public class SoundBranch extends CollectableNode {
  /*
   * A list of children to draw
   */
  public CollectableNode children;

  /*
   * Construct a branch with children and
   * next as null
   **/
  public SoundBranch(){
    super(); // Call superclass constructor
    children = null;
  }
  
  /**
   * Method to return a string with informaiton 
   * about this branch
   */
  public String toString() 
  {
    String childString = "No children", nextString="No next";
    if (children != null)
    {childString = children.toString();}
    if (next != null)
    {nextString = next.toString();}
    
    return "SoundBranch (with child: "+childString+" and next: "+
      nextString+")";
  }

  /**
   * Method to add nodes to children
   **/
  public void addChild(CollectableNode child){
    if (children != null)
    {children.add(child);}
      else
      {children = child;}
  }
  
  /**
   * Collect all the sound from our children,
   * then collect from next.
   * @param pen Turtle to draw with
   **/
  public Sound collect(){
    
    Sound childSound;
    
    if (children != null)
    {childSound = children.collect();}
    else
    {childSound = new Sound(1);}
    
    // Collect from my next
    if (this.getNext() != null)
    {childSound=childSound.append(this.getNext().collect());}
    
    return childSound;
  }
  
    /**
   * Collect all the sound from our children,
   * then collect from next.
   * If there's processing, do to Next, not to Children
   * @param pen Turtle to draw with
   **/
  public Sound collectAfter(){
    
    Sound childSound;
    
    if (children != null)
    {childSound = children.collectAfter();}
    else
    {childSound = new Sound(1);}
    
    // Collect from my next
    if (this.getNext() != null)
    {childSound=childSound.append(this.getNext().collectAfter());}
    
    return childSound;
  }

}