设计模式——状态模式

说明

示例

下面看下状态模式的代码实现

class State{
    private string $value;

    public function getValue(): string{
        return $this->value;
    }

    public function setValue(string $value){
        $this->value = $value;
    }

    public function method1(){
        echo "execute the first opt!" . PHP_EOL;
    }

    public function method2(){
        echo "execute the second opt!" . PHP_EOL;
    }
}

class Context{
    private State $state;

    public function __construct(State $state){
        $this->state = $state;
    }

    public function getState(): State{
        return $this->state;
    }

    public function setState(State $state){
        $this->state = $state;
    }

    public function method(){
        if ($this->state->getValue() == 'state1'){
            $this->state->method1();;
        }else if($this->state->getValue() == 'state2'){
            $this->state->method2();
        }
    }
}


// 调用
$state = new State();
$context = new Context($state);

$state->setValue('state1');
$context->method();

$state->setValue('state2');
$context->method();
/**
 * output:
 * execute the first opt!
 * execute the second opt!
 * 
 */

总结