package state_pattern;
public abstract class State {
public abstract void Handle(Context context);
}
package state_pattern;
public class ConcreteStateA extends State{
@Override
public void Handle(Context context) {//It implements the logic between related state.
context.setState(new ConcreteStateB());//The current state decide the next state.
}
}
package state_pattern;
public class ConcreteStateB extends State{
@Override
public void Handle(Context context) {
context.setState(new ConcreteStateA());
}
}
package state_pattern;
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;
System.out.println("The current state is " + this.state.getClass().getName());
}
public void request() {
state.Handle(this);//The current class object as the parameter communicate
//with state.The dynamic binding instead of "switch-case".
}
}
package state_pattern;
public class Main {
public static void main(String args[]) {
Context c = new Context(new ConcreteStateA());
c.request();
c.request();
c.request();
c.request();
}
}
/*
* The current object's behavior is related to its state during the runtime.
*/
This is a general introduction to the 23 design patterns：
https://blog.csdn.net/GZHarryAnonymous/article/details/81567214