//: c10:CADState.java // From Thinking in Java, 2nd Edition // Available at http://www.BruceEckel.com // (c) Bruce Eckel 1999 // Copyright notice in Copyright.txt // Saving and restoring the state of a // pretend CAD system. import java.io.*; import java.util.*; abstract class Shape implements Serializable { public static final int RED = 1, BLUE = 2, GREEN = 3; private int xPos, yPos, dimension; private static Random r = new Random(); private static int counter = 0; abstract public void setColor(int newColor); abstract public int getColor(); public Shape(int xVal, int yVal, int dim) { xPos = xVal; yPos = yVal; dimension = dim; } public String toString() { return getClass().toString() + " color[" + getColor() + "] xPos[" + xPos + "] yPos[" + yPos + "] dim[" + dimension + "]\n"; } public static Shape randomFactory() { int xVal = r.nextInt() % 100; int yVal = r.nextInt() % 100; int dim = r.nextInt() % 100; switch(counter++ % 3) { default: case 0: return new Circle(xVal, yVal, dim); case 1: return new Square(xVal, yVal, dim); case 2: return new Line(xVal, yVal, dim); } } } class Circle extends Shape { private static int color = RED; public Circle(int xVal, int yVal, int dim) { super(xVal, yVal, dim); } public void setColor(int newColor) { color = newColor; } public int getColor() { return color; } } class Square extends Shape { private static int color; public Square(int xVal, int yVal, int dim) { super(xVal, yVal, dim); color = RED; } public void setColor(int newColor) { color = newColor; } public int getColor() { return color; } } class Line extends Shape { private static int color = RED; public static void serializeStaticState(ObjectOutputStream os) throws IOException { os.writeInt(color); } public static void deserializeStaticState(ObjectInputStream os) throws IOException { color = os.readInt(); } public Line(int xVal, int yVal, int dim) { super(xVal, yVal, dim); } public void setColor(int newColor) { color = newColor; } public int getColor() { return color; } } public class CADState { public static void main(String[] args) throws Exception { ArrayList shapeTypes, shapes; if(args.length == 0) { shapeTypes = new ArrayList(); shapes = new ArrayList(); // Add handles to the class objects: shapeTypes.add(Circle.class); shapeTypes.add(Square.class); shapeTypes.add(Line.class); // Make some shapes: for(int i = 0; i < 10; i++) shapes.add(Shape.randomFactory()); // Set all the static colors to GREEN: for(int i = 0; i < 10; i++) ((Shape)shapes.get(i)) .setColor(Shape.GREEN); // Save the state vector: ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream("CADState.out")); out.writeObject(shapeTypes); Line.serializeStaticState(out); out.writeObject(shapes); } else { // There's a command-line argument ObjectInputStream in = new ObjectInputStream( new FileInputStream(args[0])); // Read in the same order they were written: shapeTypes = (ArrayList)in.readObject(); Line.deserializeStaticState(in); shapes = (ArrayList)in.readObject(); } // Display the shapes: System.out.println(shapes); } } ///:~