//: reusing/CADSystem.java
// Ensuring proper cleanup.
package reusing; //如果注释掉这一行则可以正常运行
import static net.gondi.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 dispose() {
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 CADSystem extends Shape {
private Circle c;
private Triangle t;
private Line[] lines = new Line[3];
public CADSystem(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) {
CADSystem x = new CADSystem(47);
try {
// Cond and exception handling...
}
finally {
x.dispose();
}
}
}