/// <summary>
/// Selects the best constructor from the available constructors.
/// </summary>
/// <param name="constructorBindings">Available constructors.</param>
/// <returns>The best constructor.</returns>
/// <exception cref='DependencyResolutionException'>A single unambiguous match could not be chosen.</exception>
public ConstructorParameterBinding SelectConstructorBinding(ConstructorParameterBinding[] constructorBindings)
{
if (constructorBindings == null) throw new ArgumentNullException("constructorBindings");
if (constructorBindings.Length == 0) throw new ArgumentOutOfRangeException("constructorBindings");
if (constructorBindings.Length == 1)
return constructorBindings[0];
var withLength = constructorBindings
.Select(binding => new { Binding = binding, ConstructorParameterLength = binding.TargetConstructor.GetParameters().Length });
var maxLength = withLength.Max(binding => binding.ConstructorParameterLength);
var maximal = withLength
.Where(binding => binding.ConstructorParameterLength == maxLength)
.Select(ctor => ctor.Binding)
.ToArray();
if (maximal.Length == 1)
return maximal[0];
throw new DependencyResolutionException(string.Format(
CultureInfo.CurrentCulture,
MostParametersConstructorSelectorResources.UnableToChooseFromMultipleConstructors,
maxLength,
maximal[0].TargetConstructor.DeclaringType));
}
/// <summary>
/// Selects the best constructor from the available constructors.
/// </summary>
/// <param name="constructorBindings">Available constructors.</param>
/// <returns>The best constructor.</returns>
/// <exception cref='DependencyResolutionException'>A single unambiguous match could not be chosen.</exception>
public ConstructorParameterBinding SelectConstructorBinding(ConstructorParameterBinding[] constructorBindings)
{
if (constructorBindings == null) throw new ArgumentNullException("constructorBindings");
if (constructorBindings.Length == 0) throw new ArgumentOutOfRangeException("constructorBindings");
if (constructorBindings.Length == 1)
return constructorBindings[0];
var withLength = constructorBindings
.Select(binding => new { Binding = binding, ConstructorParameterLength = binding.TargetConstructor.GetParameters().Length });
var maxLength = withLength.Max(binding => binding.ConstructorParameterLength);
var maximal = withLength
.Where(binding => binding.ConstructorParameterLength == maxLength)
.Select(ctor => ctor.Binding)
.ToArray();
if (maximal.Length == 1)
return maximal[0];
throw new DependencyResolutionException(string.Format(
"Cannot choose between multiple constructors with equal length {0} on type '{1}'. Select the constructor explicitly, with the UsingConstructor() configuration method, when the component is registered.",
maxLength,
maximal[0].TargetConstructor.DeclaringType));
}
public void WhenAnExceptionIsThrownFromAConstructor_TheInnerExceptionIsWrapped()
{
var ci = typeof(ThrowsInCtor).GetTypeInfo().DeclaredConstructors.Single();
var cpb = new ConstructorParameterBinding(
ci, Enumerable.Empty<Parameter>(), new ContainerBuilder().Build());
var dx = Assert.Throws<DependencyResolutionException>(() =>
cpb.Instantiate());
Assert.True(dx.Message.Contains(typeof(ThrowsInCtor).Name));
Assert.Equal(ThrowsInCtor.Message, dx.InnerException.Message);
}
/// <summary>
/// Selects the best constructor from the available constructors.
/// </summary>
/// <param name="constructorBindings">Available constructors.</param>
/// <returns>The best constructor.</returns>
public ConstructorParameterBinding SelectConstructorBinding(ConstructorParameterBinding[] constructorBindings)
{
if (constructorBindings == null) throw new ArgumentNullException("constructorBindings");
var result = constructorBindings
.Where(b => b.TargetConstructor.GetParameters().Select(p => p.ParameterType).SequenceEqual(_signature))
.ToArray();
if (result.Length == 1)
return result[0];
if (!constructorBindings.Any())
throw new ArgumentException(MatchingSignatureConstructorSelectorResources.AtLeastOneBindingRequired);
var targetTypeName = constructorBindings.First().TargetConstructor.DeclaringType.Name;
var signature = string.Join(", ", _signature.Select(t => t.Name).ToArray());
if (result.Length == 0)
throw new DependencyResolutionException(string.Format(CultureInfo.CurrentCulture, MatchingSignatureConstructorSelectorResources.RequiredConstructorNotAvailable, targetTypeName, signature));
throw new DependencyResolutionException(string.Format(CultureInfo.CurrentCulture, MatchingSignatureConstructorSelectorResources.TooManyConstructorsMatch, signature));
}
private ConstructorParameterBinding[] GetValidConstructorBindings(IComponentContext context, IEnumerable <Parameter> parameters)
{
// Most often, there will be no `parameters` and/or no `_defaultParameters`; in both of those cases we can avoid allocating.
var prioritisedParameters = parameters.Any() ?
(_defaultParameters.Length == 0 ? parameters : parameters.Concat(_defaultParameters)) :
_defaultParameters;
var constructorBindings = new ConstructorParameterBinding[_availableConstructors.Length];
for (var i = 0; i < _availableConstructors.Length; ++i)
{
constructorBindings[i] = new ConstructorParameterBinding(_availableConstructors[i], prioritisedParameters, context);
}
// Copy-on-write; 99% of components will have a single constructor that can be instantiated.
var validBindings = constructorBindings;
for (var i = 0; i < constructorBindings.Length; ++i)
{
if (!constructorBindings[i].CanInstantiate)
{
// Further optimisation opportunity here
validBindings = constructorBindings
.Where(cb => cb.CanInstantiate)
.ToArray();
break;
}
}
if (validBindings.Length == 0)
{
throw new DependencyResolutionException(GetBindingFailureMessage(constructorBindings));
}
return(validBindings);
}
public ConstructorParameterBinding SelectConstructorBinding(ConstructorParameterBinding[] constructorBindings)
{
return null;
}
/// <summary>
/// Selects the best constructor from the available constructors.
/// </summary>
/// <param name="constructorBindings">Available constructors.</param>
/// <returns>
/// The best constructor.
/// </returns>
public ConstructorParameterBinding SelectConstructorBinding(ConstructorParameterBinding[] constructorBindings)
{
return constructorBindings.First();
}