Container

The Container class.

Overview

The container class represents an object which should be (de)serializable through GPDS.

The following figure shows the container class design and related classes:

Figure 1: Container class design

Value

A value is a key-value pair consisting of a string key and a value of one of the following types:
  • bool
  • int
  • double
  • std::string
  • container* (for nesting)

Add a value

Adding a value can be achieved by using the container::add_value() function:

gpds::container c;

double scale = 4.2;
c.add_value( "scale", scale );

Get a value

Getting a value from a deserialized container can be achieved through the container::get_value() function. The value's key is passed as a parameter:

double scale = c.get_value<double>( "scale" );

Get a value with a default value

The container::get_value() function also allows supplying an optional default value which will be returned if no value exists for the specified key:

double scale = c.get_value<double>( "scale", 1.0 );

Get multiple values with the same key

It's possible to store multiple values with the same key in a container. Multiple values can be retrieved from a deserialized container by using the container::get_values() function:

for (const gpds::container* car_container : c.get_values<gpds::container*>( "car" ) ) {
    class car car;
    car.from_container(*car_container);
    cars.push_front(car);
}

Attribute

An attribute is a key-value pair where both the key and the value or of type std::string.

Keys are unique. Calling add_argument() with a key that has previously alredy been added will have no effect. The previously passed value will remain being associated with the specified key.

Add an argument

gpds::container c;
c.add_attribute("id", "72042135");

Get an argument

gpds::container c;
std::cout << "id=" << c.get_attribute("id") << std::endl;