Files
openstack-sdk-dotnet/Openstack/Openstack.Common/ServiceLocation/ServiceLocationManager.cs
Wayne Foley 23fdb90c2b Adding the initial code base for this repo
Change-Id: Ie3c70c76e0a96978383d2524e8af9a0cc04bd6a2
2014-03-21 12:54:41 -07:00

123 lines
4.9 KiB
C#

// /* ============================================================================
// Copyright 2014 Hewlett Packard
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ============================================================================ */
namespace Openstack.Common.ServiceLocation
{
using System;
using System.Globalization;
/// <inheritdoc/>
internal abstract class ServiceLocationManager : IServiceLocationManager
{
/// <inheritdoc/>
public void RegisterServiceInstance<TService>(TService instance)
{
this.RegisterServiceInstance(typeof(TService),
instance);
}
/// <inheritdoc/>
public abstract void RegisterServiceInstance(Type type, object instance);
/// <inheritdoc/>
public void RegisterServiceType<T>(Type registrationValue)
{
this.RegisterServiceType(typeof(T),
registrationValue);
}
/// <inheritdoc/>
public void RegisterServiceType<TInterface, TConcreate>() where TConcreate : class, TInterface
{
this.RegisterServiceType(typeof(TInterface), typeof(TConcreate));
}
/// <inheritdoc/>
public void RegisterServiceType(Type type, Type registrationValue)
{
ThrowIfInvalidRegistration(type, registrationValue);
var obj = Activator.CreateInstance(registrationValue);
this.RegisterServiceInstance(type, obj);
}
/// <summary>
/// Throws an exception if the type or implementation are null.
/// </summary>
/// <param name="type">A Type object.</param>
/// <param name="implementation">The implementation of the given Type.</param>
internal static void ThrowIfNullInstance(Type type, object implementation)
{
if (ReferenceEquals(type, null))
{
var msg = string.Format(CultureInfo.InvariantCulture,
"Cannot register a null service.");
throw new InvalidOperationException(msg);
}
if (ReferenceEquals(implementation, null))
{
var msg = string.Format(
CultureInfo.InvariantCulture,
"A service cannot have a null implementation '{0}'",
type.FullName);
throw new InvalidOperationException(msg);
}
}
/// <summary>
/// Throws an exception if the given Type and implementation represent an invalid registration.
/// An invalid registration is one where the given Type is of a restricted type, is not an interface, or the given implementation does not inherit from the given Type.
/// </summary>
/// <param name="type">A Type object.</param>
/// <param name="implementation">The implementation of the given Type.</param>
internal static void ThrowIfInvalidRegistration(Type type, Type implementation)
{
ThrowIfNullInstance(type,
implementation);
if (type == typeof(IServiceLocationRuntimeManager) ||
type == typeof(IServiceLocationOverrideManager) ||
type == typeof(IServiceLocationManager) ||
type == typeof(IServiceLocator))
{
var msg = string.Format(
CultureInfo.InvariantCulture,
"Service location services cannot be registered or overriden: '{0}'",
type.FullName);
throw new InvalidOperationException(msg);
}
if (!type.IsInterface)
{
var msg = string.Format(
CultureInfo.InvariantCulture,
"The following type: '{0}' is not an interface",
type.FullName);
throw new InvalidOperationException(msg);
}
if (!type.IsAssignableFrom(implementation))
{
var msg = string.Format(
CultureInfo.InvariantCulture,
"Cannot register or ovverride the service '{0}' for the type '{1}' which is not derived from the service",
implementation.FullName,
type.FullName);
throw new InvalidOperationException(msg);
}
}
}
}