io.github.firemaples.utils

Class TypeReference<T>

java.lang.Object

io.github.firemaples.utils.TypeReference<T>

All Implemented Interfaces:

java.lang.Comparable<TypeReference<T>>

public abstract class TypeReference<T>
extends java.lang.Object
implements java.lang.Comparable<TypeReference<T>>

This class is used to pass full generics type information, and avoid problems with type erasure (that basically removes most usable type references from runtime Class objects). It is based on ideas from http://gafter.blogspot.com/2006/12/super-type-tokens.html, Additional idea (from a suggestion made in comments of the article) is to require bogus implementation of Comparable (any such generic interface would do, as long as it forces a method with generic type to be implemented). to ensure that a Type argument is indeed given.

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Usage is by sub-classing: here is one way to instantiate reference to generic type List<Integer>:

  TypeReference ref = new TypeReference<List<Integer>>() { };
 

which can be passed to methods that accept TypeReference.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TypeReference()

Method Summary

Modifier and Type	Method and Description
int	compareTo(TypeReference<T> o) The only reason we define this method (and require implementation of Comparable) is to prevent constructing a reference without type information.
java.lang.reflect.Type	getType()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TypeReference

protected TypeReference()

Method Detail

getType

public java.lang.reflect.Type getType()

compareTo

public int compareTo(TypeReference<T> o)

The only reason we define this method (and require implementation of Comparable) is to prevent constructing a reference without type information.

Specified by:

compareTo in interface java.lang.Comparable<TypeReference<T>>