Package org.apache.tapestry5.commons
Interface ObjectProvider
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- All Known Implementing Classes:
ApplicationMessageCatalogObjectProvider
,AssetObjectProvider
,AutobuildObjectProvider
,EntityManagerObjectProvider
,ServiceAnnotationObjectProvider
,StaticObjectProvider
,SymbolObjectProvider
,ValueObjectProvider
public interface ObjectProvider
Object providers represent an alternate way to locate an object provided somewhere in theRegistry
. Instead of using a just the service id to gain access to a service within the Registry, object providers in different flavors are capable of vending, or even creating, objects of disparate types from disparate sources. Object providers are consulted in a strict order, and the first non-null result is taken. In many cases, an object provider searches for additional annotations on the element (usually a parameter, or perhaps a field) for which a value is required.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description <T> T
provide(java.lang.Class<T> objectType, AnnotationProvider annotationProvider, ObjectLocator locator)
Provides an object based on an expression.
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Method Detail
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provide
<T> T provide(java.lang.Class<T> objectType, AnnotationProvider annotationProvider, ObjectLocator locator)
Provides an object based on an expression. The process of providing objects occurs within a particular context, which will typically be a service builder method, service contributor method, or service decorator method. The locator parameter provides access to the services visible to that context.- Type Parameters:
T
-- Parameters:
objectType
- the expected object typeannotationProvider
- provides access to annotations (typically, the field or parameter to which an injection-related annotation is attached); annotations on the field or parameter may also be used when resolving the desired objectlocator
- locator for the context in which the provider is being used- Returns:
- the requested object, or null if this object provider can not supply an object
- Throws:
java.lang.RuntimeException
- if the expression can not be evaluated, or the type of object identified is not assignable to the type specified by the objectType parameter
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