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using System;
namespace Apewer
{
/// <summary>装箱类。</summary>
public sealed class Class<T> // : IComparable, IComparable<T>, IComparable<Class<T>>
{
/// <summary>值。</summary>
public T Value { get; set; }
/// <summary>创建装箱实例,值为默认值。</summary>
public Class() { }
/// <summary>创建装箱实例,值为指定值。</summary>
public Class(T value) => Value = value;
#region Override
/// <summary></summary>
public override int GetHashCode()
{
if (Value != null) return Value.GetHashCode();
return base.GetHashCode();
}
/// <summary></summary>
public override bool Equals(object obj)
{
if (ReferenceEquals(this, obj)) return true;
var right = obj as Class<T>;
if (Value.IsNull())
{
if (right == null) return true;
if (right.Value.IsNull()) return true;
return false;
}
else
{
if (right == null) return false;
if (right.Value.IsNull()) return false;
if (ReferenceEquals(Value, right.Value)) return true;
return Value.Equals(right.Value);
}
}
/// <summary></summary>
public override string ToString()
{
if (Value == null) return null;
return Value.ToString();
}
#endregion
#if ClassCompare
#region Compare
/// <summary></summary>
/// <exception cref="NotSupportedException"></exception>
public int CompareTo(object obj)
{
if (typeof(IComparable).IsAssignableFrom(typeof(T)))
{
var comparable = Value as IComparable;
if (comparable.IsNull())
{
if (obj is Class<T> bro)
{
if (bro == null) return 0;
if (bro.Value.IsNull()) return 0;
return -1;
}
if (obj.IsNull()) return 0;
return -1;
}
else
{
if (obj != null && obj is Class<T> bro) return comparable.CompareTo(bro.Value);
return comparable.CompareTo(obj);
}
}
throw new NotImplementedException($"类型 {typeof(T).Name} 没有实现 {nameof(IComparable)} 接口。");
}
/// <summary></summary>
/// <exception cref="MissingMemberException"></exception>
/// <exception cref="NotSupportedException"></exception>
public int CompareTo(T other)
{
if (Value == null) throw new MissingMemberException(typeof(T).FullName, nameof(Value));
if (!(Value is IComparable)) throw new NotSupportedException();
return ((IComparable<T>)Value).CompareTo(other);
}
/// <summary></summary>
/// <exception cref="MissingMemberException"></exception>
/// <exception cref="NotSupportedException"></exception>
public int CompareTo(Class<T> other)
{
if (Value == null) throw new MissingMemberException(typeof(T).FullName, nameof(Value));
if (Value is IComparable) return ((IComparable)Value).CompareTo(other.Value);
if (Value is IComparable<T>) return ((IComparable<T>)Value).CompareTo(other.Value);
throw new NotSupportedException();
}
#endregion
#endif
#region 运算符。
/// <summary>从 <see cref="Class{T}"/> 到 Boolean 的隐式转换,判断 <see cref="Class{T}"/> 包含值。</summary>
/// <remarks>当 T 是 Boolean 时,获取 Value。<br />当 T 是 String 时,判断 Value 不为 NULL 且不为空。</remarks>
public static implicit operator bool(Class<T> instance)
{
if (instance == null) return false;
// var boolean = instance as Class<bool>;
// if (boolean != null) return boolean.Value;
// var text = instance as Class<string>;
// if (text != null) return !string.IsNullOrEmpty(text.Value);
return true;
}
// /// <summary>从 <see cref="Class{T}"/> 到 T 的隐式转换。</summary>
// public static implicit operator T(Class<T> instance)
// {
// if (instance == null) return default(T);
// if (typeof(T).Equals(typeof(bool))) return instance.Value;
// return instance.Value;
// }
// /// <summary>从 T 到 <see cref="Class{T}"/> 的隐式转换。</summary>
// public static implicit operator Class<T>(T value) => new Class<T>(value);
#endregion
}
}