FileDocCategorySizeDatePackage
CADState.javaAPI DocExample5843Mon Apr 06 18:10:24 BST 1998None

CADState.java

//: CADState.java
//////////////////////////////////////////////////
// Copyright (c) Bruce Eckel, 1998
// Source code file from the book "Thinking in Java"
// All rights reserved EXCEPT as allowed by the
// following statements: You can freely use this file
// for your own work (personal or commercial),
// including modifications and distribution in
// executable form only. Permission is granted to use
// this file in classroom situations, including its
// use in presentation materials, as long as the book
// "Thinking in Java" is cited as the source. 
// Except in classroom situations, you cannot copy
// and distribute this code; instead, the sole
// distribution point is http://www.BruceEckel.com 
// (and official mirror sites) where it is
// freely available. You cannot remove this
// copyright and notice. You cannot distribute
// modified versions of the source code in this
// package. You cannot use this file in printed
// media without the express permission of the
// author. Bruce Eckel makes no representation about
// the suitability of this software for any purpose.
// It is provided "as is" without express or implied
// warranty of any kind, including any implied
// warranty of merchantability, fitness for a
// particular purpose or non-infringement. The entire
// risk as to the quality and performance of the
// software is with you. Bruce Eckel and the
// publisher shall not be liable for any damages
// suffered by you or any third party as a result of
// using or distributing software. In no event will
// Bruce Eckel or the publisher be liable for any
// lost revenue, profit, or data, or for direct,
// indirect, special, consequential, incidental, or
// punitive damages, however caused and regardless of
// the theory of liability, arising out of the use of
// or inability to use software, even if Bruce Eckel
// and the publisher have been advised of the
// possibility of such damages. Should the software
// prove defective, you assume the cost of all
// necessary servicing, repair, or correction. If you
// think you've found an error, please email all
// modified files with clearly commented changes to:
// Bruce@EckelObjects.com. (Please use the same
// address for non-code errors found in the book.)
/////////////////////////////////////////////////

// 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 {
    Vector shapeTypes, shapes;
    if(args.length == 0) {
      shapeTypes = new Vector();
      shapes = new Vector();
      // Add handles to the class objects:
      shapeTypes.addElement(Circle.class);
      shapeTypes.addElement(Square.class);
      shapeTypes.addElement(Line.class);
      // Make some shapes:
      for(int i = 0; i < 10; i++)
        shapes.addElement(Shape.randomFactory());
      // Set all the static colors to GREEN:
      for(int i = 0; i < 10; i++)
        ((Shape)shapes.elementAt(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 = (Vector)in.readObject();
      Line.deserializeStaticState(in);
      shapes = (Vector)in.readObject();
    }
    // Display the shapes:
    System.out.println(shapes);
  }
} ///:~