// file:    Seed.java
// author:  Robert Keller
// purpose: a Seed is an object which can grow into something else by
//          calling a method

package polya;

import java.io.*;
import java.lang.*;
	
/**
  * A Seed can grow into any other Object.
 **/

class Seed
  {
  Object value;


  /**
    * Create a Seed.
    *@arg growable the Growable from which the final value is produced.
   **/

  Seed(Growable growable)
    {
    this.value = growable;
    }

  /**
    * grow the seed, iterating as long as the result is a Growable,
    * returning the final value.
   **/

  Object grow()
    {
    while( value instanceof Growable )
      {
      value = ((Growable)value).grow();
      }
    return value;
    }
  }