FiletimeUtil.java

package javastory.tools;

import java.util.Date;
import java.util.TimeZone;

/**
 * Provides a suite of tools for manipulating Korean Timestamps.
 * 
 * @author Frz
 * @since Revision 746
 * @version 1.0
 */
public class FiletimeUtil {

	public final static long ITEM_EXPIRATION = getItemExpiration();
	public final static long ITEM_EXPIRATION_2 = getItemExpiration2();

	private static long getItemExpiration() {
		return 150842304000000000L;
	}

	private static long getItemExpiration2() {
		return 94354848000000000L;
	}

	// 100-ns intervals from 1/1/1601 -> 1/1/1970
	private final static long FILETIME_UNIXTIME_OFFSET = 116444736000000000L;

	/**
	 * Converts a Unix Timestamp into File Time
	 * 
	 * @param unixtime
	 *            the timestamp in UNIX time
	 * @return A 64-bit the file time timestamp
	 */
	public static long getFiletime(final long unixtime) {
		return unixtime * 10000 + FILETIME_UNIXTIME_OFFSET;
	}

	public static boolean isDST() {
		return TimeZone.getDefault().inDaylightTime(new Date());
	}

	public static long getFileTimestamp(long unixtime, final boolean roundToMinutes) {
		if (isDST()) {
			unixtime -= 3600000L;
		}
		long time;
		if (roundToMinutes) {
			time = unixtime / 1000 / 60 * 600000000;
		} else {
			time = unixtime * 10000;
		}
		return time + FILETIME_UNIXTIME_OFFSET;
	}
}