// Unity C# reference source

// Copyright (c) Unity Technologies. For terms of use, see

// https://unity3d.com/legal/licenses/Unity_Reference_Only_License

using System;

using System.Collections.Generic;

using System.Linq;

namespace UnityEditor.Experimental.UIElements.GraphView

{

public abstract class BaseTypeFactory<TKey, TValue>

{

private readonly Dictionary<Type, Type> m_Mappings = new Dictionary<Type, Type>();

private readonly Type m_FallbackType;

private static readonly Type k_KeyType;

private static readonly Type k_ValueType;

static BaseTypeFactory()

{

k_KeyType = typeof(TKey);

k_ValueType = typeof(TValue);

}

public Type this[Type t]

{

get

{

try

{

return m_Mappings[t];

}

catch (KeyNotFoundException e)

{

throw new KeyNotFoundException("Type " + t.Name + " is not registered in the factory.", e);

}

}

set

{

if (!t.IsSubclassOf(k_KeyType) && !t.GetInterfaces().Contains(k_KeyType))

{

throw new ArgumentException("The type passed as key (" + t.Name + ") does not implement or derive from " + k_KeyType.Name + ".");

}

if (!value.IsSubclassOf(k_ValueType))

{

throw new ArgumentException("The type passed as value (" + value.Name + ") does not derive from " + k_ValueType.Name + ".");

}

m_Mappings[t] = value;

}

}

public virtual TValue Create(TKey key)

{

Type valueType = null;

Type keyType = key.GetType();

while (valueType == null && keyType != null && keyType != typeof(TKey))

{

if (!m_Mappings.TryGetValue(keyType, out valueType))

{

keyType = keyType.BaseType;

}

}

if (valueType == null)

{

valueType = m_FallbackType;

}

return InternalCreate(valueType);

}

protected BaseTypeFactory()

: this(typeof(TValue))

{}

protected BaseTypeFactory(Type fallbackType)

{

m_FallbackType = fallbackType;

}

protected virtual TValue InternalCreate(Type valueType)

{

return (TValue)Activator.CreateInstance(valueType);

}

}

}