StringUtil.java

/**
 * File: $HeadURL: https://hdt-java.googlecode.com/svn/trunk/hdt-java/src/org/rdfhdt/hdt/util/StringUtil.java $
 * Revision: $Rev: 191 $
 * Last modified: $Date: 2013-03-03 11:41:43 +0000 (dom, 03 mar 2013) $
 * Last modified by: $Author: mario.arias $
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Contacting the authors:
 *   Mario Arias:               mario.arias@deri.org
 *   Javier D. Fernandez:       jfergar@infor.uva.es
 *   Miguel A. Martinez-Prieto: migumar2@infor.uva.es
 *   Alejandro Andres:          fuzzy.alej@gmail.com
 */

package org.rdfhdt.hdt.util;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;

/**
 * @author mck
 *
 */
public class StringUtil {
	
	private StringUtil() {}
	
	public static String getPercent(long v1, long max) {
		if(max==0) {
			return "%";
		}
        return String.format("%.2f %%", (100.0*v1)/max);
	}
	
	public static String formatDate(Date date) {
		DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm'Z'");
		dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
		return dateFormat.format(date);
	}
	
	public static String toHuman(long amount) {
		return humanReadableByteCount(amount, true);
	}
	
	public static String humanReadableByteCount(long bytes, boolean si) {
	    int unit = si ? 1000 : 1024;
	    if (bytes < unit) return Long.toString(bytes);
	    int exp = (int) (Math.log(bytes) / Math.log(unit));
	    char pre = "KMGTPE".charAt(exp-1);
	    return String.format("%.1f%c", bytes / Math.pow(unit, exp), pre);
	}
}