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;

        }

    }

}