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OSGi™ Service Platform Release 2 |
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A Driver service object must be registered by each Driver bundle
wishing to attach to Device services provided by other drivers.
For each newly discovered Device
object, the device manager
enters a bidding phase. The Driver object whose
match(org.osgi.framework.ServiceReference)
method bids the highest for a particular
Device object will be instructed by the device manager to attach to
the Device object.
Device
,
DriverLocator
Method Summary | |
java.lang.String |
attach(ServiceReference reference)
Attaches this Driver service to the Device service represented by the given ServiceReference object. |
int |
match(ServiceReference reference)
Checks whether this Driver service can be attached to the Device service represented by the given ServiceReference and returns a value
indicating how well this driver can support the given Device service,
or Device.Device.MATCH_NONE if it cannot support the given
Device service at all. |
Method Detail |
public int match(ServiceReference reference) throws java.lang.Exception
ServiceReference
and returns a value
indicating how well this driver can support the given Device service,
or Device.Device.MATCH_NONE
if it cannot support the given
Device service at all.
The return value must be one of the possible match values defined in the device category definition for the given Device service, or Device.MATCH_NONE if the category of the Device service is not recognized.
In order to make its decision, this Driver service may examine the properties associated with the given Device service, or may get the referenced service object (representing the actual physical device) to talk to it, as long as it ungets the service and returns the physical device to a normal state before this method returns.
A Driver service must always return the same match code whenever it is presented with the same Device service.
The match function is called by the device manager during the matching process.
reference
- the ServiceReference object of the device to match
java.lang.Exception
- if this Driver service cannot
examine the Device servicepublic java.lang.String attach(ServiceReference reference) throws java.lang.Exception
A return value of null indicates that this Driver service has successfully attached to the given Device service. If this Driver service is unable to attach to the given Device service, but knows of a more suitable Driver service, it must return the DRIVER_ID of that Driver service. This allows for the implementation of referring drivers whose only purpose is to refer to other drivers capable of handling a given Device service.
After having attached to the Device service, this driver may register the underlying device as a new service exposing driver-specific functionality.
This method is called by the device manager.
reference
- the ServiceReference object of the device to attach to
java.lang.Exception
- if the driver cannot attach to the
given device and does not know of a more suitable driver
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OSGi™ Service Platform Release 2 |
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PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |