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namespace System.Web.Mvc {
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Web.Mvc.Resources;
public class DependencyResolver {
// Static accessors
private static DependencyResolver _instance = new DependencyResolver();
public static IDependencyResolver Current {
get {
return _instance.InnerCurrent;
}
}
public static void SetResolver(IDependencyResolver resolver) {
_instance.InnerSetResolver(resolver);
}
public static void SetResolver(object commonServiceLocator) {
_instance.InnerSetResolver(commonServiceLocator);
}
[SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types.")]
public static void SetResolver(Func<Type, object> getService, Func<Type, IEnumerable<object>> getServices) {
_instance.InnerSetResolver(getService, getServices);
}
// Instance implementation (for testing purposes)
private IDependencyResolver _current = new DefaultDependencyResolver();
public IDependencyResolver InnerCurrent {
get {
return _current;
}
}
public void InnerSetResolver(IDependencyResolver resolver) {
if (resolver == null) {
throw new ArgumentNullException("resolver");
}
_current = resolver;
}
public void InnerSetResolver(object commonServiceLocator) {
if (commonServiceLocator == null) {
throw new ArgumentNullException("commonServiceLocator");
}
Type locatorType = commonServiceLocator.GetType();
MethodInfo getInstance = locatorType.GetMethod("GetInstance", new[] { typeof(Type) });
MethodInfo getInstances = locatorType.GetMethod("GetAllInstances", new[] { typeof(Type) });
if (getInstance == null ||
getInstance.ReturnType != typeof(object) ||
getInstances == null ||
getInstances.ReturnType != typeof(IEnumerable<object>)) {
throw new ArgumentException(
String.Format(
CultureInfo.CurrentCulture,
MvcResources.DependencyResolver_DoesNotImplementICommonServiceLocator,
locatorType.FullName
),
"commonServiceLocator"
);
}
var getService = (Func<Type, object>)Delegate.CreateDelegate(typeof(Func<Type, object>), commonServiceLocator, getInstance);
var getServices = (Func<Type, IEnumerable<object>>)Delegate.CreateDelegate(typeof(Func<Type, IEnumerable<object>>), commonServiceLocator, getInstances);
_current = new DelegateBasedDependencyResolver(getService, getServices);
}
[SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types.")]
public void InnerSetResolver(Func<Type, object> getService, Func<Type, IEnumerable<object>> getServices) {
if (getService == null) {
throw new ArgumentNullException("getService");
}
if (getServices == null) {
throw new ArgumentNullException("getServices");
}
_current = new DelegateBasedDependencyResolver(getService, getServices);
}
// Helper classes
private class DelegateBasedDependencyResolver : IDependencyResolver {
Func<Type, object> _getService;
Func<Type, IEnumerable<object>> _getServices;
public DelegateBasedDependencyResolver(Func<Type, object> getService, Func<Type, IEnumerable<object>> getServices) {
_getService = getService;
_getServices = getServices;
}
[SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes", Justification = "This method might throw exceptions whose type we cannot strongly link against; namely, ActivationException from common service locator")]
public object GetService(Type type) {
try {
return _getService.Invoke(type);
}
catch {
return null;
}
}
public IEnumerable<object> GetServices(Type type) {
return _getServices(type);
}
}
private class DefaultDependencyResolver : IDependencyResolver {
[SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes", Justification = "This method might throw exceptions whose type we cannot strongly link against; namely, ActivationException from common service locator")]
public object GetService(Type serviceType) {
try {
return Activator.CreateInstance(serviceType);
}
catch {
return null;
}
}
public IEnumerable<object> GetServices(Type serviceType) {
return Enumerable.Empty<object>();
}
}
}
}
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