Package javax.microedition.io

[OPTIONAL] Networking support based on the Generic Connection Framework Specification.

See: Description

Interface Summary

Interface	Description
IMCConnection	This interface defines a low-level asynchronous bi-directional stream connection for the Inter-MIDlet Communication protocol (IMC), used for communication between applications.
IMCServerConnection	This interface defines a server connection for the Inter-MIDlet Communication (IMC) protocol that is used for communication between applications.

Class Summary

Class	Description
IMCProtocolPermission	This class represents access rights to connections via the "imc" protocol.
PushRegistry	The PushRegistry maintains a list of inbound connections.
PushRegistryPermission	The PushRegistryPermission class is used to check the static and dynamic registration of push connections and for registration of an alarm.

Package javax.microedition.io Description

[OPTIONAL] Networking support based on the Generic Connection Framework Specification.

Description

The Generic Connection Framework (GCF) is the base for the extended functions:

• IPV4 and IVP6 Support
• Inter-Application-Communications
• Push Applications

Unless otherwise noted, passing a null argument to a constructor or method an any class or interface in this package MUST cause a NullPointerException to be thrown.

IPV4 and IPV6 Support

The attribute MIDlet-Required-IP-Version determines that the implementation MUST use the specified IP version in all the network connections. The implementation MUST NOT allow an application to make connections to ports that have been dedicated to different IP version usage than what the application is requiring. If the implementation cannot provide the application with the required IP version at runtime, an java.io.IOException MUST be thrown.

Inter-Application Communications using IMC

The MIDP Inter-MIDlet Communication protocol defines a low-level, asynchronous, bi-directional stream connection to support direct communication links between applications. IMC is provided by IMCConnection and IMCServerConnection.

Very similar to the socket protocol, the IMC protocol provides for both client and server connection. When an IMC client makes a connection to a server, the IMC server is identified by application UID, and the IMC server name and version. The application UID is the unique identifier of an application, composed of the combination of the application's name, vendor, and version. The application UID is omitted in the connection URL strings when opening an IMC server connection.

The Inter-MIDlet Communication protocol (IMC) MUST be supported by all implementations that include this javax.microedition.io LIBlets enable applications to share software components; however, an application and the LIBlets it depends upon are statically bound at installation into a single isolated runtime execution environment. Further, code belonging to a single LIBlet and bound to multiple application's execution environments cannot easily exchange data at runtime.

With the introduction of Inter-Application communication, an application will be able to access a shareable component running inside another execution environment through thin client APIs, and thus make possible component based programming for applications. The shareable component runs inside another application execution environment and handles requests from other applications.

An example use case for Inter-application communication is a sensor data collector. In this use case, an application controlling a technical facility based on incoming sensor data invokes sensor data collecting applications through an IMC connection in order to receive the collected and processed sensor data needed. These sensor data collecting applications are executed as if they were LIBlets bound to the Controller application, but can be individually installed or deleted and run inside isolated execution environments.

An application starting an IMC server can be launched in the background when the device is powered on, or at client request. Unlike LIBlet code static sharing, an application's IMC server can be independently shut down and unloaded from memory if it is no longer serving client requests. An IMC server can use all of the APIs available to an applications including, when appropriate and available, interactions with the network or user.

Push Applications

The PushRegistry is available to provide an application with a means to register for network connection events, which are delivered to the application if it is running or start the application if it is not running and then deliver the network connection event. The security of PushRegistry is defined by the Auto-Invocation Security Policy.

The risks associated with an application’s use of the network are related the potential for network abuse and to costs to the device owner since network use may result in charges. This specification provides a security framework in which network functions can be protected and allowed only to those applications that are assigned to a certain Client associated with a Security Protection Domain that allows those permissions to be granted.

Since:

IMP 1.0