/// <summary>
/// This method is virtual and implements
/// <see cref="IProvideParts{TTarget}.ProvideParts{T}"/>.
/// This implementation invokes all participants added here.
/// Notice that each is invoked in a catch block, and this will trace exceptions,
/// AND re-throw a new <see cref="AggregateException"/> if there are
/// any exceptions.
/// catch this exception and set the <see cref="IComposer{TTarget}.LastComposeErrors"/>.
/// </summary>
/// <param name="eventArgs"><see cref="IProvideParts{TTarget}"/> argument.</param>
/// <exception cref="AggregateException"></exception>
public virtual void ProvideParts <T>(ProvidePartsEventArgs <T> eventArgs)
where T : TTarget
{
lock (Participants) {
checkDisposed();
List <Exception> exceptions = new List <Exception>(Participants.Count);
foreach (IProvideParts <TTarget> participant
in Participants.OfType <IProvideParts <TTarget> >())
{
try {
participant.ProvideParts(eventArgs);
} catch (Exception exception) {
TraceSources.For(GetType())
.Error(
exception,
"Participant exception invoking ProvideParts: {0}, '{1}'.",
participant,
exception.Message);
exceptions.Add(exception);
}
}
if (exceptions.Count != 0)
{
throw new AggregateException(
$"One or more exceptions was raised by a {GetType().GetFriendlyName()} participant in"
+ $" {nameof(IProvideParts<TTarget>.ProvideParts)}.",
exceptions.EnumerateInReverse());
}
}
}
public void ProvideParts <T>(ProvidePartsEventArgs <T> eventArgs)
where T : MyTarget
{
eventArgs.Target.AddPart(new MyPart());
eventArgs.Target.AddPart(new MyPart());
eventArgs.Target.AddPart(new MyPart());
}
/// <summary>
/// This virtual method provides the implementation for
/// <see cref="IProvideParts{TTarget}"/>.
/// This enumerates the files on the <see cref="DirectoryWatcher"/> with the
/// <see cref="SearchOption"/>, and loads each path with <see cref="TryLoadAssembly"/>.
/// This method catches and traces all exceptions; and also provides support for
/// <see cref="ProvideAssembliesOneTimeOnly"/>.
/// </summary>
public virtual void ProvideParts <T>(ProvidePartsEventArgs <T> eventArgs)
where T : ContainerConfiguration
{
List <Assembly> assemblies = new List <Assembly>();
if (DirectoryWatcher.PathExists)
{
try {
foreach (string filePath in Directory.EnumerateFiles(
DirectoryWatcher.Path,
DirectoryWatcher.Filter,
SearchOption))
{
if (TryLoadAssembly(filePath, out Assembly assembly))
{
assemblies.Add(assembly);
}
}
} catch (Exception exception) {
TraceSources.For <MefDirectoryPartWatcher>()
.Warning(
exception,
"Catching exception enumerating files in the watched directory: '{0}'.",
exception.Message);
}
}
if (assemblies.Count == 0)
{
return;
}
lock (ComposedAssemblies) {
if (ProvideAssembliesOneTimeOnly)
{
foreach (Assembly assembly in new List <Assembly>(assemblies))
{
if (!ComposedAssemblies.Contains(assembly))
{
ComposedAssemblies.Add(assembly);
}
else
{
assemblies.Remove(assembly);
}
}
if (assemblies.Count == 0)
{
return;
}
}
}
if (Conventions != null)
{
eventArgs.Target.WithAssemblies(assemblies, Conventions);
}
else
{
eventArgs.Target.WithAssemblies(assemblies);
}
}
/// <summary>
/// This virtual method provides the implementation for
/// <see cref="IProvideParts{TTarget}"/>.
/// This adds all <see cref="ProvidedAssemblies"/>, with the optional
/// <see cref="Conventions"/> if set.
/// </summary>
public virtual void ProvideParts <T>(ProvidePartsEventArgs <T> eventArgs)
where T : ContainerConfiguration
{
if (Conventions != null)
{
eventArgs.Target.WithAssemblies(ProvidedAssemblies, Conventions);
}
else
{
eventArgs.Target.WithAssemblies(ProvidedAssemblies);
}
}
public void ProvideParts <T>(ProvidePartsEventArgs <T> eventArgs)
where T : IContainerBase
=> eventArgs.Target.RegisterType <IComponent1, Component1>();
public virtual void ProvideParts <T>(ProvidePartsEventArgs <T> eventArgs)
where T : TTarget
{
checkDisposed();
provideParts?.Invoke(new DelegateProvidePartsEventArgs <TTarget, T>(eventArgs));
}
public void ProvideParts <T>(ProvidePartsEventArgs <T> eventArgs)
where T : TTarget
=> (Participant as IProvideParts <TSuper>)?.ProvideParts(eventArgs);
/// <summary>
/// Constructor.
/// </summary>
/// <param name="eventArgs">Required.</param>
/// <exception cref="ArgumentNullException"/>
public DelegateProvidePartsEventArgs(ProvidePartsEventArgs <T> eventArgs)
: base(eventArgs.Target, out _)
=> this.eventArgs = eventArgs ?? throw new ArgumentNullException(nameof(eventArgs));
