Delphi.Omnithreads.Future – hunting the value in backGroundThread

Future is good thread abstraction that hunts for the value in background thread. We can ask backGround thread what is value now.

Calling VCL from backGround is bad idea in that case. For that pupose see

http://www.thedelphigeek.com/2014/07/incrementing-progress-bar-from-foreach.html

Below is example of Future Abstraction From demos…

unit test_39_Futures;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, OtlTask, OtlTaskControl, OtlParallel, Vcl.ComCtrls;

type
  TfrmFuturesDemo = class(TForm)
    btnTestFuture1: TButton;
    lbLog: TListBox;
    btnTestFuture2: TButton;
    btnTestFuture3: TButton;
    btnTestFuture4: TButton;
    btnTestFuture5: TButton;
    btnTestFuture6: TButton;
    btnTestFuture7: TButton;
    bMyFuture: TButton;
    ProgressBar1: TProgressBar;
    procedure FormCreate(Sender: TObject);
    procedure btnTestFuture1Click(Sender: TObject);
    procedure btnTestFuture2Click(Sender: TObject);
    procedure btnTestFuture3Click(Sender: TObject);
    procedure btnTestFuture4Click(Sender: TObject);
    procedure btnTestFuture5Click(Sender: TObject);
    procedure btnTestFuture6Click(Sender: TObject);
    procedure btnTestFuture7Click(Sender: TObject);
    procedure bMyFutureClick(Sender: TObject);
  private
    function CountPrimesTo(high: integer): IOmniFuture<integer>;
    function CountPrimesToHigh(high: integer): integer;
    function CountProgress(high: integer): integer;
    function CountPrimesToMethod: integer;
  public
  end;

var
  frmFuturesDemo: TfrmFuturesDemo;

implementation

uses
  OtlCommon;

{$R *.dfm}
{$I OtlOptions.inc}

const
  CPrimesHigh = 1000000;
  CProgressMax = 100;

function IsPrime(i: integer): boolean;
var
  j: integer;
begin
  Result := false;
  if i <= 1 then
    Exit;
  for j := 2 to Round(Sqrt(i)) do
    if (i mod j) = 0 then
      Exit;
  Result := true;
end;

function CountPrimesToFunc(const task: IOmniTask): integer;
var
  i: integer;
begin
  Result := 0;
  for i := 1 to CPrimesHigh do
    if IsPrime(i) then
    begin
      Inc(Result);
      if task.CancellationToken.IsSignalled then
        Exit;
    end;
end;

procedure TfrmFuturesDemo.FormCreate(Sender: TObject);
begin
  {$IFNDEF Unicode}
  btnTestFuture7.Enabled := false;
  {$ENDIF Unicode}
end;

{ TfrmFuturesDemo }

procedure TfrmFuturesDemo.bMyFutureClick(Sender: TObject);
var
  numPrimes: IOmniFuture<integer>;
begin
  // Use method instead of delegate, test IsDone.
//  numPrimes := TOmniFuture<integer>.Create(CountProgress(100));
 {
  numPrimes := TOmniFuture<integer>.Create(
    function: integer
    begin
      Result := Create(CountProgress(CPrimesHigh));
    end);
  while not numPrimes.IsDone do
  begin
    //Sleep(200);
    ProgressBar1.Position := numPrimes.Value;
    lbLog.Items.Add('in progress ... not yet done');
    lbLog.Update;
  end;
  lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));
  }


  begin
  // Use function-calling delegate.
    numPrimes := TOmniFuture<integer>.Create(
      function: integer
      begin
        Result := CountProgress(CProgressMax);
      end);
//   do something else
    while not numPrimes.IsDone do
    begin
    Sleep(200);
      //ProgressBar1.Position := numPrimes.Value; // bad idea to call vcl from backgroundThread
      // read http://www.thedelphigeek.com/2014/07/incrementing-progress-bar-from-foreach.html
      lbLog.Items.Add('in progress ... not yet done');
      lbLog.Update;
    end;
    lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));
  end;
end;

procedure TfrmFuturesDemo.btnTestFuture1Click(Sender: TObject);
var
  numPrimes: IOmniFuture<integer>;
begin
  // Use future-generating method; call Value twice for testing.
  numPrimes := CountPrimesTo(CPrimesHigh);
//   do something else
  lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));
  lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));
end;

procedure TfrmFuturesDemo.btnTestFuture2Click(Sender: TObject);
var
  numPrimes: IOmniFuture<integer>;
begin
  // Use fully coded delegate, create future twice for testing.
  numPrimes := TOmniFuture<integer>.Create(
    function: integer
    begin
      Result := 0
    end);
  numPrimes := TOmniFuture<integer>.Create(
    function: integer
    var
      i: integer;
    begin
      Result := 0;
      for i := 1 to CPrimesHigh do
        if IsPrime(i) then
          Inc(Result);
    end);
//   do something else
  lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));
end;

procedure TfrmFuturesDemo.btnTestFuture3Click(Sender: TObject);
var
  numPrimes: IOmniFuture<integer>;
begin
  // Use function-calling delegate.
  numPrimes := TOmniFuture<integer>.Create(
    function: integer
    begin
      Result := CountPrimesToHigh(CPrimesHigh);
    end);
//   do something else
  lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));
end;

procedure TfrmFuturesDemo.btnTestFuture4Click(Sender: TObject);
var
  numPrimes: IOmniFuture<integer>;
begin
  // Use method instead of delegate, test IsDone.
  numPrimes := TOmniFuture<integer>.Create(CountPrimesToMethod);
  while not numPrimes.IsDone do
  begin
    Sleep(200);
    lbLog.Items.Add('... not yet done');
    lbLog.Update;
  end;
  lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));
end;

procedure TfrmFuturesDemo.btnTestFuture5Click(Sender: TObject);
var
  numPrimes: IOmniFuture<integer>;
begin
  // Use function instead of delegate, test Cancel, IsCancelled and Value after cancellation (must raise exception).
  numPrimes := TOmniFuture<integer>.CreateEx(CountPrimesToFunc);
  Sleep(200);
  if not numPrimes.IsDone then
  begin
    lbLog.Items.Add('... not yet done, canceling');
    lbLog.Update;
    numPrimes.Cancel;
  end;
  lbLog.Items.Add(Format('... IsCancelled = %s', [BoolToStr(numPrimes.IsCancelled, true)]));
  lbLog.Items.Add(Format('... IsDone = %s', [BoolToStr(numPrimes.IsDone, true)]));
  lbLog.Update;
  lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));
end;

procedure TfrmFuturesDemo.btnTestFuture6Click(Sender: TObject);
var
  countPrimes: integer;
  numPrimes: IOmniFuture<integer>;
begin
  // Test TryValue.
  numPrimes := TOmniFuture<integer>.Create(CountPrimesToMethod);
  while not numPrimes.TryValue(200, countPrimes) do
  begin
    lbLog.Items.Add('... not yet done');
    lbLog.Update;
  end;
  lbLog.Items.Add(Format('%d primes from 1 to %d', [countPrimes, CPrimesHigh]));
end;

procedure TfrmFuturesDemo.btnTestFuture7Click(Sender: TObject);
{$IFDEF Unicode}
var
  numPrimes: IOmniFuture<integer>;
{$ENDIF Unicode}
begin
  {$IFDEF Unicode}
  numPrimes := TOmniFuture<integer>.Create(
    function: integer
    begin
      Result := Parallel.ForEach(1, CPrimesHigh).AggregateSum.Execute(
        procedure(const value: integer; var result: TOmniValue)
        begin
          if IsPrime(value) then
            result := 1;
        end);
    end);
//   do something else
  lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));
  {$ENDIF Unicode}
end;

function TfrmFuturesDemo.CountPrimesTo(high: integer): IOmniFuture<integer>;
begin
  Result := Parallel.Future<integer>(
    function: integer
    var
      i: integer;
    begin
      Result := 0;
      for i := 1 to high do
        if IsPrime(i) then
          Inc(Result);
    end);
end;

function TfrmFuturesDemo.CountPrimesToHigh(high: integer): integer;
var
  i: integer;
begin
  Result := 0;
  for i := 1 to high do
    if IsPrime(i) then
      Inc(Result);
end;

function TfrmFuturesDemo.CountProgress(high: integer): integer;
var
  i: Integer;
begin
  for i := 0 to high - 1 do
  begin
    sleep(500);
    result := i;
  end;
end;

function TfrmFuturesDemo.CountPrimesToMethod: integer;
begin
  Result := CountPrimesToHigh(CPrimesHigh);
end;

end.

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unit test_39_Futures;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, StdCtrls, OtlTask, OtlTaskControl, OtlParallel, Vcl.ComCtrls;

type

TfrmFuturesDemo = class(TForm)

btnTestFuture1: TButton;

lbLog: TListBox;

btnTestFuture2: TButton;

btnTestFuture3: TButton;

btnTestFuture4: TButton;

btnTestFuture5: TButton;

btnTestFuture6: TButton;

btnTestFuture7: TButton;

bMyFuture: TButton;

ProgressBar1: TProgressBar;

procedure FormCreate(Sender: TObject);

procedure btnTestFuture1Click(Sender: TObject);

procedure btnTestFuture2Click(Sender: TObject);

procedure btnTestFuture3Click(Sender: TObject);

procedure btnTestFuture4Click(Sender: TObject);

procedure btnTestFuture5Click(Sender: TObject);

procedure btnTestFuture6Click(Sender: TObject);

procedure btnTestFuture7Click(Sender: TObject);

procedure bMyFutureClick(Sender: TObject);

private

function CountPrimesTo(high: integer): IOmniFuture<integer>;

function CountPrimesToHigh(high: integer): integer;

function CountProgress(high: integer): integer;

function CountPrimesToMethod: integer;

public

end;

var

frmFuturesDemo: TfrmFuturesDemo;

implementation

uses

OtlCommon;

{$R *.dfm}

{$I OtlOptions.inc}

const

CPrimesHigh = 1000000;

CProgressMax = 100;

function IsPrime(i: integer): boolean;

var

j: integer;

begin

Result := false;

if i <= 1 then

Exit;

for j := 2 to Round(Sqrt(i)) do

if (i mod j) = 0 then

Exit;

Result := true;

end;

function CountPrimesToFunc(const task: IOmniTask): integer;

var

i: integer;

begin

Result := 0;

for i := 1 to CPrimesHigh do

if IsPrime(i) then

begin

Inc(Result);

if task.CancellationToken.IsSignalled then

Exit;

end;

procedure TfrmFuturesDemo.FormCreate(Sender: TObject);

begin

{$IFNDEF Unicode}

btnTestFuture7.Enabled := false;

{$ENDIF Unicode}

end;

{ TfrmFuturesDemo }

procedure TfrmFuturesDemo.bMyFutureClick(Sender: TObject);

var

numPrimes: IOmniFuture<integer>;

begin

// Use method instead of delegate, test IsDone.

// numPrimes := TOmniFuture<integer>.Create(CountProgress(100));

{

numPrimes := TOmniFuture<integer>.Create(

function: integer

begin

Result := Create(CountProgress(CPrimesHigh));

end);

while not numPrimes.IsDone do

begin

//Sleep(200);

ProgressBar1.Position := numPrimes.Value;

lbLog.Items.Add('in progress ... not yet done');

lbLog.Update;

end;

lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));

}

begin

// Use function-calling delegate.

numPrimes := TOmniFuture<integer>.Create(

function: integer

begin

Result := CountProgress(CProgressMax);

end);

// do something else

while not numPrimes.IsDone do

begin

Sleep(200);

//ProgressBar1.Position := numPrimes.Value; // bad idea to call vcl from backgroundThread

// read http://www.thedelphigeek.com/2014/07/incrementing-progress-bar-from-foreach.html

lbLog.Items.Add('in progress ... not yet done');

lbLog.Update;

end;

lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));

end;

procedure TfrmFuturesDemo.btnTestFuture1Click(Sender: TObject);

var

numPrimes: IOmniFuture<integer>;

begin

// Use future-generating method; call Value twice for testing.

numPrimes := CountPrimesTo(CPrimesHigh);

// do something else

lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));

end;

procedure TfrmFuturesDemo.btnTestFuture2Click(Sender: TObject);

var

numPrimes: IOmniFuture<integer>;

begin

// Use fully coded delegate, create future twice for testing.

numPrimes := TOmniFuture<integer>.Create(

function: integer

begin

Result := 0

end);

numPrimes := TOmniFuture<integer>.Create(

function: integer

var

i: integer;

begin

Result := 0;

for i := 1 to CPrimesHigh do

if IsPrime(i) then

Inc(Result);

end);

// do something else

lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));

end;

procedure TfrmFuturesDemo.btnTestFuture3Click(Sender: TObject);

var

numPrimes: IOmniFuture<integer>;

begin

// Use function-calling delegate.

numPrimes := TOmniFuture<integer>.Create(

function: integer

begin

Result := CountPrimesToHigh(CPrimesHigh);

end);

// do something else

lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));

end;

procedure TfrmFuturesDemo.btnTestFuture4Click(Sender: TObject);

var

numPrimes: IOmniFuture<integer>;

begin

// Use method instead of delegate, test IsDone.

numPrimes := TOmniFuture<integer>.Create(CountPrimesToMethod);

while not numPrimes.IsDone do

begin

Sleep(200);

lbLog.Items.Add('... not yet done');

lbLog.Update;

end;

lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));

end;

procedure TfrmFuturesDemo.btnTestFuture5Click(Sender: TObject);

var

numPrimes: IOmniFuture<integer>;

begin

// Use function instead of delegate, test Cancel, IsCancelled and Value after cancellation (must raise exception).

numPrimes := TOmniFuture<integer>.CreateEx(CountPrimesToFunc);

Sleep(200);

if not numPrimes.IsDone then

begin

lbLog.Items.Add('... not yet done, canceling');

lbLog.Update;

numPrimes.Cancel;

end;

lbLog.Items.Add(Format('... IsCancelled = %s', [BoolToStr(numPrimes.IsCancelled, true)]));

lbLog.Items.Add(Format('... IsDone = %s', [BoolToStr(numPrimes.IsDone, true)]));

lbLog.Update;

lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));

end;

procedure TfrmFuturesDemo.btnTestFuture6Click(Sender: TObject);

var

countPrimes: integer;

numPrimes: IOmniFuture<integer>;

begin

// Test TryValue.

numPrimes := TOmniFuture<integer>.Create(CountPrimesToMethod);

while not numPrimes.TryValue(200, countPrimes) do

begin

lbLog.Items.Add('... not yet done');

lbLog.Update;

end;

lbLog.Items.Add(Format('%d primes from 1 to %d', [countPrimes, CPrimesHigh]));

end;

procedure TfrmFuturesDemo.btnTestFuture7Click(Sender: TObject);

{$IFDEF Unicode}

var

numPrimes: IOmniFuture<integer>;

{$ENDIF Unicode}

begin

{$IFDEF Unicode}

numPrimes := TOmniFuture<integer>.Create(

function: integer

begin

Result := Parallel.ForEach(1, CPrimesHigh).AggregateSum.Execute(

procedure(const value: integer; var result: TOmniValue)

begin

if IsPrime(value) then

result := 1;

end);

// do something else

lbLog.Items.Add(Format('%d primes from 1 to %d', [numPrimes.Value, CPrimesHigh]));

{$ENDIF Unicode}

end;

function TfrmFuturesDemo.CountPrimesTo(high: integer): IOmniFuture<integer>;

begin

Result := Parallel.Future<integer>(

function: integer

var

i: integer;

begin

Result := 0;

for i := 1 to high do

if IsPrime(i) then

Inc(Result);

end);

end;

function TfrmFuturesDemo.CountPrimesToHigh(high: integer): integer;

var

i: integer;

begin

Result := 0;

for i := 1 to high do

if IsPrime(i) then

Inc(Result);

end;

function TfrmFuturesDemo.CountProgress(high: integer): integer;

var

i: Integer;

begin

for i := 0 to high - 1 do

begin

sleep(500);

result := i;

end;

function TfrmFuturesDemo.CountPrimesToMethod: integer;

begin

Result := CountPrimesToHigh(CPrimesHigh);

end;

end.

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