+1.5. Private component is a component that is to be accessed only by other components in the same application, same as that a private assembly is an assembly which only visible to one application. Private components are required in approximately all enterprise class COM+ projects.
Similar to that most of the .NET applications need minimum one private assembly to isolate the application from changes made to the system by other applications. Also, if you do not want to give permission to a client for accessing to a component and assembly, you need to deploy them as private. Please note, a private assembly can include more than one private component. In COM1.5 each component has a select box under the activation tab to mark it private or not private. Furthermore, you can mark a component programmatically private.
Disabling Components
Components can be disabled on a case-by-case basis from the component’s popup context menu by using Disabled option. After disabling a component, you may see a red square on component’s icon. If you see this red square on any component’s icon, which means before using this component you must enable it. Because, all software from client computer, which attempt to create a disabled component, will be failed and they will have a message that the component has been disabled.
If you need to disable any type component including the legacy components in a COM+1.5 applications, you can use this disabling method. When you disable a component this will only influence activation requests and, the other existing object’s references will not be affected. Finally, when you need to enable a component just use the context menu and enable it.
Disabling Application
You can disable applications just as you can disable components. When you disable an application, all client attempts to create components from that application will fail, with the following message returned: “The component has been disabled." To disable an application, display its popup context menu and select Disable. When an application is disabled, a red square also is displayed on its icon in the COM+ 1.5 Explorer. If you need to enable a disabled application, bring up the context menu again and select Enable.
Disabling an application has two beneficial points. The first one is that if you need to upgrade or change fundamental structure of the software in a live server computer there are two choices for you: shut down the application or disable the application. Of course disabling the application will be better than shutting down the application. Because, this will allow the existing client to finish its job, also, it will hold the existing references to this application. And the second beneficial point is that in the testing and developing phase you need to verify the failure of the client’s attempt to this application and disabling an application will provide you this opportunity.
You should keep in mind that before deploying your application you must test all those kind of failure attempts to your application. Because, after releasing your enterprise class application this kind of failure will cause major technical problems. After all, disabling application is a very important tool for you. It is important that, you can not disable Legacy applications but you can disable a COM+ 1.5 application. It is interesting that a client computer that already has a reference to a COM+ object is not influenced by the fact that the application has been disabled. Only client computers that try to create new objects are affected. Accordingly, you can have a disabled application running for an indefinite period on a client computer or more than one.
Pausing Application
Pausing to an application and disabling an application are similar, except pausing is used to disable a particular running process only, and an application shutdown terminates the paused status. If you need to pause a process, open the Running Processes folder and select Pause from the application's context menu and to resume it, choose Resume.
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