/// <summary>
/// <para>Initializes a new instance of the <see cref="CursorEnumerator{T, THeader}"/>
/// class.</para>
/// </summary>
/// <param name="list">
/// <para>The underlying cursor based <see cref="ObjectListForMultiples{T, THeader}"/>.</para>
/// </param>
public CursorEnumerator(ObjectListForMultiples <T, THeader> list)
{
_list = list;
var dummy = new byte[1];
if (_list.Cursor.Get(dummy, true) < 0)
{
throw new ApplicationException("No header");
}
}
/// <summary>
/// <para>Gets a list of objects from the store, or creates one if the list is not found.</para>
/// </summary>
/// <typeparam name="T">
/// <para>The type of the objects in the list.</para>
/// </typeparam>
/// <typeparam name="THeader">
/// <para>The type of the list's header information.</para>
/// </typeparam>
/// <param name="keySpace">
/// <para>The key space of the list.</para>
/// </param>
/// <param name="key">
/// <para>The key of the list.</para>
/// </param>
/// <param name="header">
/// <para>A<typeparamref name="THeader"/> containing the
/// list's header information.</para></param>
/// <param name="expires">
/// <para>The expiration <see cref="DateTime"/> to use if the list must be created.</para>
/// </param>
/// <param name="creator">
/// <para>Delegate that provides an empty instance for stores that use
/// serialization. May be <see langword="null"/> for stores if
/// serialization not used or if store can create empty instances of
/// <typeparamref name="T"/> on its own.</para>
/// </param>
/// <param name="headerCreator">
/// <para>Delegate that provides an empty header instance for stores that use
/// serialization. May be <see langword="null"/> for stores if
/// serialization not used or if store can create empty instances of
/// <typeparamref name="THeader"/> on its own.</para>
/// </param>
/// <returns>
/// <para>The <see cref="StorageEntry{IObjectList}"/> read or created.</para>
/// </returns>
public StorageEntry <IObjectList <T, THeader> > GetOrCreateList <T, THeader>(DataBuffer keySpace, StorageKey key, THeader header, DateTime expires,
Func <T> creator, Func <THeader> headerCreator)
{
AddKeySpaceInfoForList <T, THeader>(keySpace);
var allowsMultiple = Storage.GetAllowsMultiple(keySpace);
IObjectList <T, THeader> list;
if (Storage.Exists(keySpace, key))
{
if (allowsMultiple)
{
var objectList = new ObjectListForMultiples <T, THeader>(this,
keySpace, key, creator, headerCreator);
expires = objectList.Expires;
list = objectList;
}
else
{
var objectList = new ObjectListForSingles <T, THeader>(this,
keySpace, key, DataBuffer.Empty, creator, headerCreator);
expires = objectList.Expires;
list = objectList;
}
}
else
{
if (allowsMultiple)
{
list = new ObjectListForMultiples <T, THeader>(this,
keySpace, key, creator, header, expires);
}
else
{
list = new ObjectListForSingles <T, THeader>(this,
keySpace, key, creator, header, expires);
}
}
return(new StorageEntry <IObjectList <T, THeader> >(list,
DateTime.MinValue, expires));
}
/// <summary>
/// <para>Gets a list of objects from the store.</para>
/// </summary>
/// <typeparam name="T">
/// <para>The type of the objects in the list.</para>
/// </typeparam>
/// <typeparam name="THeader">
/// <para>The type of the list's header information.</para>
/// </typeparam>
/// <param name="keySpace">
/// <para>The key space of the list.</para>
/// </param>
/// <param name="key">
/// <para>The key of the list.</para>
/// </param>
/// <param name="creator">
/// <para>Delegate that provides an empty instance for stores that use
/// serialization. May be <see langword="null"/> for stores if
/// serialization not used or if store can create empty instances of
/// <typeparamref name="T"/> on its own.</para>
/// </param>
/// <param name="headerCreator">
/// <para>Delegate that provides an empty header instance for stores that use
/// serialization. May be <see langword="null"/> for stores if
/// serialization not used or if store can create empty instances of
/// <typeparamref name="THeader"/> on its own.</para>
/// </param>
/// <returns>
/// <para>The <see cref="StorageEntry{IObjectList}"/> containing the fetched list.</para>
/// </returns>
public StorageEntry <IObjectList <T, THeader> > GetList <T, THeader>(DataBuffer keySpace, StorageKey key,
Func <T> creator, Func <THeader> headerCreator)
{
AddKeySpaceInfoForList <T, THeader>(keySpace);
if (!Storage.Exists(keySpace, key))
{
return(StorageEntry <IObjectList <T, THeader> > .NotFound);
}
if (Storage.GetAllowsMultiple(keySpace))
{
var list = new ObjectListForMultiples <T, THeader>(this,
keySpace, key, creator, headerCreator);
return(new StorageEntry <IObjectList <T, THeader> >(list,
DateTime.MinValue, list.Expires));
}
else
{
var list = new ObjectListForSingles <T, THeader>(this,
keySpace, key, DataBuffer.Empty, creator, headerCreator);
return(new StorageEntry <IObjectList <T, THeader> >(list,
DateTime.MinValue, list.Expires));
}
}
/// <summary>
/// <para>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</para>
/// </summary>
public void Dispose()
{
_list.ClearCursor();
_list = null;
}
