Class TypeLiteral<T>
- java.lang.Object
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- org.apache.commons.lang3.reflect.TypeLiteral<T>
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- Type Parameters:
T
- the type
- All Implemented Interfaces:
Typed<T>
public abstract class TypeLiteral<T> extends java.lang.Object implements Typed<T>
Type literal comparable to
javax.enterprise.util.TypeLiteral
, made generally available outside the JEE context. Allows the passing around of a "token" that represents a type in a typesafe manner, as opposed to passing the (non-parameterized)Type
object itself. Consider:You might see such a typesafe API as:
class Typesafe { <T> T obtain(Class<T> type, ...); }
Consumed in the manner of:Foo foo = typesafe.obtain(Foo.class, ...);
Yet, you run into problems when you want to do this with a parameterized type:List<String> listOfString = typesafe.obtain(List.class, ...); // could only give us a raw List
java.lang.reflect.Type
might provide some value:Type listOfStringType = ...; // firstly, how to obtain this? Doable, but not straightforward. List<String> listOfString = (List<String>) typesafe.obtain(listOfStringType, ...); // nongeneric Type would necessitate a cast
The "type literal" concept was introduced to provide an alternative, i.e.:class Typesafe { <T> T obtain(TypeLiteral<T> type, ...); }
Consuming code looks like:List<String> listOfString = typesafe.obtain(new TypeLiteral<List<String>>() {}, ...);
This has the effect of "jumping up" a level to tie a
java.lang.reflect.Type
to a type variable while simultaneously making it short work to obtain aType
instance for any given type, inline.Additionally
TypeLiteral
implements theTyped
interface which is a generalization of this concept, and which may be implemented in custom classes. It is suggested that APIs be defined in terms of the interface, in the following manner:<T> T obtain(Typed<T> typed, ...);
- Since:
- 3.2
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Field Summary
Fields Modifier and Type Field Description java.lang.reflect.Type
value
Represented type.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
equals(java.lang.Object obj)
java.lang.reflect.Type
getType()
Gets theType
represented by this entity.int
hashCode()
java.lang.String
toString()
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