Apache Geode Native C++ CHANGELOG

PdxSerializable Example

The native client release contains an example showing how a client application can register for serialization of custom objects using the C++ PdxSerializable abstract class.

The example is located in examples/cpp/pdxserializable.

The example defines the serializable class, Orders, including its serialization and deserialization methods and its factory method. Once these pieces are in place, execution is simple: the main routine of the example registers the serializable class then performs some put and get operations.

Execution

The example performs a sequence of operations, displaying simple log entries as they run.

To run the example, follow the instructions in the README.md file in the example directory.
Review the source code in the example directory to see exactly how it operates.
Begin by running a script that sets up the server-side environment by invoking gfsh commands to create a region, a locator, and a server.
Run the example client application, which performs the following steps:
- Connects to the server
- Registers the PdxSerializable class
- Creates orders
- Stores orders
- Retrieves orders

C++ Example

This section contains code snippets showing highlights of the C++ PdxSerialiable example. They are not intended for cut-and-paste execution. For the complete source, see the example source directory.

The C++ example defines a PdxSerializable class called Order that inherits from the PdxSerializable abstract class. An Order object contains three fields:

an integer order_id
a string name
a short-int quantity

From Order.hpp:

class Order : public PdxSerializable {
 public:
 ...

 private:
  int32_t order_id_;
  std::string name_;
  int16_t quantity_;
};

Using the PdxSerializable read and write methods, the Order class defines fromData() and toData() methods that perform the deserialization and serialization operations, respectively, and the createDeserializable() factory method:

From Order.cpp:

void Order::fromData(PdxReader& pdxReader) {
  order_id_ = pdxReader.readInt(ORDER_ID_KEY_);
  name_ = pdxReader.readString(NAME_KEY_);
  quantity_ = pdxReader.readShort(QUANTITY_KEY_);
}

void Order::toData(PdxWriter& pdxWriter) const {
  pdxWriter.writeInt(ORDER_ID_KEY_, order_id_);
  pdxWriter.markIdentityField(ORDER_ID_KEY_);

  pdxWriter.writeString(NAME_KEY_, name_);
  pdxWriter.markIdentityField(NAME_KEY_);

  pdxWriter.writeShort(QUANTITY_KEY_, quantity_);
  pdxWriter.markIdentityField(QUANTITY_KEY_);
}

...

std::shared_ptr<PdxSerializable> Order::createDeserializable() {
  return std::make_shared<Order>();
}

The C++ example mainline creates a cache, then uses it to create a connection pool and a region object (of class Region).

  auto cache = CacheFactory()
      .set("log-level", "none")
      .create();

  cache.getPoolManager()
      .createFactory()
      .addLocator("localhost", 10334)
      .create("pool");

  auto regionFactory = cache.createRegionFactory(RegionShortcut::PROXY);
  auto region = regionFactory.setPoolName("pool").create("custom_orders");

The client registers the PdxSerializable class that was created in Orders.cpp:

  cache.getTypeRegistry().registerPdxType(Order::createDeserializable);

The client then instantiates and stores two Order objects:

  auto order1 = std::make_shared<Order>(1, "product x", 23);
  auto order2 = std::make_shared<Order>(2, "product y", 37);

  region->put("Customer1", order1);
  region->put("Customer2", order2);

Next, the application retrieves the stored values, in one case extracting the fields defined in the serialization code:

  if (auto order1retrieved =
          std::dynamic_pointer_cast<Order>(region->get("Customer1"))) {
    std::cout << "OrderID: " << order1retrieved->getOrderId() << std::endl;
    std::cout << "Product Name: " << order1retrieved->getName() << std::endl;
    std::cout << "Quantity: " << order1retrieved->getQuantity() << std::endl;
  } else {
    std::cout << "Order 1 not found." << std::endl;
  }

The application retrieves the second object and displays it without extracting the separate fields:

  if (region->existsValue("rtimmons")) {
    std::cout << "rtimmons's info not deleted" << std::endl;
  } else {
    std::cout << "rtimmons's info successfully deleted" << std::endl;
  }

Finally, the application closes the cache:

  cache.close();