/** GPNode.java
  * J Scott Cameron
  *This interface defines what methods are necessary for
  *a Node in a function tree
  */
import GPPair;

public abstract interface GPNode
{
   
    /*returns the value for the function tree rooted at this node*/
    public abstract Double value() throws NoSuchMethodException;
    
    /*returns the number of children nodes this node has*/
    public abstract int childCount();
    
    /*returns the appropriate child node*/
    public abstract GPNode getChild(int i);
    
    /*sets the appropriate child node*/
    public abstract void setChild(int i,GPNode gpn);
    
    /* returns the size of the tree rooted at this node */
    public abstract int count();
    
    /* returns the node at position i within the tree */
    public abstract GPNode find(int i);
    
    /* returns the number of this node within the tree 
     * it is the root of */
    public abstract int nodeNumber();
    
    /* sets the node with position number*/
    public abstract void setDescendant(int number,GPNode gpn);
    
    /* returns the function rooted at this node */
    public abstract String toString();
    
    /* sets the function at this node */
    public abstract void setFunction(GPPair gpp);
    
    /* returns the type of this node */
    public abstract int getType();
    
    /* returns a new copy of this node */
    public abstract GPNode copy();
    
    
    /* Four types of nodes, used with "getType()" */
    public static final int TERMINAL = 0;
    public static final int VARIABLE = 1;
    public static final int BINARY = 2;
    public static final int UNARY = 3;
}