CommandPatternExample

gistfile1.txt

// A Command Pattern example 
// Oringinal example from https://dzone.com/articles/design-patterns-command and I modify it using java8

public class Client {
    public static void main(String[] args) {
        // Receiver
        Light light = new Light();
        // Invoker
        RemoteControl remoteControl = new RemoteControl();

        remoteControl.setCommand(light::switchOn);
        remoteControl.pressButton();

        System.out.println(light.isOn());

        remoteControl.setCommand(light::switchOff);
        remoteControl.pressButton();

        System.out.println(light.isOn());
    }


}

public interface Command {
    void execute();
}

public class Light {
    private boolean on;

    public boolean isOn() {
        return on;
    }

    public void switchOn(){
        System.out.println("switchOn");
        on = true;
    }
    public void switchOff(){
        System.out.println("switchOff");
        on = false;
    }
}

public class RemoteControl {
    private Command command;

    public void setCommand(Command command) {
        this.command = command;
    }

    void pressButton(){
        command.execute();
    }


}