sketchmodel.java

Beginning Java 2, SDK 1.4 Edition Exercise Code samples for this book

import java.util.Observable;
import java.util.LinkedList;
import java.util.Iterator;
import java.io.Serializable;
import java.awt.Rectangle;

class SketchModel extends Observable implements Serializable {
  // Get the rectangle enclosing an entire sketch
  Rectangle getModelExtent() {
    Iterator elements = getIterator();
    Rectangle rect = new Rectangle();                // An empty rectangle
    Element element;                                 // Stores an element
    while(elements.hasNext()) {                      // Go through the list
      element = (Element)elements.next();            // Get the next element
      rect.add(element.getBounds());                 // Expand union
    }
    if(rect.width == 0)                              // Make sure width
      rect.width = 1;                                // is non-zero
    if(rect.height == 0)                             // and the height
      rect.height = 1;
    return rect;
  }

  public boolean remove(Element element) {
    boolean removed = elementList.remove(element);
    if(removed) {
      setChanged();
      notifyObservers(element.getBounds());
    }

    return removed;
  }
  
  public void add(Element element) {
    elementList.add(element);
    setChanged();
    notifyObservers(element.getBounds());
  }

  public Iterator getIterator() {
    return elementList.listIterator();  
  }

  protected LinkedList elementList = new LinkedList();
}