public void RegisterConventions(IConventionsBuilder builder, IEnumerable<TypeInfo> candidateTypes)
{
builder
.ForTypesDerivedFrom(typeof(ICalculator))
.Export(
b => b.AsContractType(typeof(ICalculator))
.AddMetadata("type", t => t.Name.StartsWith("Scientific") ? "Scientific" : "Classical"))
.Shared();
}
/// <summary>
/// Tries to get the part builder.
/// </summary>
/// <param name="serviceContractMetadata">The service contract metadata.</param>
/// <param name="serviceContract">The service contract.</param>
/// <param name="conventions">The conventions.</param>
/// <param name="typeInfos">The type infos.</param>
/// <returns>
/// The part builder or <c>null</c>.
/// </returns>
private IPartConventionsBuilder TryGetPartBuilder(
AppServiceContractAttribute serviceContractMetadata,
TypeInfo serviceContract,
IConventionsBuilder conventions,
IEnumerable<TypeInfo> typeInfos)
{
var serviceContractType = serviceContract.AsType();
if (serviceContract.IsGenericTypeDefinition)
{
// if there is non-generic service contract with the same full name
// then add just the conventions for the derived types.
return conventions.ForTypesMatching(t => this.MatchOpenGenericContractType(t, serviceContractType));
}
if (serviceContractMetadata.AllowMultiple)
{
// if the service contract metadata allows multiple service registrations
// then add just the conventions for the derived types.
return conventions.ForTypesDerivedFrom(serviceContractType);
}
var parts =
typeInfos.Where(
ti =>
serviceContract.IsAssignableFrom(ti) && ti.IsClass && !ti.IsAbstract
&& ti.GetCustomAttribute<ExcludeFromCompositionAttribute>() == null).ToList();
if (parts.Count == 1)
{
return conventions.ForType(parts[0].AsType());
}
if (parts.Count > 1)
{
var overrideChain =
parts.ToDictionary(
ti => ti,
ti =>
ti.GetCustomAttribute<OverridePriorityAttribute>() ?? new OverridePriorityAttribute(Priority.Normal))
.OrderBy(item => item.Value.Value)
.ToList();
var selectedPart = overrideChain[0].Key;
if (overrideChain[0].Value.Value == overrideChain[1].Value.Value)
{
throw new InvalidOperationException(
string.Format(
Strings.AmbiguousOverrideForAppServiceContract,
serviceContract,
selectedPart,
string.Join(", ", overrideChain.Select(item => item.Key.ToString() + ":" + item.Value.Value))));
}
return conventions.ForType(selectedPart.AsType());
}
return null;
}
