/*******************************************************************************
 * Breakout Cave Survey Visualizer
 *
 * Copyright (C) 2014 James Edwards
 *
 * jedwards8 at fastmail dot fm
 *
 * 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 org.andork.bind;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public abstract class Binder<T> {
	protected static void bind0(Binder<?> upstream, Binder<?> downstream) {
		if (!upstream.downstream.contains(downstream)) {
			upstream.downstream.add(downstream);
		}
	}

	protected static void unbind0(Binder<?> upstream, Binder<?> downstream) {
		upstream.downstream.remove(downstream);
	}

	private final LinkedList<Binder<?>> downstream = new LinkedList<Binder<?>>();

	private final List<Binder<?>> unmodifiableDownstream = Collections.unmodifiableList(downstream);

	public abstract T get();

	public List<Binder<?>> getDownstream() {
		return unmodifiableDownstream;
	}

	public abstract void set(T newValue);

	public abstract void update(boolean force);

	protected final void updateDownstream(boolean force) {
		for (Binder<?> binder : downstream) {
			binder.update(force);
		}
	}
}