DelayedChangeManager.java

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/*
 * Gridarta MMORPG map editor for Crossfire, Daimonin and similar games.
 * Copyright (C) 2000-2015 The Gridarta Developers.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

package net.sf.gridarta.utils;

import java.util.Timer;
import java.util.TimerTask;
import org.jetbrains.annotations.NotNull;

public class DelayedChangeManager {

    private final int initialDelay;

    private final int notificationDelay;

    @NotNull
    private final DelayedChangeListener delayedChangeListener;

    @NotNull
    private final Timer timer = new Timer();

    private class TimeoutTimerTask extends TimerTask {

        @Override
        public void run() {
            state = state.timeout();
        }

    }

    private interface State {

        @NotNull
        State change();

        @NotNull
        State finish();

        @NotNull
        State timeout();

    }

    @NotNull
    private final State idle = new State() {

        @NotNull
        @Override
        public State change() {
            timer.schedule(new TimeoutTimerTask(), initialDelay);
            return pending;
        }

        @NotNull
        @Override
        public State finish() {
            return idle;
        }

        @NotNull
        @Override
        public State timeout() {
            assert false;
            return idle;
        }

    };

    @NotNull
    private final State pending = new State() {

        @NotNull
        @Override
        public State change() {
            return pending;
        }

        @NotNull
        @Override
        public State finish() {
            delayedChangeListener.change();
            return wait;
        }

        @NotNull
        @Override
        public State timeout() {
            timer.schedule(new TimeoutTimerTask(), notificationDelay);
            delayedChangeListener.change();
            return wait;
        }

    };

    @NotNull
    private final State wait = new State() {

        @NotNull
        @Override
        public State change() {
            return pending;
        }

        @NotNull
        @Override
        public State finish() {
            return wait;
        }

        @NotNull
        @Override
        public State timeout() {
            return idle;

        }

    };

    @NotNull
    private State state = idle;

    public DelayedChangeManager(final int initialDelay, final int notificationDelay, @NotNull final DelayedChangeListener delayedChangeListener) {
        this.initialDelay = initialDelay;
        this.notificationDelay = notificationDelay;
        this.delayedChangeListener = delayedChangeListener;
    }

    public void change() {
        state = state.change();
    }

    public void finish() {
        state = state.finish();
    }

}