Data commit

Task/Active-object/Groovy/active-object.groovy

@@ -0,0 +1,70 @@
+/**
+ * Integrates input function K over time
+ * S + (t1 - t0) * (K(t1) + K(t0)) / 2
+ */
+class Integrator {
+    interface Function {
+        double apply(double timeSinceStartInSeconds)
+    }
+
+    private final long start
+    private volatile boolean running
+
+    private Function func
+    private double t0
+    private double v0
+    private double sum
+
+    Integrator(Function func) {
+        this.start = System.nanoTime()
+        setFunc(func)
+        new Thread({ this.&integrate() }).start()
+    }
+
+    void setFunc(Function func) {
+        this.func = func
+        def temp = func.apply(0.0.toDouble())
+        v0 = temp
+        t0 = 0.0.doubleValue()
+    }
+
+    double getOutput() {
+        return sum
+    }
+
+    void stop() {
+        running = false
+    }
+
+    private void integrate() {
+        running = true
+        while (running) {
+            try {
+                Thread.sleep(1)
+                update()
+            } catch (InterruptedException ignored) {
+                return
+            }
+        }
+    }
+
+    private void update() {
+        double t1 = (System.nanoTime() - start) / 1.0e9
+        double v1 = func.apply(t1)
+        double rect = (t1 - t0) * (v0 + v1) / 2.0
+        this.sum += rect
+        t0 = t1
+        v0 = v1
+    }
+
+    static void main(String[] args) {
+        Integrator integrator = new Integrator({ t -> Math.sin(Math.PI * t) })
+        Thread.sleep(2000)
+
+        integrator.setFunc({ t -> 0.0.toDouble() })
+        Thread.sleep(500)
+
+        integrator.stop()
+        System.out.println(integrator.getOutput())
+    }
+}