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    <p>It seems like the main service could maintain a dictionary of plugins, indexed by name. Then for a client to see if the server provides a particular service, all the main service has to do is look up the name in the dictionary. And to process, the service just has to call a method on the object that's in the value portion of the dictionary entry. An example:</p> <p>You have three abstract classes: <code>Service</code>, <code>ServiceResult</code>, and <code>ServiceTask</code>. The contents of <code>ServiceTask</code> and <code>ServiceResult</code> aren't really important for this discussion. <code>Service</code> must have a parameterless constructor and a method called <code>Process</code> that takes a <code>ServiceTask</code> as its sole parameter. So your differential equation solver would look like:</p> <pre><code>public class DiffeqSolver : Service { public DiffeqSolver() { // do any required initialization here } public ServiceResult Process(ServiceTask task) { DiffeqTask dtask = task as DiffeqTask; if (dtask == null) { // Error. User didn't pass a DiffeqTask. // Somehow communicate error back to client. } // Here, solve the diff eq and return the result. } } </code></pre> <p>The main service is somehow notified of existing plugins. It maintains a dictionary:</p> <pre><code>Dictionary&lt;string, Service&gt; Services = new Dictionary&lt;string, Service&gt;(); </code></pre> <p>I assume you have some idea how you're going to load the plugins. What you want, in effect, is for the dictionary to contain:</p> <pre><code>Key = "DiffeqSolver", Value = new DiffeqSolver(); Key = "ServiceType1", Value = new ServiceType1(); etc., etc. </code></pre> <p>You can then have two methods for the main service: <code>ServiceIsSupported</code> and <code>Process</code>:</p> <pre><code>bool ServiceIsSupported(string serviceName) { return Services.ContainsKey(serviceName); } ServiceResult Process(string serviceName, ServiceTask task) { Service srv; if (Services.TryGetValue(serviceName, out srv)) { return srv.Process(task); } else { // The service isn't supported. // Return a failure result return FailedServiceResult; } } </code></pre> <p>I've simplified that to some extent. In particular, I'm using a <code>Dictionary</code>, which is not thread safe. You'd want to use a <code>ConcurrentDictionary</code>, or use locks to synchronize access to your dictionary.</p> <p>The more difficult part, I think, will be loading the plugins. But there are many available examples of creating a plugin architecture. I think you can find what you need.</p>
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    1. POHow to separate the layer of the communication and processing?
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    1. USJim Mischel
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    1. POHow to separate the layer of the communication and processing?
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    1. COYes, your example more or less reflects the solution that I thought! The only difference is that I thought of using two WCF services (one to check if a certain plugin is supported, and the other for processing), but I think I will take inspiration from your example by implementing a single WCF service with the methods `ServiceIsSupported` and `Process`. Thank you very much for your reply!
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    2. COWhat are the limitations of using a single service (ie a single method `Process` for different types of processing)? Are there any disadvantages to using this approach that could be eliminated by using a multi-service approach (a service for each type of processing)?
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    3. CO@enzom83: If you have a separate service for each type of processing, then any time you add a new plugin, you'll have to add a new service. That makes adding a plugin somewhat more complicated. I don't see that there's any disadvantage to using a single `Process` method, and it's a lot easier to implement.
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