/// <summary>
/// Returns an instance of a resource repository accessor for a Belongs To relationship.
/// </summary>
/// <typeparam name="TEntity">The type of entity to return.</typeparam>
/// <param name="relationship">The relationship that defines the accessor to return.</param>
/// <returns>The resource repository accessor instance.</returns>
public Func <IDatabase, IRepositoryAccessor <TEntity> > GetOrCreateBelongsToAccessor <TEntity>(IBelongsToRelationship relationship)
{
return((Func <IDatabase, IRepositoryAccessor <TEntity> >)_cache.GetOrAdd(relationship, r => CreateBelongsToAccessor <TEntity>()));
}
/// <summary>
/// Create the belongs to getter expression.
/// </summary>
/// <typeparam name="TSource">The type of the source resource to enrich.</typeparam>
/// <param name="relationship">The relationship to create the accessor for.</param>
/// <param name="sourceParameter">The source parameter for the expression.</param>
/// <returns>The expression that returns the getter for the relationship.</returns>
static Expression <Func <TSource, int?> > CreateBelongsToAccessorExpression <TSource>(IBelongsToRelationship relationship, ParameterExpression sourceParameter)
{
if (relationship.BackingField.Accessor.ValueType == typeof(int?))
{
return(Expression
.Lambda <Func <TSource, int?> >(
Expression.PropertyOrField(
sourceParameter,
relationship.BackingField.Name),
sourceParameter));
}
return(Expression
.Lambda <Func <TSource, int?> >(
Expression.Convert(
Expression.PropertyOrField(
sourceParameter,
relationship.BackingField.Name),
typeof(int?)),
sourceParameter));
}
/// <summary>
/// Get or create an instance of a belongs to resource accessor.
/// </summary>
/// <typeparam name="TSource">The type of the source resource to enrich.</typeparam>
/// <typeparam name="TDestination">The type of the destination resource that is enriched on the source.</typeparam>
/// <param name="relationship">The relationship to create the accessor for.</param>
/// <returns>The belongs to resource accessor.</returns>
IBelongsToResourceAccessor <TSource, TDestination> CreateBelongsToAccessor <TSource, TDestination>(IBelongsToRelationship relationship)
{
var sourceParameter = Expression.Parameter(typeof(TSource));
var destinationParameter = Expression.Parameter(typeof(TDestination));
return(new DelegatingBelongsToResourceAccessor <TSource, TDestination>(
CreateBelongsToAccessorExpression <TSource>(relationship, sourceParameter).Compile(),
Expression
.Lambda <Action <TSource, TDestination> >(
Expression.Assign(
Expression.PropertyOrField(
sourceParameter,
relationship.Name),
destinationParameter),
sourceParameter,
destinationParameter)
.Compile()));
}
/// <summary>
/// Get or create an instance of a belongs to resource accessor.
/// </summary>
/// <typeparam name="TSource">The type of the source resource to enrich.</typeparam>
/// <typeparam name="TDestination">The type of the destination resource that is enriched on the source.</typeparam>
/// <param name="relationship">The relationship to create the accessor for.</param>
/// <returns>The belongs to resource accessor.</returns>
public IBelongsToResourceAccessor <TSource, TDestination> GetOrCreateBelongsToAccessor <TSource, TDestination>(IBelongsToRelationship relationship)
{
return((IBelongsToResourceAccessor <TSource, TDestination>)_cache.GetOrAdd(relationship, r => CreateBelongsToAccessor <TSource, TDestination>((IBelongsToRelationship)r)));
}
/// <summary>
/// Create a belongs to enricher for the given relationship.
/// </summary>
/// <param name="relationship">The relationship to create the enricher from.</param>
/// <param name="database">The database to perform the enrichment within.</param>
/// <returns>The enricher for the given resource and relationship.</returns>
IResourceEnricher <TSource, TDestination> CreateBelongsToEnricher <TSource, TDestinationEntity, TDestination>(IBelongsToRelationship relationship, IDatabase database)
where TDestinationEntity : IEntityWithId
where TDestination : IEntityWithId
{
var foreignKeyAccessor = _resourceAccessorFactory.GetOrCreateBelongsToAccessor <TSource, TDestination>(relationship);
var repositoryAccessorFactory = _repositoryAccessorFactory.GetOrCreateBelongsToAccessor <TDestinationEntity>(relationship);
return(new DelegatingBelongsToResourceEnricher <TSource, TDestinationEntity, TDestination>(
foreignKeyAccessor,
repositoryAccessorFactory(database)));
}
/// <summary>
/// Create a belongs to enricher for the given relationship.
/// </summary>
/// <typeparam name="TSource">The resource type to create the enricher for.</typeparam>
/// <typeparam name="TDestination">The resource type on the other end of the relationship that is being enriched from.</typeparam>
/// <param name="relationship">The relationship to create the enricher from.</param>
/// <param name="database">The database to perform the enrichment within.</param>
/// <returns>The enricher for the given resource and relationship.</returns>
IResourceEnricher <TSource, TDestination> CreateBelongsToEnricher <TSource, TDestination>(IBelongsToRelationship relationship, IDatabase database)
{
var parameters = new[]
{
Expression.Parameter(typeof(IBelongsToRelationship)),
Expression.Parameter(typeof(IDatabase))
};
var methodCallExpression = Expression.Call(
Expression.Constant(this),
nameof(CreateBelongsToEnricher),
new[]
{
typeof(TSource),
relationship.RelatedTo.BaseType,
relationship.RelatedTo
},
// ReSharper disable once CoVariantArrayConversion
parameters);
var @delegate = Expression
.Lambda <Func <IBelongsToRelationship, IDatabase, IResourceEnricher <TSource, TDestination> > >(
methodCallExpression,
parameters)
.Compile();
return(@delegate(relationship, database));
}
