PeekerUtils.java

/* ========================================================================
 * PlantUML : a free UML diagram generator
 * ========================================================================
 *
 * (C) Copyright 2009-2020, Arnaud Roques
 *
 * Project Info:  https://plantuml.com
 * 
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 * This file is part of PlantUML.
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 * PlantUML 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 3 of the License, or
 * (at your option) any later version.
 *
 * PlantUML 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 library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
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 *
 * Original Author:  Arnaud Roques
 *
 *
 */
package net.sourceforge.plantuml.utils;

import java.util.List;

public abstract class PeekerUtils {
	// ::remove file when __HAXE__

	private PeekerUtils() {

	}

	public static <O> Peeker<O> peeker(final List<O> list) {
		return new Peeker<O>() {

			private int pos = 0;

			@Override
			public O peek(int ahead) {
				final int tmp = pos + ahead;
				if (tmp < list.size())
					return list.get(tmp);
				return null;
			}

			@Override
			public void jump() {
				pos++;
			}

			@Override
			public String toString() {
				if (peek(0) == null)
					return super.toString();
				return peek(0).toString();
			}
		};
	}
}