001    package biweekly.property;
002    
003    /*
004     Copyright (c) 2013, Michael Angstadt
005     All rights reserved.
006    
007     Redistribution and use in source and binary forms, with or without
008     modification, are permitted provided that the following conditions are met: 
009    
010     1. Redistributions of source code must retain the above copyright notice, this
011     list of conditions and the following disclaimer. 
012     2. Redistributions in binary form must reproduce the above copyright notice,
013     this list of conditions and the following disclaimer in the documentation
014     and/or other materials provided with the distribution. 
015    
016     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
017     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
018     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
019     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
020     ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
021     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
022     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
023     ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
024     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
025     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
026     */
027    
028    /**
029     * Defines a revision number for a component. The organizer of the event, to-do,
030     * etc can increment this number every time he or she makes a significant change
031     * to the component.
032     * @author Michael Angstadt
033     * @see <a href="http://tools.ietf.org/html/rfc5545#page-138">RFC 5545
034     * p.138-9</a>
035     */
036    public class Sequence extends IntegerProperty {
037            /**
038             * Creates a sequence property.
039             * @param sequence the sequence number (e.g. "0" for the initial version,
040             * "1" for the first revision, etc)
041             */
042            public Sequence(Integer sequence) {
043                    super(sequence);
044            }
045    
046            /**
047             * Increments the sequence number.
048             */
049            public void increment() {
050                    if (value == null) {
051                            value = 1;
052                    } else {
053                            value++;
054                    }
055            }
056    }