1

我们有 3 个类负责处理图像。老板让我合并它。我将它合并到一个文件中，但他说这是同一件事，我们需要将其合并到一般逻辑中。我们如何将这 3 个吸气剂合并成一个通用吸气剂？它们仅在传递给 Type.GetType() 的参数类型上有所不同。我们需要使用一个通用属性和一个通用 getter。

public class BonusImageHandler
{
    private static IStorageProvider _BAstorageProvider; 
    private static IStorageProvider _BAWP8storageProvider;
    private static IStorageProvider _M4MstorageProvider;

    private static readonly object _lock = new object();

    private static IStorageProvider BAStorageProvider
    {
        get
        {
            lock (_lock)
            {
                if (_BAstorageProvider == null)
                {
                    lock (_lock)
                    {
                        var storageProviderType = Type.GetType(BLL.Providers.ConfigurationProvider.Instance.BAStorageProviderTypeName);
                        _BAstorageProvider = (IStorageProvider)Activator.CreateInstance(storageProviderType);
                    }
                }
            }
            return _BAstorageProvider;
        }
    }

    private static IStorageProvider BAWP8StorageProvider
    {
        get
        {
            lock (_lock)
            {
                if (_BAWP8storageProvider == null)
                {
                    lock (_lock)
                    {
                        var storageProviderType = Type.GetType(BLL.Providers.ConfigurationProvider.Instance.BAWP8StorageProviderTypeName);
                        _BAWP8storageProvider = (IStorageProvider)Activator.CreateInstance(storageProviderType);
                    }
                }
            }
            return _BAWP8storageProvider;
        }
    }

    private static IStorageProvider M4MStorageProvider
    {
        get
        {
            lock (_lock)
            {
                if (_M4MstorageProvider== null)
                {
                    lock (_lock)
                    {
                        var storageProviderType = Type.GetType(BLL.Providers.ConfigurationProvider.Instance.M4MStorageProviderTypeName);
                        _M4MstorageProvider= (IStorageProvider)Activator.CreateInstance(storageProviderType);
                    }
                }
            }
            return _M4MstorageProvider;
        }
    }

}
4

3 回答 3

2

像这样的方法：

public void GetProvider(string typeName, ref IStorageProvider provider)
{
    if (provider == null)
    {
        lock (_lock)
        {
            if (provider == null)
            {
                var storageProviderType = Type.GetType(typeName);
                provider = (IStorageProvider)Activator.CreateInstance(storageProviderType);
            }
        }
    }
}

应该做的伎俩。然后你这样称呼它：

private static IStorageProvider BAWP8StorageProvider
{
    get
    {
        GetProvider(BLL.Providers.ConfigurationProvider.Instance.BAWP8StorageProviderTypeName, ref _BAWP8storageProvider);
        return _BAWP8StorageProvider;
    }
}

虽然我个人会失去 _BAWP8StorageProvider 类成员，而只使用属性（这也会删除丑陋的ref参数）。

于 2012-08-02T11:56:29.107 回答
2

辅助方法：

static IStorageProvider GetStorageProvider(ref IStorageProvider field, string name)
{
    lock(_lock)
    {
        if(field == null)
        {
            var storageProviderType = Type.GetType(name);
            field = (IStorageProvider)Activator.CreateInstance(storageProviderType);
        }
    }
    return field;
}

用法：

private static IStorageProvider BAStorageProvider
{
    get
    {
        return GetStorageProvider(
            ref _BAstorageProvider,
            BLL.Providers.ConfigurationProvider.Instance.BAStorageProviderTypeName);
    }
}
于 2012-08-02T12:03:39.780 回答
2 
private static IStorageProvider GetProvider(string typeName)
{
    return (IStorageProvider)Activator.CreateInstance(Type.GetType(typeName));
}

private static readonly Lazy<IStorageProvider> _BAstorageProvider =
    new Lazy<IStorageProvider>(
        () => GetProvider(
            BLL.Providers.ConfigurationProvider.Instance.BAStorageProviderTypeName),
        LazyThreadSafetyMode.ExecutionAndPublication);
private static readonly Lazy<IStorageProvider> _BAWP8storageProvider =
    new Lazy<IStorageProvider>(
        () => GetProvider(
            BLL.Providers.ConfigurationProvider.Instance.BAWP8StorageProviderTypeName),
        LazyThreadSafetyMode.ExecutionAndPublication);
private static readonly Lazy<IStorageProvider> _M4MstorageProvider =
    new Lazy<IStorageProvider>(
        () => GetProvider(
            BLL.Providers.ConfigurationProvider.Instance.M4MStorageProviderTypeName),
        LazyThreadSafetyMode.ExecutionAndPublication);

private static IStorageProvider BAStorageProvider
{
    get
    {
        return _BAstorageProvider.Value;
    }
}

private static IStorageProvider BAWP8StorageProvider
{
    get
    {
        return _BAWP8storageProvider.Value;
    }
}

private static IStorageProvider M4MStorageProvider
{
    get
    {
        return _M4MStorageProvider.Value;
    }
}

（但我建议使用依赖容器）

于 2012-08-02T12:40:00.440 回答