42 lines
1.8 KiB
C#
42 lines
1.8 KiB
C#
#if NET
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namespace DigitalData.Core.Abstractions;
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/// <summary>
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/// A deferred implementation of <see cref="IServiceProvider"/> that allows the <see cref="IServiceProvider"/> instance
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/// to be provided at a later time via a factory callback.
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/// </summary>
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/// <remarks>
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/// This is particularly useful when service registration requires an <see cref="IServiceProvider"/> instance,
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/// but the service provider is not yet available at registration time.
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/// By using <see cref="DeferredServiceProvider"/>, a service can safely resolve dependencies once
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/// the application's service provider has been built, ensuring a single consistent scope.
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/// </remarks>
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public class DeferredServiceProvider : IServiceProvider
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{
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private Lazy<IServiceProvider>? _serviceProvider;
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/// <summary>
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/// Sets the factory that will be used to lazily initialize the <see cref="IServiceProvider"/> instance.
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/// </summary>
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public Func<IServiceProvider> Factory
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{
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set => _serviceProvider = new(value);
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}
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/// <summary>
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/// Retrieves the requested service object from the deferred <see cref="IServiceProvider"/>.
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/// </summary>
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/// <param name="serviceType">The type of service object to retrieve.</param>
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/// <returns>The requested service object, or <c>null</c> if the service is not available.</returns>
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/// <exception cref="InvalidOperationException">
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/// Thrown if the service provider factory has not been set before calling <see cref="GetService"/>.
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/// </exception>
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public object? GetService(Type serviceType)
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{
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if (_serviceProvider is null)
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throw new InvalidOperationException("The service provider has not been initialized. Make sure 'Factory' is set before calling 'GetService'.");
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return _serviceProvider.Value.GetService(serviceType);
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}
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}
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#endif |