DatabaseVersionHeader.java

/*
 * Syncany, www.syncany.org
 * Copyright (C) 2011-2014 Philipp C. Heckel <philipp.heckel@gmail.com> 
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */
package org.syncany.database;

import java.util.Date;

/**
 * The database version header identifies a {@link DatabaseVersion} using 
 * a {@link VectorClock}, a local timestamp and the client's machine name.
 * 
 * <p>The database version header plays a significant role in the 
 * reconciliation process, in particular when trying to find a winning 
 * branch. 
 * 
 * @author Philipp C. Heckel <philipp.heckel@gmail.com>
 */
public class DatabaseVersionHeader {
	private Date date;
    private VectorClock vectorClock;
    private String client;
    
    public DatabaseVersionHeader() {
    	this.date = new Date();
    	this.vectorClock = new VectorClock();
    	this.client = "UnknownMachine";
    }    

    public Date getDate() {
		return date;
	}
	
	public void setDate(Date timestamp) {
		this.date = timestamp;
	}
	
	public VectorClock getVectorClock() {
		return vectorClock;
	}	
	
	public void setVectorClock(VectorClock vectorClock) {
		this.vectorClock = vectorClock;
	}
	
	public String getClient() {
		return client;
	}

	public void setClient(String client) {
		this.client = client;
	}
	
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((date == null) ? 0 : date.hashCode());
		result = prime * result + ((client == null) ? 0 : client.hashCode());
		result = prime * result + ((vectorClock == null) ? 0 : vectorClock.hashCode());
		return result;
	}
	
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		DatabaseVersionHeader other = (DatabaseVersionHeader) obj;
		if (date == null) {
			if (other.date != null)
				return false;
		} else if (!date.equals(other.date))
			return false;
		if (client == null) {
			if (other.client != null)
				return false;
		} else if (!client.equals(other.client))
			return false;
		if (vectorClock == null) {
			if (other.vectorClock != null)
				return false;
		} else if (!vectorClock.equals(other.vectorClock))
			return false;
		return true;
	}

	@Override
	public String toString() {
		StringBuffer sb = new StringBuffer();
				
		sb.append(client);
		sb.append("/");
		sb.append(vectorClock.toString());
		sb.append("/T=");
		sb.append(date.getTime());
		
		return sb.toString();
	}  
}