Data commit

Task/Active-object/Delphi/active-object.delphi

@@ -0,0 +1,86 @@
+program Active_object;
+
+{$APPTYPE CONSOLE}
+
+uses
+  System.SysUtils,
+  System.Classes;
+
+type
+  TIntegrator = class(TThread)
+  private
+    { Private declarations }
+    interval, s: double;
+    IsRunning: Boolean;
+  protected
+    procedure Execute; override;
+  public
+    k: Tfunc<Double, Double>;
+    constructor Create(k: Tfunc<Double, Double>; inteval: double = 1e-4); overload;
+    procedure Join;
+  end;
+
+{ TIntegrator }
+
+constructor TIntegrator.Create(k: Tfunc<Double, Double>; inteval: double = 1e-4);
+begin
+  self.interval := Interval;
+  self.K := k;
+  self.S := 0.0;
+  IsRunning := True;
+  FreeOnTerminate := True;
+  inherited Create(false);
+end;
+
+procedure TIntegrator.Execute;
+var
+  interval, t0, k0, t1, k1: double;
+  start: Cardinal;
+begin
+  inherited;
+
+  interval := self.interval;
+  start := GetTickCount;
+  t0 := 0;
+  k0 := self.K(0);
+
+  while IsRunning do
+  begin
+    t1 := (GetTickCount - start) / 1000;
+    k1 := self.K(t1);
+    self.S := self.S + ((k1 + k0) * (t1 - t0) / 2.0);
+    t0 := t1;
+    k0 := k1;
+  end;
+end;
+
+procedure TIntegrator.Join;
+begin
+  IsRunning := false;
+end;
+
+var
+  Integrator: TIntegrator;
+
+begin
+  Integrator := TIntegrator.create(
+    function(t: double): double
+    begin
+      Result := sin(pi * t);
+    end);
+
+  sleep(2000);
+
+  Writeln(Integrator.s);
+
+  Integrator.k :=
+    function(t: double): double
+    begin
+      Result := 0;
+    end;
+
+  sleep(500);
+  Writeln(Integrator.s);
+  Integrator.Join;
+  Readln;
+end.