package org.apidesign.stateful.api;

 /** API for notifying progress.

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 // BEGIN: progress.api

 public abstract class ProgressStateful {

     public static ProgressStateful create(String name) {

         return createImpl(name);

     }

     public abstract void start(int totalAmount);

     public abstract void progress(int howMuch);

     public abstract void finish();

     // FINISH: progress.api

     ProgressStateful() {

     }

     private static ProgressStateful createImpl(String name) {

         return new Impl(name);

     }

     private static final class Impl extends ProgressStateful {

         private final String name;

         private int total = -1;

         private int current;

         public Impl(String name) {

             this.name = name;

         }

         @Override

         public void start(int totalAmount) {

             total = totalAmount;

         }

         @Override

         public void progress(int howMuch) {

             if (total == -1) {

                 throw new IllegalStateException("Call start first!");

             }

             current = howMuch;

         }

         @Override

         public void finish() {

             total = -1;

             current = 0;

         }

     }

 }