public class History {

private String[] recorders = {"太史伯","太史仲","太史叔","太史季","南史氏"};
    private int record_num = 0;//被崔杼杀害的史官数量
    private String truth = "崔杼弑其君";

public History(int record_num) {
        this.record_num = record_num;
    }

/**
     * 发生
     */
    public void happen(){
        Log.e("历史事件发生",truth);
    }

/**
     * 记录
     */
    public Memoto record(){
        Log.e(recorders[record_num] + "书曰",truth);
        Memoto memoto = new Memoto(truth);
        return memoto;
    }

/**
     * 史官遇害
     */
    public void killRecorder(){
        truth = "暴病而死";
        Log.e("崔杼杀害"+recorders[record_num] + ",妄图篡改历史",truth);
    }

/**
     * 前赴后继
     */
    public void recordAgain(Memoto memoto){
        this.truth = memoto.getTruth();
        Log.e(recorders[record_num] + "嗣书",truth);
    }

}

public class Memoto {

private String truth;

public Memoto(String truth) {
        this.truth = truth;
    }

public String getTruth() {
        return truth;
    }
}

public class Caretaker {

Memoto memoto;

public void archive(Memoto memoto){
        this.memoto = memoto;
    }

public  Memoto getMemoto(){
        return memoto;
    }

}

History history_0 = new History(0);
history_0.happen();

Caretaker caretaker = new Caretaker();

caretaker.archive(history_0.record());
history_0.killRecorder();

History history_1 = new History(1);
history_1.recordAgain(caretaker.getMemoto());
history_1.killRecorder();

History history_2 = new History(2);
history_2.recordAgain(caretaker.getMemoto());
history_2.killRecorder();

History history_3 = new History(3);
history_3.recordAgain(caretaker.getMemoto());