// Abstract Factory classes are often implemented with Factory Methods, but they
// can also be implemented using Prototype. [GOF, p95]   Abstract Factory might
// store a set of Prototypes from which to clone and return product objects.
// [GOF, p126]  Factory Method: creation through inheritance. Protoype: creation
// through delegation.  Virtual constructor: defer choice of object to create
// until run-time.

public class FactoryFmProto {

static class Expression {
   protected String str;
   public Expression( String s ) { str = s; }
   public Expression cloan()     { return null; }
   public String     toString()  { return str; }
}

static abstract class Factory {
   protected Expression prototype = null;
   public Expression makePhrase() { return prototype.cloan(); }
   public abstract Expression makeCompromise();
   public abstract Expression makeGrade();
}

static class PCFactory extends Factory {
   public PCFactory() { prototype = new PCPhrase(); }
   public Expression makeCompromise() {
      return new Expression( "\"do it your way, any way, or no way\"" ); }
   public Expression makeGrade() {
      return new Expression( "\"you pass, self-esteem intact\"" ); }
}

static class NotPCFactory extends Factory {
   public NotPCFactory() { prototype = new NotPCPhrase(); }
   public Expression makeCompromise() {
      return new Expression( "\"my way, or the highway\"" ); }
   public Expression makeGrade() {
      return new Expression( "\"take test, deal with the results\"" ); }
}

public static void main( String[] args ) {
   Factory factory;
   if (args.length > 0) factory = new PCFactory();
   else                 factory = new NotPCFactory();
   for (int i=0; i < 3; i++) System.out.print( factory.makePhrase() + "  " );
   System.out.println();
   System.out.println( factory.makeCompromise() );
   System.out.println( factory.makeGrade() );
}

// D:\Java\patterns> java FactoryFmProto
// "short"  "lie"  "old"
// "my way, or the highway"
// "take test, deal with the results"
//
// D:\Java\patterns> java FactoryFmProto 1
// "vertically challenged"  "factually inaccurate"  "chronologically gifted"
// "do it your way, any way, or no way"
// "you pass, self-esteem intact"

static class PCPhrase extends Expression {
   static String[] list = { "\"animal companion\"", "\"vertically challenged\"",
                      "\"factually inaccurate\"", "\"chronologically gifted\"" };
   private static int next = 0;
   public PCPhrase()         { super( list[next] );  next = (next+1) % list.length; }
   public Expression cloan() { return new PCPhrase(); }
}

static class NotPCPhrase extends Expression {
   private static String[] list = { "\"pet\"", "\"short\"", "\"lie\"", "\"old\"" };
   private static int next = 0;
   public NotPCPhrase()      { super( list[next] );  next = (next+1) % list.length; }
   public Expression cloan() { return new NotPCPhrase(); }
}}