Guice multiBind not working when use @Inject(optional=true)

[Dilanka Muthukumarana]

Hi All,

Currently I am working in Guice injection related development and experiencing injection problem with multiBind  with optional= true.

In guice-4.0, I have seen skipping injection if it is optional.

code location: MembersInjectorStore.java

Method: 

/**

 * Returns the injectors for the specified injection points.
 */
ImmutableList<SingleMemberInjector> getInjectors(
    Set<InjectionPoint> injectionPoints, Errors errors) {
  List<SingleMemberInjector> injectors = Lists.newArrayList();
  for (InjectionPoint injectionPoint : injectionPoints) {
    try {
      Errors errorsForMember = injectionPoint.isOptional()
          ? new Errors(injectionPoint)
          : errors.withSource(injectionPoint);
      SingleMemberInjector injector = injectionPoint.getMember() instanceof Field
          ? new SingleFieldInjector(this.injector, injectionPoint, errorsForMember)
          : new SingleMethodInjector(this.injector, injectionPoint, errorsForMember);
      injectors.add(injector);
    } catch (ErrorsException ignoredForNow) {
      // ignored for now
    }
  }
  return ImmutableList.copyOf(injectors);
}

My code is like below:

private Set<WarningInfoClientPlugin> warningInfoClientPlugins;

@Inject(optional = true)
public void setWarningPlugins(final Set<WarningInfoClientPlugin> warningInfoClientPlugins)
{
  this.warningInfoClientPlugins = warningInfoClientPlugins;
}

Code is perfectly working without optional = true attribute.
Appreciate your help on this. Thank you.

Regards,
Dilanka

[Dilanka Muthukumarana]

Hi Again,

I am using configuration as below:

multibind(WarningInfoClientPlugin.class, EPedDoseValidationWarningPlugin.class);

 protected final <T> void multibind(final Class<T> classType, final Class<?>... implementations)

  {

    final Multibinder<T> pluginBinder = Multibinder.newSetBinder(binder(), classType);

    for (final Class<?> impl : implementations)

    {

      pluginBinder.addBinding().to((Class<T>)impl);

    }

  }

Thanks and Regards,

Dilanka

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Regards,                              
Dilanka Muthukumarana                                                      

      

[Dilanka Muthukumarana]

Hi All,

By further debug information, I have found that below error is throwing.

Unable to create binding for java.util.Set< <package>  .WarningInfoClientPlugin>. 

It was already configured on one or more child injectors or private modules

    bound at <package>.AbstractInjectModule.multibind(AbstractInjectModule.java:130) 

(via modules: com.google.inject.util.Modules$OverrideModule -> com.google.inject.util.Modules$OverrideModule -> com.google.inject.util.Modules$CombinedModule ->  <package> .Configuration -> com.google.inject.multibindings.Multibinder$RealMultibinder)

  If it was in a PrivateModule, did you forget to expose the binding?

Any idea about it, Implementation of class is at another module, do I need to add another configuration or something like that?

Regards,

Dilanka

[Dilanka Muthukumarana]

I guess this bug is the reason:

https://github.com/google/guice/issues/847

Can I know whether it is fixed or not?

Regards,

Dilanka