program System_Collections_DictionaryBase;
{$APPTYPE CONSOLE}
{$AUTOBOX ON}

uses System.Collections;

type
  ShortStringDictionary = class(DictionaryBase)
  public
    function get_Keys: ICollection;
    function get_Values: ICollection;
    function get_Items(key: string): string;
    procedure set_Items(key: string; const Value: string);

    procedure Add(key: string; value: string);
    function Contains(key: string): Boolean;
    procedure Remove(key: string);

    property Items[key: string]: string 
             read get_Items 
             write set_Items; 
             default;
    property Keys: ICollection read get_Keys;
    property Values: ICollection read get_Values;
  strict protected
    procedure OnInsert(key: System.Object; 
                       value: System.Object); override;
    procedure OnRemove(key: System.Object; 
                       value: System.Object); override;
    procedure OnSet(key: System.Object; 
                    oldValue: System.Object; 
                    newValue: System.Object); override;
    procedure OnValidate(key: System.Object; 
                         value: System.Object); override;
  end;

  SamplesDictionaryBase = class
  public
    class procedure Main;
  private
    class procedure PrintKeysAndValues
                 (myCol: ShortStringDictionary);
  end;

{ ShortStringDictionary }

procedure ShortStringDictionary.Add(key, value: string);
begin
  Dictionary.Add(key, value);
end;

function ShortStringDictionary.Contains(key: string): Boolean;
begin
  Result := Dictionary.Contains(key);
end;

function ShortStringDictionary.get_Items(key: string): string;
begin
  Result := (string(Dictionary[key]));
end;

function ShortStringDictionary.get_Keys: ICollection;
begin
  Result := Dictionary.Keys;
end;

function ShortStringDictionary.get_Values: ICollection;
begin
  Result := Dictionary.Values;
end;

procedure ShortStringDictionary.OnInsert(key, value: System.Object);
var
  strValue: string;
  strKey: string;
begin
  if (key.GetType <> System.Type.GetType('System.String')) then
    raise ArgumentException.Create
          ('key must be of type String.', 'key')
  else
  begin
    strKey := (string(key));
    if (strKey.Length > 5) then
      raise ArgumentException.Create
            ('key must be no more than 5 characters in length.',
             'key');
  end;

  if (value.GetType <> System.Type.GetType('System.String')) then
    raise ArgumentException.Create
          ('value must be of type String.', 'value')
  else
  begin
    strValue := (string(value));
    if (strValue.Length > 5) then
      raise ArgumentException.Create
            ('value must be no more than 5 characters in length.',
             'value');
  end;
end;

procedure ShortStringDictionary.OnRemove(key, value: System.Object);
var
  strKey: string;
begin
  if (key.GetType <> System.Type.GetType('System.String')) then
    raise ArgumentException.Create
          ('key must be of type String.', 
           'key')
  else
  begin
    strKey := (string(key));
    if (strKey.Length > 5) then
      raise ArgumentException.Create
            ('key must be no more than 5 characters in length.', 
             'key');
  end;
end;

procedure ShortStringDictionary.OnSet
          (key, oldValue, newValue: System.Object);
var
  strValue: string;
  strKey: string;
begin
  if (key.GetType <> System.Type.GetType('System.String')) then
    raise ArgumentException.Create
          ('key must be of type String.', 'key')
  else
  begin
    strKey := (string(key));
    if (strKey.Length > 5) then
      raise ArgumentException.Create
            ('key must be no more than 5 characters in length.', 
             'key');
  end;
  if (newValue.GetType <> System.Type.GetType('System.String')) then
    raise ArgumentException.Create
          ('newValue must be of type String.', 
           'newValue')
  else
  begin
    strValue := (string(newValue));
    if (strValue.Length > 5) then
      raise ArgumentException.Create
            ('newValue must be no more 
              than 5 characters in length.', 
             'newValue');
  end;
end;

procedure ShortStringDictionary.OnValidate(key, value: System.Object);
var
  strValue: string;
  strKey: string;
begin
  if (key.GetType <> System.Type.GetType('System.String')) then
    raise ArgumentException.Create
         ('key must be of type String.', 
          'key')
  else
  begin
    strKey := (string(key));
    if (strKey.Length > 5) then
      raise ArgumentException.Create
            ('key must be no more than 
              5 characters in length.', 
             'key');
  end;
  if (value.GetType <> System.Type.GetType('System.String')) then
    raise ArgumentException.Create
          ('value must be of type String.', 
           'value')
  else
  begin
    strValue := (string(value));
    if (strValue.Length > 5) then
      raise ArgumentException.Create
           ('value must be no more than 
             5 characters in length.', 
            'value');
  end;
end;

procedure ShortStringDictionary.Remove(key: string);
begin
  Dictionary.Remove(key);
end;

procedure ShortStringDictionary.set_Items
          (key: string; const Value: string);
begin
  Dictionary[key] := value;
end;

{ SamplesDictionaryBase }

class procedure SamplesDictionaryBase.Main;
var
  mySSC: ShortStringDictionary;
begin
  // Creates and initializes a new DictionaryBase
  mySSC := ShortStringDictionary.Create;

  // Adds elements to the collection
  mySSC.Add('One', 'a');
  mySSC.Add('Two', 'ab');
  mySSC.Add('Three', 'abc');
  mySSC.Add('Four', 'abcd');
  mySSC.Add('Five', 'abcde');

  // Tries to add a value that is too long
  try
    mySSC.Add('Ten', 'abcdefghij');
  except
    on e: ArgumentException do
      Console.WriteLine(e.ToString);
  end;

  // Tries to add a key that is too long
  try
    mySSC.Add('Eleven', 'ijk');
  except
    on e: ArgumentException do
      Console.WriteLine(e.ToString);
  end;
  Console.WriteLine;

  // Displays the contents of the 
  //collection using the enumerator
  Console.WriteLine('Initial contents of the collection:');
  PrintKeysAndValues(mySSC);

  // Searches the collection with Contains.
  Console.WriteLine('Contains "Three": {0}', mySSC.Contains('Three'));
  Console.WriteLine('Contains "Twelve": {0}', mySSC.Contains('Twelve'));
  Console.WriteLine;

  // Removes an element from the collection
  mySSC.Remove('Two');
  Console.WriteLine('New state of the collection:');

  PrintKeysAndValues(mySSC);
end;

class procedure SamplesDictionaryBase.PrintKeysAndValues
                (myCol: ShortStringDictionary);
var
  myEnumerator: System.Collections.IEnumerator;
  myDE: DictionaryEntry;
begin
  myEnumerator := myCol.GetEnumerator;
  while myEnumerator.MoveNext do
  begin
    if (myEnumerator.Current <> nil) then
    begin
      myDE := (DictionaryEntry(myEnumerator.Current));
      Console.WriteLine('   {0,-5} : {1}', 
                        myDE.Key, 
                        myDE.Value);
    end;
  end;
  Console.WriteLine;
end;

//test program
begin
  SamplesDictionaryBase.Main;
end.