/// <summary>
/// Get an associate given an indexing object
/// </summary>
/// <param name='key'>
/// The object to find the associate for
/// </param>
/// <typeparam name='T2'>
/// The type of associate to find
/// </typeparam>
public T2 Get <T2>(object key, Func <object> t2Factory) where T2 : T
{
//Get the hash code of the indexing object
int hash = key.GetHashCode();
List <WeakEntry> entries;
//See if we have a reference already
if (!references.TryGetValue(hash, out entries))
{
//If not the create the reference list
references[hash] = entries = new List <WeakEntry>();
}
//See if we have an object of the correct type and that the
//reference is still alive
WeakEntry item = entries.FirstOrDefault(e => e.weakReference.IsAlive && e.weakReference.Target == key && e.associate is T2);
if (item == null)
{
//If not create one
if (t2Factory != null)
{
entries.Add(item = new WeakEntry {
weakReference = new WeakReference(key), associate = t2Factory()
});
}
else
{
return(default(T2));
}
}
//Return the associate
return((T2)item.associate);
}
/// <summary>
/// Gets an associated object give an index of another object
/// </summary>
/// <param name='index'>
/// The object to use as an index
/// </param>
public T this[object key]
{
get
{
//Get the hash code of the indexed object
int hash = key.GetHashCode();
//Try to get a reference to it
List <WeakEntry> entries;
if (!references.TryGetValue(hash, out entries))
{
//If we failed then create a new entry
references[hash] = entries = new List <WeakEntry>();
}
//Try to get an associated object of the right type for this
//indexer/make sure it is still alive
WeakEntry item = entries.FirstOrDefault(e => e.weakReference.IsAlive && e.weakReference.Target == key);
//Check if we got one
if (item == null)
{
//If we didn't then create a new one
if (factory != null)
{
entries.Add(item = new WeakEntry {
weakReference = new WeakReference(key), associate = factory()
});
}
else
{
return(null);
}
}
//Return the associated object
return((T)item.associate);
}
}
