isProtected()) return false;
        $input = $this->fromString($input);
        $value = is_null($this->local) ? $this->default : $this->local;
        if($value == $input) return false;
        foreach($input as $item) {
            if($this->pattern && !preg_match($this->pattern, $item)) {
                $this->error = true;
                $this->input = $input;
                return false;
            }
        }
        $this->local = $input;
        return true;
    }
    /** @inheritdoc */
    public function html(\admin_plugin_config $plugin, $echo = false) {
        $disable = '';
        if($this->isProtected()) {
            $value = $this->protected;
            $disable = 'disabled="disabled"';
        } else {
            if($echo && $this->error) {
                $value = $this->input;
            } else {
                $value = is_null($this->local) ? $this->default : $this->local;
            }
        }
        $key = htmlspecialchars($this->key);
        $value = htmlspecialchars($this->fromArray($value));
        $label = '';
        $input = '';
        return array($label, $input);
    }
}