java学习笔记-设计模式21(状态模式)

public class State {  
      
    private String value;  
      
    public String getValue() {  
        return value;  
    }  
  
    public void setValue(String value) {  
        this.value = value;  
    }  
  
    public void method1(){  
        System.out.println("execute the first opt!");  
    }  
      
    public void method2(){  
        System.out.println("execute the second opt!");  
    }  
}  

public class Context {  
  
    private State state;  
  
    public Context(State state) {  
        this.state = state;  
    }  
  
    public State getState() {  
        return state;  
    }  
  
    public void setState(State state) {  
        this.state = state;  
    }  
  
    public void method() {  
        if (state.getValue().equals("state1")) {  
            state.method1();  
        } else if (state.getValue().equals("state2")) {  
            state.method2();  
        }  
    }  
} 

public class Test {  
  
    public static void main(String[] args) {  
          
        State state = new State();  
        Context context = new Context(state);  
          
        //设置第一种状态  
        state.setValue("state1");  
        context.method();  
          
        //设置第二种状态  
        state.setValue("state2");  
        context.method();  
    }  
}