public void update(String id, String r, String t, String q) {
		// TODO Auto-generated method stub
		this.id = id;

		boolean hasChange = false;
		if(r!=null && r.equals(this.Rank)){
			this.lastRank = this.Rank;
			this.Rank = r;
			hasChange = true;
		}

		if(t!=null && t.equals(this.Trend)){
			this.lastTrend = this.Trend;
			this.Trend = t;
			hasChange = true;
		}
		
		if(q!=null && q.equals(this.Quality)){
			this.lastQuality = this.Quality;
			this.Quality = q;
			hasChange = true;
		}
		
		if(hasChange){
			lastChangeTime = System.currentTimeMillis();
		}

	}