php状态模式(state pattern)

...

<?php
/*
The state pattern encapsulates the varying behavior for the same object based on its
internal state, making an object appear as if it has changed its class.
*/

interface  Statelike {
    public function writeName(StateContext $context, $name);
}

class StateLowerCase implements Statelike {
    public function writeName(StateContext $context, $name) {
        echo strtolower($name);
        $context->setState(new StateMultileUpperCase());
    }
}

class StateMultileUpperCase implements Statelike {
    private $count = 0;

    public function writeName(StateContext $context, $name) {
        $this->count++;
        echo strtoupper($name);

        if ($this->count > 1) {
            $context->setState(new StateLowerCase());
        }
    }
}

class StateContext {
    private $state;

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

    public function writeName($name) {
        $this->state->writeName($this, $name);
    }
}

$stateContext = new StateContext();
$stateContext->setState(new StateLowerCase());
$stateContext->writeName('Monday<br/>');
$stateContext->writeName('TuesDay<br/>');
$stateContext->writeName('Wednesday<br/>');
$stateContext->writeName('Thursday<br/>');
$stateContext->writeName('Friday<br/>');
$stateContext->writeName('Saturday<br/>');
$stateContext->writeName('Sunday<br/>');

?>