Package edu.internet2.middleware.grouperClientExt.org.apache.commons.lang3.reflect

Class TypeLiteral<T>

java.lang.Object
edu.internet2.middleware.grouperClientExt.org.apache.commons.lang3.reflect.TypeLiteral<T>
Type Parameters:
T - the type
All Implemented Interfaces:
Typed<T>
public abstract class TypeLiteral<T> extends 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 a Type instance for any given type, inline.

Additionally TypeLiteral implements the Typed 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

  • Field Details

    • value

      public final Type value
      Represented type.

  • Constructor Details

    • TypeLiteral

      protected TypeLiteral()
      The default constructor.

  • Method Details

    • equals

      public final boolean equals(Object obj)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • getType

      public Type getType()
      Description copied from interface: Typed
      Gets the Type represented by this entity.
      Specified by:
      getType in interface Typed<T>
      Returns:
      Type