Validates parameters passed, checks connection permissions and if
everything's fine, creates an instance of
ReservationDescriptor which would allow to reserve the connection.
Parameters: connectionName - same as connection parameterpassed intojavax.microedition.io.PushRegistry.registerConnection(cannot be null) Parameters: filter - filter as passed intojavax.microedition.io.PushRegistry.registerConnection(cannot be null) Parameters: permissionCallback - callback to check permissions (cannot benull, use dummy implementation if there is need to bypasssecurity checks) connection descriptor (always not null) throws: IllegalArgumentException - if the connection string is not valid,or if the filter string is not valid throws: ConnectionNotFoundException - if the runtime system does notsupport push delivery for the requested connection protocol