PHPオブジェクトインターフェース

interface ITemplate
{
    public function setVariable($name,$var);
    public function getHtml($template);
}
//实现接口
//下面的写法是正确的
class Template implements ITemplate
{
    private $vars = array();
    public function setVariable($name,$var)
    {
        $this->vars[$name] = $var;
    }
    public function getHtml($template)
    {
        foreach($this->vars as $name => $value){
            $template = str_replace('{'.$name.'}',$value,$template);
        }
        return $template;
    }
}
//下面的写法是错误的，会报错，因为没有实现getHtml()
class BadTemplate implements ITemplate
{
    private $vars = array();
    public function setVariable($name,$var)
    {
        $this->vars[$name] = $var;
    }
}

interface a
{
    public function foo();
}
interface b extends a
{
    public function baz(Baz $baz);
}
//正确写法
class c implements b
{
    public function foo(){}
    public function baz(Baz $baz){}
}
//错误写法
class d implements b
{
    public function foo(){}
    public function baz(Foo $foo){}
}

interface a
{
    public function foo();
}
interface b
{
    public function bar();
}
interface c extends a,b
{
    public function baz();
}
class d implements c
{
    public function foo(){}
    public function bar(){}
    public function baz(){}
}

interface a
{
    const b = 1;
}
//输出接口常量
echo a::b;
//错误写法
class b implements a
{
    const b = 1;
}