<?php
//框架中很常見(jiàn)的adapter類，用來(lái)適配各種數(shù)據(jù)庫(kù)，封裝一些基本數(shù)據(jù)庫(kù)連接操作。
//相當(dāng)于上面代碼中的adapter類
class DbAdapter {
  public function fetchAllFromTable($table) {
    return $arrayOfData;
  }
}
//運(yùn)用prototype pattern的類，注意construct和initialize是分開(kāi)的
//相當(dāng)于上面zend 代碼里面的ResultSet類
class RowGateway {
  public function __construct(DbAdapter $dbAdapter, $tableName) {
    $this->dbAdapter = $dbAdapter;
    $this->tableName = $tableName;
  }
  public function initialize($data) {
    $this->data = $data;
  }
  /**
   * Both methods require access to the database adapter
   * to fulfill their duties
   */
  public function save() {}
  public function delete() {}
  public function refresh() {}
}
//相當(dāng)于上面代碼中的TableGateway類，關(guān)于gateway可以具體去了解一下。
class UserRepository {
  public function __construct(DbAdapter $dbAdapter, RowGateway $rowGatewayPrototype = null) {
    $this->dbAdapter = $dbAdapter;
    $this->rowGatewayPrototype = ($rowGatewayPrototype) ? new RowGateway($this->dbAdapter, 'user')
  }
  public function getUsers() {
    $rows = array();
    foreach ($this->dbAdapter->fetchAllFromTable('user') as $rowData) {
      $rows[] = $row = clone $this->rowGatewayPrototype;
      $row->initialize($rowData);
    }
    return $rows;
  }
}

class ReadWriteRowGateway extends RowGateway {
  public function __construct(DbAdapter $readDbAdapter, DbAdapter $writeDbAdapter, $tableName) {
    $this->readDbAdapter = $readDbAdapter;
    parent::__construct($writeDbAdapter, $tableName);
  }
  public function refresh() {
    // utilize $this->readDbAdapter instead of $this->dbAdapter in RowGateway base implementation
  }
}
// usage:
$userRepository = new UserRepository(
  $dbAdapter,
  new ReadWriteRowGateway($readDbAdapter, $writeDbAdapter, 'user')
);
$users = $userRepository->getUsers();
$user = $users[0]; // instance of ReadWriteRowGateway with a specific row of data from the db