org.osgi.framework
Interface ServiceReference

public interface ServiceReference

A reference to a service.

The Framework returns ServiceReference objects from the BundleContext.getServiceReference and BundleContext.getServiceReferences methods.

A ServiceReference may be shared between bundles and can be used to examine the properties of the service and to get the service object.

Every service registered in the Framework has a unique ServiceRegistration object and may have multiple, distinct ServiceReference objects referring to it. ServiceReference objects associated with a ServiceRegistration object have the same hashCode and are considered equal (more specifically, their equals() method will return true when compared).

If the same service object is registered multiple times, ServiceReference objects associated with different ServiceRegistration objects are not equal.

Version:

$Revision: 1.1 $

Author:

Open Services Gateway Initiative

See Also:

BundleContext.getServiceReference(java.lang.String), BundleContext.getServiceReferences(java.lang.String, java.lang.String), BundleContext.getService(org.osgi.framework.ServiceReference)

Method Summary

Bundle	getBundle() Returns the bundle that registered the service referenced by this ServiceReference object.
java.lang.Object	getProperty(java.lang.String key) Returns the property value to which the specified property key is mapped in the properties Dictionary object of the service referenced by this ServiceReference object.
java.lang.String[]	getPropertyKeys() Returns an array of the keys in the properties Dictionary object of the service referenced by this ServiceReference object.
Bundle[]	getUsingBundles() Returns the bundles that are using the service referenced by this ServiceReference object.

Method Detail

getProperty

java.lang.Object getProperty(java.lang.String key)

Returns the property value to which the specified property key is mapped in the properties Dictionary object of the service referenced by this ServiceReference object.

Property keys are case-insensitive.

This method must continue to return property values after the service has been unregistered. This is so references to unregistered services (for example, ServiceReference objects stored in the log) can still be interrogated.

Parameters:

key - The property key.

Returns:

The property value to which the key is mapped; null if there is no property named after the key.

getPropertyKeys

java.lang.String[] getPropertyKeys()

Returns an array of the keys in the properties Dictionary object of the service referenced by this ServiceReference object.

This method will continue to return the keys after the service has been unregistered. This is so references to unregistered services (for example, ServiceReference objects stored in the log) can still be interrogated.

This method is case-preserving; this means that every key in the returned array must have the same case as the corresponding key in the properties Dictionary that was passed to the BundleContext.registerService(java.lang.String[], java.lang.Object, java.util.Dictionary) or ServiceRegistration.setProperties(java.util.Dictionary) methods.

Returns:

An array of property keys.

getBundle

Bundle getBundle()

Returns the bundle that registered the service referenced by this ServiceReference object.

This method will always return null when the service has been unregistered. This can be used to determine if the service has been unregistered.

Returns:

The bundle that registered the service referenced by this ServiceReference object; null if that service has already been unregistered.

See Also:

BundleContext.registerService(java.lang.String[], java.lang.Object, java.util.Dictionary)

getUsingBundles

Bundle[] getUsingBundles()

Returns the bundles that are using the service referenced by this ServiceReference object. Specifically, this method returns the bundles whose usage count for that service is greater than zero.

Returns:

An array of bundles whose usage count for the service referenced by this ServiceReference object is greater than zero; null if no bundles are currently using that service.

Since:

1.1