Injecting Clazz<?> - Githubissues

Guice seems unable to inject Clazz<?> values. The example below
demonstrates a use case. The code was run with guice-1.0.

A possible fix as discussed with Kevin is to treat bindings of
Clazz.class as providing @Inject Clazz<?>.

package com.example;

import com.google.inject.AbstractModule;
import com.google.inject.Guice;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.Key;
import com.google.inject.TypeLiteral;

import junit.framework.TestCase;

public class GuiceCaptureTest extends TestCase {
 public void testAnyTypeCapture() throws Exception {
   Injector injector = Guice.createInjector(new Module());
   assertNotNull(injector.getInstance(  // this works
       Key.<Parameterized<String>>get(new
TypeLiteral<Parameterized<String>>() {})));
   assertNotNull(injector.getInstance(Foo.class).p); // this bombs,
exception below
 }

 static class Module extends AbstractModule {
   @Override
   protected void configure() {
     // This binding is useless because a TypeLiteral has to be fully
specified.
     bind(new TypeLiteral<Parameterized<?>>() {})
       .to(ParameterizedImpl.class);
     bind(new TypeLiteral<Parameterized<String>>() {})
       .to(ParameterizedImpl.class);
     // This is the proposed binding which doesn't work yet.
     bind(Parameterized.class).to(ParameterizedImpl.class);
   }
 }

 interface Parameterized<T> {
   T check();
 }

 static class ParameterizedImpl implements Parameterized<String> {
   @Override
   public String check() {
     return null;
   }
 }

 static class Foo {
   private Parameterized<?> p;

   @Inject Foo(Parameterized<?> p) {
     this.p = p;
   }
 }
}

/*
com.google.inject.ConfigurationException:
Error at com.example.GuiceCaptureTest$Foo.<init>(GuiceCaptureTest.java:47)
Binding to
com.example.GuiceCaptureTest.com.example.GuiceCaptureTest$Parameterized<?>
not found.
No bindings to that type were found.
 at
com.google.inject.BinderImpl$RuntimeErrorHandler.handle(BinderImpl.java:426)
 at com.google.inject.AbstractErrorHandler.handle(AbstractErrorHandler.java:30)
 at com.google.inject.ErrorMessages.handleMissingBinding(ErrorMessages.java:46)
 at
com.google.inject.InjectorImpl$MissingDependencyException.handle(InjectorImpl.ja
va:791)
 at
com.google.inject.ConstructorInjector.createParameterInjector(ConstructorInjecto
r.java:66)
 at com.google.inject.ConstructorInjector.<init>(ConstructorInjector.java:38)
 at com.google.inject.InjectorImpl$7.create(InjectorImpl.java:601)
 at com.google.inject.InjectorImpl$7.create(InjectorImpl.java:594)
 at com.google.inject.util.ReferenceCache.create(ReferenceCache.java:53)
 at
com.google.inject.util.AbstractReferenceCache.internalCreate(AbstractReferenceCa
che.java:59)
 at
com.google.inject.util.AbstractReferenceCache.get(AbstractReferenceCache.java:11
6)
 at com.google.inject.InjectorImpl.getConstructor(InjectorImpl.java:765)
 at com.google.inject.InjectorImpl.getImplicitBinding(InjectorImpl.java:973)
 at com.google.inject.InjectorImpl.getInternalFactory(InjectorImpl.java:308)
 at com.google.inject.InjectorImpl.getProvider(InjectorImpl.java:693)
 at com.google.inject.InjectorImpl.getProvider(InjectorImpl.java:689)
 at com.google.inject.InjectorImpl.getInstance(InjectorImpl.java:728)
 at com.example.GuiceCaptureTest.testAnyTypeCapture(GuiceCaptureTest.java:17)
*/
Original issue reported on code.google.com by blackgne...@gmail.com on 24 Oct 2007 at 8:47
bineanzhou / google-guice

Injecting Clazz<?> #159
