The examples in the subsequent sections illustrate the following aspects of PHP for SCA:
How PHP annotations are used to define PHP classes as SCA components, and how annotations are used to define the services.
How an SCA component can be exposed as a Web service
How an SCA component can consume a Web service, whether provided by another SCA component or by some other service which knows nothing of SCA
How an SCA component can call another SCA component locally (within the same process and on the same call stack)
How a client script which is not an SCA component can use the getService call to obtain a proxy for an SCA component.
How data structures such as Addresses, or Puchase Orders, are represented as Service Data Objects, and handled.
How SCA components are deployed, and in particular how and when WSDL is generated for a service.
How parameters are always passed by value (and not by reference) between components, even when the calls are local. This ensures that the semantics of a call do not change depending on the location of a component.
How positional parameters to a service are supported, even when the underlying WSDL is document literal wrapped, and naturally supports only named parameters.
How business and runtime exceptions are handled.
A service component is implemented by a class. To identify it as a service component, it contains an @service annotation. The SCA runtime will use the file name of the script to determine the component name, by convention. The class and script file must therefore share the same name.
PHP SCA components always expose a service, and there is no way for a component to be invoked other than to be called as a result of a Web service request, or called directly from another component or from a script. For this reason a valid PHP SCA component will always contain an @service annotation and at least one public method.
Each SCA Component requires that the SCA.php script is included. As well as containing the definition of the SCA class, this script contains executable PHP code that will run whenever the script is called, and which will be responsible for making the component behave as needed.
It is very important that if your file contains other includes, they come before the include for SCA.php. If there are includes after the include for SCA.php, they will not have been processed when the SCA runtime runs your class.
The example below illustrates this overall structure
Example #1 The structure of an SCA for PHP component
<?php
// any includes
include "SCA/SCA.php";
/**
* @service
*/
class ConvertedStockQuote {
// instance variables, business logic, including at least one public method
}
?>