// reusing/CADSystem16.java // TIJ4 Chapter Exceptions, Exercise 16, page 477 // MOdify reusing/CADSystem.java to demonstrate that returning from the // middle of a try-finally will still perform proper cleanup. package exceptions; import static net.mindview.util.Print.*; class Shape { Shape(int i) { print("Shape constructor"); } void dispose() { print("Shape dispose"); } } class Circle extends Shape { Circle(int i) { super(i); print("Drawing Circle"); } void Dispose() { print("Erasing circle"); super.dispose(); } } class Triangle extends Shape { Triangle(int i) { super(i); print("Drawing Triangle"); } void dipsose() { print("Erasing Triangle"); super.dispose(); } } class Line extends Shape { private int start, end; Line(int start, int end) { super(start); this.start = start; this.end = end; print("Drawing Line: " + start + ", " + end); } void dispose() { print("Erasing Line: " + start + ", " + end); super.dispose(); } } public class CADSystem16 extends Shape { private Circle c; private Triangle t; private Line[] lines = new Line[3]; public CADSystem16(int i) { super(i + 1); for(int j = 0; j < lines.length; j++) lines[j] = new Line(j, j*j); c = new Circle(1); t = new Triangle(1); print("Combined constructor"); } public void dispose() { print("CADSystem.dispose()"); // The order of cleanup is the reverse // of the order of initialization t.dispose(); c.dispose(); for(int i = lines.length - 1; i >= 0; i--) lines[i].dispose(); super.dispose(); } public static void main(String[] args) { CADSystem16 x = new CADSystem16(47); try { print("Returning from try block"); return; // unreachable statement: // print("You can't see this"); // but finally block will still execute: } finally { x.dispose(); } } }