Android Plugin-Basic Principles of OSGI service in apkplug-08

 

Similarities and differences between OSGI and android Service

The OSGI Service and android Service are similar in terms of Service and Client.

Android Service interface -- service. AIDL

OSGI interface -- java interface

Therefore, the android inter-process communication Service can only transmit serialized data, while the OSGI Service can transmit any java object.

 

Comparison between OSGI and android Service Registration/query methods

1. Service Registration

Android Service

1	Intent intent=new Intent(Context,Service.class);

2	Context.startService(intent);

OSGI Service

 

1	BundleContext context; // Plugin Context

2	ServiceRegistration m_reg = context.registerService(

3	sayHelloImp.class.getName(),// The service name is generally the Interface Class Name

4	my, // Service implementation class

5

null);

2. Service Query

Android Service

1	Intent intent=new Intent(Context,Service.class);

2	Context.bindService(intent, new ServiceConnection())

3

...

OSGI Service

 

01	// Use the plug-in context BundleContext to query the service

02	ServiceReference ref = context.getServiceReference(Service.class.getName());

03	if (ref != null ) {

04	// Find the service

05	Service service = (Service) context.getService(ref);

06	if (service != null ) {

07	// Call the service interface

08	service.sayHello(imp);

09

}

10	// Deregister the service

11	context.ungetService(ref);

12

}

 

Iii. OSGI service features

The OSGI service is a transient plug-in that may be disabled or uninstalled at any time. Therefore, we recommend that you first check whether the service still exists when using the service.

4. OSGI service considerations

When using the OSGI service, pay attention to the consistency of the java class of the service interface. The service provider and the consumer should use the same java interface (the class loader is the same). Otherwise, the type forced conversion exception may occur during service query. Generally, we provide java interfaces as service providers.