/* A data structure that holds a timestamp microstep pair.

@Copyright (c) 2008-2009 The Regents of the University of California.
All rights reserved.

Permission is hereby granted, without written agreement and without
license or royalty fees, to use, copy, modify, and distribute this
software and its documentation for any purpose, provided that the
above copyright notice and the following two paragraphs appear in all
copies of this software.

IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
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ENHANCEMENTS, OR MODIFICATIONS.

                                                PT_COPYRIGHT_VERSION_2
                                                COPYRIGHTENDKEY

 */
package ptolemy.domains.ptides.kernel;

import ptolemy.actor.util.Time;

/**
 *  Tag is a pair of timestamp and microstep.
 *
 *  @author Jia Zou
 *  @version $Id$
 *  @since Ptolemy II 7.1
 *  @Pt.ProposedRating Yellow (jiazou)
 *  @Pt.AcceptedRating Red (jiazou)
 *
 */
public class Tag implements Comparable {

    /** Construct a Tag.
     *  @param timestamp The timestamp.
     *  @param microstep The microstep.
     */
    public Tag(Time timestamp, int microstep) {
        this.timestamp = timestamp;
        this.microstep = microstep;
    }

    /** Compare a tag with another.
     *  @param other The object comparing to.
     *  @return The result of the comparison, which is a lexicographical order
     *  with the timestamp as the first element and microstep as the second.
     */
    public int compareTo(Object other) {
        Tag tag2 = (Tag) other;
        if (timestamp.compareTo(tag2.timestamp) == 1) {
            return 1;
        } else if (timestamp.compareTo(tag2.timestamp) == -1) {
            return -1;
        } else {
            if (microstep > tag2.microstep) {
                return 1;
            } else if (microstep < tag2.microstep) {
                return -1;
            } else {
                return 0;
            }
        }
    }

    /** The timestamp. */
    public Time timestamp;

    /** The microstep. */
    public int microstep;
}