Initial commit for 4.1

src/main/java/_4/_1/Function.java

@@ -0,0 +1,23 @@
+package _4._1;
+
+public abstract class Function {
+
+	protected Function predecessor;
+
+	public Function() {
+		this.predecessor = null;
+	}
+
+	public Function(Function predecessor) {
+		this.predecessor = predecessor;
+	}
+
+	public double calculate(double x) {
+		if(this.predecessor == null) {
+			return this.apply(x);
+		}
+		return this.predecessor.calculate(x);
+	}
+
+	protected abstract double apply(double x);
+}

src/main/java/_4/_1/SineFunction.java

@@ -0,0 +1,16 @@
+package _4._1;
+
+public class SineFunction extends Function {
+	public SineFunction() {
+		super();
+	}
+
+	public SineFunction(Function predecessor) {
+		super(predecessor);
+	}
+
+	@Override
+	public double apply(double x) {
+		return Math.sin(x);
+	}
+}

src/main/java/_4/_1/SquareFunction.java

@@ -0,0 +1,16 @@
+package _4._1;
+
+public class SquareFunction extends Function {
+	public SquareFunction() {
+		super();
+	}
+
+	public SquareFunction(Function predecessor) {
+		super(predecessor);
+	}
+
+	@Override
+	protected double apply(double x) {
+		return x * x;
+	}
+}