Constructor Prototype Pattern prototype pattern (PHP example), prototypepattern_PHP tutorial

 <span>public</span> <span>function</span><span> getServiceConfig()
    {
        </span><span>return</span> <span>array</span><span>(
            </span>'factories' => <span>array</span><span>(
                </span>'Album\Model\AlbumTable' =>  <span>function</span>(<span>$sm</span><span>) {
                    </span><span>$tableGateway</span> = <span>$sm</span>->get('AlbumTableGateway'<span>);
                    </span><span>$table</span> = <span>new</span> AlbumTable(<span>$tableGateway</span><span>);
                    </span><span>return</span> <span>$table</span><span>;
                }</span>,
                'AlbumTableGateway' => <span>function</span> (<span>$sm</span><span>) {
                    </span><span>$dbAdapter</span> = <span>$sm</span>->get('Zend\Db\Adapter\Adapter'<span>);
                    </span><span>$resultSetPrototype</span> = <span>new</span><span> ResultSet();
                    </span><span>$resultSetPrototype</span>->setArrayObjectPrototype(<span>new</span> Album());<span>//</span><span>这个就是一个不变的原型</span>
                    <span>return</span> <span>new</span> TableGateway('album', <span>$dbAdapter</span>, <span>null</span>, <span>$resultSetPrototype</span>);<span>//</span><span>传入到TableGateWay的构造函数中去</span>
                },<span>
            )</span>,<span>
        );
    }</span>

<a href="http://ralphschindler.com/2012/03/09/php-constructor-best-practices-and-the-prototype-pattern">PHP Constructor Best Practices And The Prototype Pattern</a>

<?<span>php
</span><span>//</span><span>框架中很常见的adapter类，用来适配各种数据库，封装一些基本数据库连接操作。
//相当于上面代码中的adapter类</span>
<span>class</span><span> DbAdapter {
    </span><span>public</span> <span>function</span> fetchAllFromTable(<span>$table</span><span>) {
        </span><span>return</span> <span>$arrayOfData</span><span>;
    }
}

</span><span>//</span><span>运用prototype pattern的类，注意construct和initialize是分开的
//相当于上面zend 代码里面的ResultSet类</span>
<span>class</span><span> RowGateway {

    </span><span>public</span> <span>function</span> __construct(DbAdapter <span>$dbAdapter</span>, <span>$tableName</span><span>) {
        </span><span>$this</span>->dbAdapter = <span>$dbAdapter</span><span>;
        </span><span>$this</span>->tableName = <span>$tableName</span><span>;
    }

    </span><span>public</span> <span>function</span> initialize(<span>$data</span><span>) {
        </span><span>$this</span>->data = <span>$data</span><span>;
    }

    </span><span>/*</span><span>*
     * Both methods require access to the database adapter
     * to fulfill their duties
     </span><span>*/</span>
    <span>public</span> <span>function</span><span> save() {}
    </span><span>public</span> <span>function</span><span> delete() {}
    </span><span>public</span> <span>function</span><span> refresh() {}

}

</span><span>//</span><span>相当于上面代码中的TableGateway类，关于gateway可以具体去了解一下。</span>
<span>class</span><span> UserRepository {

    </span><span>public</span> <span>function</span> __construct(DbAdapter <span>$dbAdapter</span>, RowGateway <span>$rowGatewayPrototype</span> = <span>null</span><span>) {
        </span><span>$this</span>->dbAdapter = <span>$dbAdapter</span><span>;
        </span><span>$this</span>->rowGatewayPrototype = (<span>$rowGatewayPrototype</span>) ? <span>new</span> RowGateway(<span>$this</span>->dbAdapter, 'user'<span>)
    }

    </span><span>public</span> <span>function</span><span> getUsers() {
        </span><span>$rows</span> = <span>array</span><span>();
        </span><span>foreach</span> (<span>$this</span>->dbAdapter->fetchAllFromTable('user') <span>as</span> <span>$rowData</span><span>) {
            </span><span>$rows</span>[] = <span>$row</span> = <span>clone</span> <span>$this</span>-><span>rowGatewayPrototype;
            </span><span>$row</span>->initialize(<span>$rowData</span><span>);
        }
        </span><span>return</span> <span>$rows</span><span>;
    }

}</span>

<span>class</span> ReadWriteRowGateway <span>extends</span><span> RowGateway {
    </span><span>public</span> <span>function</span> __construct(DbAdapter <span>$readDbAdapter</span>, DbAdapter <span>$writeDbAdapter</span>, <span>$tableName</span><span>) {
        </span><span>$this</span>->readDbAdapter = <span>$readDbAdapter</span><span>;
        parent</span>::__construct(<span>$writeDbAdapter</span>, <span>$tableName</span><span>);
    }

    </span><span>public</span> <span>function</span><span> refresh() {
        </span><span>//</span><span> utilize $this->readDbAdapter instead of $this->dbAdapter in RowGateway base implementation</span>
<span>    }
}


</span><span>//</span><span> usage:</span>
<span>$userRepository</span> = <span>new</span><span> UserRepository(
    </span><span>$dbAdapter</span>,
    <span>new</span> ReadWriteRowGateway(<span>$readDbAdapter</span>, <span>$writeDbAdapter</span>, 'user'<span>)
);
</span><span>$users</span> = <span>$userRepository</span>-><span>getUsers();
</span><span>$user</span> = <span>$users</span>[0]; <span>//</span><span> instance of ReadWriteRowGateway with a specific row of data from the db</span>