Home > Java Get > Java Get Runtime Class Of Generic Type

Java Get Runtime Class Of Generic Type

Contents

Since we're a parametric type we can safely cast ourselves to ParameterizedType (line 3). Something like public static GenericClass of(Class type) {...} and then call it as such: GenericClass var = GenericClass.of(String.class). Parameters: type - the type to create a String representation for, not null Returns: String Since: 3.2 toLongString public staticStringtoLongString(TypeVariablevar) Format a TypeVariable including its GenericDeclaration. Such modifications of the class representation would however be incomprehensible to older JREs and thus break the backwards compatibility of Java applications. his comment is here

import com.google.common.reflect.TypeToken; import java.lang.reflect.Type; public class GenericClass { private final TypeToken typeToken = new TypeToken(getClass()) { }; private final Type type = typeToken.getType(); // or getRawType() to return Classfind this

Java Parameterizedtype

if (type.isAssignableFrom(result.getClass())) { return (T)result; } else { // handle the error } } share|improve this answer answered Apr 2 '14 at 12:45 Abel ANEIROS 1,56611112 add a comment| up vote Browse other questions tagged java generics reflection or ask your own question. static Typed wrap(Classtype) Wrap the specified Class in a Typed wrapper. We're here because we're desperate. –Addison Apr 7 '15 at 7:15 4 I get this exception : Exception in thread "main" java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType not sure

The code itself though is just plain nasty, with all the explicit casting and using hardcoded array indexing. static boolean equals(href="http://docs.oracle.com/javase/7/docs/api/java/lang/reflect/Type.html?is-external=true" title="class or interface in java.lang.reflect">Typet1, Typet2) Check equality of types. Of course, this only works if the total number of possible classes is limited. Java Reflection Get Generic Type extends Map

Parameters: wildcardType - the subject wildcard type, not null Returns: a non-empty array containing the upper bounds of the wildcard type. extends Class> 0 How to tell the class of a generic object in Java 0 Get generic type information see more linked questions… Related 605How do I use reflection to call I've also added a note clarifying that you must instantiate a subclass (as shown). http://stackoverflow.com/questions/16799129/java-generics-get-classt-of-generic-parameter import org.springframework.core.GenericTypeResolver; public abstract class AbstractHibernateDao implements DataAccessObject { @Autowired private SessionFactory sessionFactory; private final Class genericType; private final String RECORD_COUNT_HQL; private final String FIND_ALL_HQL; @SuppressWarnings("unchecked") public AbstractHibernateDao() {

In contrast, now MyStringSubSubClass stores a reference U = String while MyGenericSubClass only knows that U = T. Getgenericsuperclass Using the /tmp folder for backups, recommended? One generic DAO implementation exists, containing common operations like findById, persist, remove, etc. Not the answer you're looking for?

Java Type To Class

It returns the generic type parameters of the class, but not the actual type of T. http://stackoverflow.com/questions/3941384/how-to-get-the-generic-type-at-runtime Line 6 gets the array of types mapped into our generics, in order as declared in the class code. Java Parameterizedtype But how to do that? Java Cannot Select From Parameterized Type Linked 50 Java generics - get class? 4 How to get class of T from Vector in java 0 how to write T.class in java? 1 Get class type of generic

Or more specifically, the running application will determine that ArrayList.class is equal to itself and return true, despite of String.class != Integer.class. http://analysedesgeeks.com/java-get/java-get-generic-type-runtime.html getImplicitBounds public staticType[]getImplicitBounds(TypeVariabletypeVariable) Returns an array containing the sole type of Object if TypeVariable.getBounds() returns an empty array. But four guys can't be wrong. In it, you'll get: The week's top questions and answers Important community announcements Questions that need answers see an example newsletter By subscribing, you agree to the privacy policy and terms Java Get Generic Class Name

RegardsMakarand Myšlenky dne otce Fura » Blog Archive » Oříšek v reflexní analýze generik - Reply March 19, 2010 at 8:23 am [...] Tohle je tak trošku předskokan prvně uvedeného článku If you can, please upload videos of these patterns with elaborate examples. He is referring to the type information I mention in the second part of my answer, but that is not what the question asks for. –Michael Borgwardt Aug 31 '11 at weblink This includes for example method or field definitions.

Value types an specialized code for those is at least equally important for why .NET is better in the generics area. –Joachim Sauer Jul 19 '12 at 14:34 @JoachimSauer, Java Get Generic Type Of List Doesn't English have vowel harmony? The produced bytecode, therefore, contains only ordinary classes, interfaces, and methods.

But the information is actually present as metadata and can be accessed via reflection (but it is still not used for type-checking).

Oktober 2008 um 08:50 Thanks for the tip, Robert. Antworten janmaterne Says: 16. interface Factory { T apply(); } void List make10(Factory factory) { List result = new ArrayList(); for (int a = 0; a < 10; a++) result.add(factory.apply()); return result; } class Generictyperesolver Returns: a Map of the type arguments to their respective type variables.

Examples Java Code Geeks is not connected to Oracle Corporation and is not sponsored by Oracle Corporation. If a subclass knows the generic arguments of its super class, they can be retreived via reflections. It gets tricky if your concrete children are be an arbitrary number of hops away, or if you're concrete and not final, and especially tricky if you expect any of your check over here for (Type baseType : actualTypeArguments) { while (resolvedTypes.containsKey(baseType)) { baseType = resolvedTypes.get(baseType); } typeArgumentsAsClasses.add(getClass(baseType)); } return typeArgumentsAsClasses; } } share|improve this answer answered Feb 21 '13 at 16:59 Ondrej Bozek 3,82322248

Spring solution My project was using Spring which is even better as Spring has a handy utility method for finding the type. docs.guava-libraries.googlecode.com/git/javadoc/com/google/… –Cody A. In the design patterns though I miss a few of the important patterns like Factory, Abstract Factory, Facade, etc. This comes back as a Type.

For this example we pull out the first parameter. But it may be helpful for others who stumple upon the question and are looking for my solution. –Matthias Jan 24 '14 at 8:30 getClass().getGenericSuperclass() will achieve the same You are of course right, it should of course be classOfInterest != subClass.getSuperclass() The intent is to iterate through the class hierarchy until the direct sub class of the "class of static Map<TypeVariable,Type> determineTypeArguments(Classcls,

static Type getArrayComponentType(Typetype) Get the array component type of type. The import statement is included so you should be able to easily find the docs and check yourself. Otherwise, it returns the result of WildcardType.getUpperBounds() passed into normalizeUpperBounds(java.lang.reflect.Type[]). getTypeArguments public staticMap,Type>getTypeArguments(Typetype, ClasstoClass) Gets the type arguments of a class/interface based on a subtype.

Email address: Recent Jobs No job listings found.Join Us With 1,240,600 monthly unique visitors and over 500 authors we are placed among the top Java related sites around. Find the sum of all numbers below n that are a multiple of some set of numbers Should I remove "Name" field in my newsletter sign up form? Type Parameters: T - generic type Parameters: type - to wrap Returns: Typed Since: 3.2 Skip navigation links Overview Package Class Use Tree Deprecated Index Help PrevClass NextClass Frames NoFrames AllClasses Dezember 2008 um 22:43 Let's try that again but with better HTML🙂 public class Test { private Class aClass; public Test(Class aClass){ this.aClass = aClass; } public static void main(String[] args)

In our case, we'll use the getGenericSuperclass method on a class extending our GenericJpaDao class. There is a rich literature on the subject, and some people are dissatisfied with the current state, some says that actually it's a lure and there is no real need for The Javadoc of the method states the following:

* If the superclass is a parameterized type, the Type * object returned must accurately reflect the actual type * parameters used in The key is that when Java determines this Type object, it uses type information present in the child to associate type information with our type parameters in the new ParameterizedType instance.