/// <summary>
/// get the collection of all items, sorted by the provided index.
/// </summary>
/// <param name="ascending"></param>
/// <returns></returns>
public ValueCollection <TKey, TValue> ItemCollection(string indexFieldOrPropertyName, bool ascending)
{
IIndex <TValue> index = this.Indexes.getIndex(indexFieldOrPropertyName);
ValueCollection <TKey, TValue> collection = new ValueCollection <TKey, TValue>(this, index.AllItems(ascending).GetEnumerator());
return(collection);
}
public List <TValue> Take(int count)
{
lock (this.store._Locker)
{
List <TValue> valuelist = new List <TValue>();
if (count == 0)
{
return(valuelist);
}
int skipped = 0;
int taken = 0;
if (string.IsNullOrEmpty(this.OrderByFieldName))
{
// if there is not an order by field, use the primary key.
foreach (TValue item in store.ItemCollection(this.ascending))
{
if (this.predicate(item))
{
if (skipped < this.skip)
{
skipped += 1;
continue;
}
valuelist.Add(item);
taken += 1;
if (taken >= count)
{
return(valuelist);
}
}
}
return(valuelist);
}
else
{
// there is an order by field.
// check whether this is an index or not.
if (store.Indexes.HasIndex(this.OrderByFieldName))
{
IIndex <TValue> index = store.Indexes.getIndex(this.OrderByFieldName);
foreach (Int64 blockposition in index.AllItems(this.ascending))
{
TValue record = store.getValue(blockposition);
if (this.predicate(record))
{
if (skipped < this.skip)
{
skipped += 1;
continue;
}
valuelist.Add(record);
taken += 1;
if (taken >= count)
{
return(valuelist);
}
}
}
return(valuelist);
}
else
{
/// the most expensive and brutal way.
throw new NotImplementedException("order by non-index field is not support yet");
}
}
}
}