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yacy_search_server/source/net/yacy/kelondro/order/MicroDate.java

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2.5 KiB

// MicroDate.java
// (C) 2008 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 3.7.2008 on http://yacy.net
//
// This is a part of YaCy, a peer-to-peer based web search engine
//
// $LastChangedDate: 2006-04-02 22:40:07 +0200 (So, 02 Apr 2006) $
// $LastChangedRevision$
// $LastChangedBy$
//
// LICENSE
//
// 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package net.yacy.kelondro.order;
import java.util.Date;
public class MicroDate {
private static final long hour = 3600000L; // milliseconds of a hour
private static final long day = 86400000L; // milliseconds of a day
public static int microDateDays(final Date modified) {
return microDateDays(modified.getTime());
}
public static int microDateDays(final long modified) {
// this calculates a virtual age from a given date
// the purpose is to have an age in days of a given modified date
// from a fixed standpoint in the past
// one day has 60*60*24 seconds = 86400 seconds
// we take mod 64**3 = 262144, this is the mask of the storage
return (int) ((modified / day) % 262144L);
}
public static String microDateHoursStr(final long time) {
return Base64Order.enhancedCoder.encodeLong(microDateHoursInt(time), 3);
}
public static int microDateHoursInt(final long time) {
return (int) ((time / hour) % 262144L);
}
public static int microDateHoursAge(final String mdhs) {
return microDateHoursInt(System.currentTimeMillis()) - (int) Base64Order.enhancedCoder.decodeLong(mdhs);
}
public static long reverseMicroDateDays(final long microDateDays) {
return Math.min(System.currentTimeMillis(), microDateDays * day);
}
public static void main(final String[] args) {
}
}