Exporting a Service

A service is typically exported and registered with the OSGi framework using one of the following methods:

void addExportedService(String, Object, Dictionary)
void addExportedServices(String[], Object, Dictionary)

The methods differ in that the first method is used to register the service under a single service name, whereas the second method allows the service to be registered under multiple service names. In both cases the second parameter is the service object to be registered, and the third parameter is a Dictionary of properties to be registered with the service. If no properties are to be registered, simply pass null.

The method addExportedService(String, Object, Dictionary) is most commonly used, for example:

  protected void activate() {
    Object service = new HotdogVendor();
    Dictionary properties = new Hashtable(11);
    properties.put("spicy", new Integer(7));  //$NON-NLS-1$
    addExportedService(VendorService.SERVICE_NAME, service, properties);
  }

To register a single service under multiple service names, use the method addExportedServices(String[], Object, Dictionary), for example:

  protected void activate() {
    Object service = new Shimmer();
    
    String[] names = new String[] {
      DessertToppingService.SERVICE_NAME,
      FloorWaxService.SERVICE_NAME
    };
    
    Dictionary properties = new Hashtable(11);    
    properties.put("viscosity", "medium");  //$NON-NLS-1$  //$NON-NLS-2$
    addExportedServices(names, service, properties);
  }

When registering multiple services in this way, the same set of properties are used to register the service under each of the service names. This means that changing the properties later will affect the service for each of its registered service names. To register a unique set of properties for each service name, register the service individually for each service name, for example:

  protected void activate() {
    Object service = new Shimmer();
    
    // DessertToppingService
    Dictionary dessertToppingProperties = new Hashtable(11);    
    dessertToppingProperties.put("flavor", "banana");  //$NON-NLS-1$  //$NON-NLS-2$
    addExportedService(DessertToppingService.SERVICE_NAME, service, dessertToppingProperties);

	// FloorWaxService
    Dictionary floorWaxProperties = new Hashtable(11);    
    floorWaxProperties.put("viscosity", "medium");  //$NON-NLS-1$  //$NON-NLS-2$
    addExportedService(FloorWaxService.SERVICE_NAME, service, floorWaxProperties);
  }