设计模式
设计模式分为创建型模式、结构型模式和行为型模式。
创建型模式:创建对象。
结构型模式:把复杂结构分解为多个类,分解的是类本身(包括算法和属性)。
行为型模式:把复杂算法分解到多个类,分解的是算法。
示例代码
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| public class MementoPattern { public static void main(String[] args) { Originator originator = new Originator(); originator.setState("state 1"); System.out.println("originator state: " + originator.getState()); Caretaker caretaker = new Caretaker(); caretaker.setMemento(originator.createMemento()); originator.setState("state 2"); System.out.println("originator state: " + originator.getState()); originator.restoreMemento(caretaker.getMemento()); System.out.println("originator state: " + originator.getState()); } }
class Originator { private String state;
public void setState(String state) { this.state = state; }
public String getState() { return state; }
public Memento createMemento() { return new Memento(state); }
public void restoreMemento(Memento memento) { this.state = memento.getState(); } }
class Memento { private String state;
public Memento(String state) { this.state = state; }
public String getState() { return state; } }
class Caretaker { private Memento memento;
public void setMemento(Memento memento) { this.memento = memento; }
public Memento getMemento() { return memento; } }
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