TSortedCollection object

In unit Objects

Abstract sorted collection.

Declaration

pascal

TSortedCollection = class(TCollection)

Inheritance

TSortedCollection
TCollection
TPersistent
TObject

Descends from it: TStrCollection TStringCollection

Description

TSortedCollection is an abstract class, implementing a sorted collection. You should never use an instance of TSortedCollection directly, instead you should declare a descendent type, and override the Compare method.

Because the collection is ordered, TSortedCollection overrides some TCollection methods, to provide faster routines for lookup.

The Compare method decides how elements in the collection should be ordered. Since TCollection has no way of knowing how to order pointers, you must override the compare method.

Additionally, TCollection provides a means to filter out duplicates. if you set Duplicates to False (the default) then duplicates will not be allowed.

The example below defines a descendent of TSortedCollection which is used in the examples.

Example: `mysortc`

pascal

Unit MySortC;

Interface

Uses Objects;

Type
  PMySortedCollection = ^TMySortedCollection;
  TMySortedCollection = Object(TSortedCollection)
       Function Compare (Key1,Key2 : Pointer): Sw_integer; virtual;
       end;

Implementation

Uses MyObject;

Function TMySortedCollection.Compare (Key1,Key2 : Pointer) :sw_integer;

begin
  Compare:=PMyobject(Key1)^.GetField - PMyObject(Key2)^.GetField;
end;

end.

Methods

`Init`		Instantiates a new instance of a TSortedCollection.
`Load`		Instantiates a new instance of a TSortedCollection and loads it from stream.
`KeyOf`		Return the key of an item.
`IndexOf`		Return index of an item in the collection.
`Compare`		Compare two items in the collection.
`Search`		Search for item with given key.
`Insert`		Insert new item in collection.
`Store`		Write the collection to the stream.