org.apache.sling.api.adapter

Interface AdapterFactory

public interface AdapterFactory

The AdapterFactory interface defines the API for helpers which may be provided to enhance the adaptability of adaptable objects.

Implementations of this interface are registered as OSGi services and are used by the AdapterManager to adapt objects on demand. The AdapterFactory services are not really intended to be used by clients directly.

The AdapterManager implementations ensures that the getAdapter(Object, Class) method is only called for the combination of adaptable and adapter type which is allowed as per the service registration properties ADAPTABLE_CLASSES and ADAPTER_CLASSES.

If multiple implementations for the same combination of adapter and adaptable are registered, the implementation with the lowest service ranking wins (or with the highest service id, if the ranking is the same).

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	ADAPTABLE_CLASSES The service registration property listing the fully qualified names of classes which can be adapted by this adapter factory (value is "adaptables").
static java.lang.String	ADAPTER_CLASSES The service registration property listing the fully qualified names of classes to which this factory can adapt adaptables (value is "adapters").
static java.lang.String	SERVICE_NAME The service name to use when registering implementations of this interface as services.

Method Summary

Modifier and Type	Method and Description
<AdapterType> AdapterType	getAdapter(java.lang.Object adaptable, java.lang.Class<AdapterType> type) Adapt the given object to the adaptable type.

Field Detail

SERVICE_NAME

static final java.lang.String SERVICE_NAME

The service name to use when registering implementations of this interface as services.

See Also:

Constant Field Values

ADAPTABLE_CLASSES

static final java.lang.String ADAPTABLE_CLASSES

The service registration property listing the fully qualified names of classes which can be adapted by this adapter factory (value is "adaptables"). The "adaptable" parameters of the getAdapter(Object, Class) method must be an instance of one of these classes for this factory to be able to adapt the object.

See Also:

Constant Field Values

ADAPTER_CLASSES

static final java.lang.String ADAPTER_CLASSES

The service registration property listing the fully qualified names of classes to which this factory can adapt adaptables (value is "adapters").

See Also:

Constant Field Values

Method Detail

getAdapter

<AdapterType> AdapterType getAdapter(java.lang.Object adaptable,
                                     java.lang.Class<AdapterType> type)

Adapt the given object to the adaptable type. The adaptable object is guaranteed to be an instance of one of the classes listed in the ADAPTABLE_CLASSES services registration property. The type parameter is one of the classes listed in the ADAPTER_CLASSES service registration properties.

This method may return null if the adaptable object cannot be adapted to the adapter (target) type for any reason. In this case, the implementation should log a message to the log facility noting the cause for not being able to adapt.

Note that the adaptable object is not required to implement the Adaptable interface, though most of the time this method is called by means of calling the Adaptable.adaptTo(Class) method.

Type Parameters:

AdapterType - The generic type of the adapter (target) type.

Parameters:

adaptable - The object to adapt to the adapter type.

type - The type to which the object is to be adapted.

Returns:

The adapted object or null if this factory instance cannot adapt the object.