CODEWITHSUNDEEP
javasingletonguice
saurabh agarwal
saurabh agarwal

Reputation: 2184

Creating Singleton in java using guice

import com.google.inject.Injector;
import static com.google.inject.Guice.createInjector;

public final class BatchFactory {

      private static class Holder {
          private static final Injector INJECTOR = createInjector(new BatchModule());
          private static final batchProvider PROVIDER_INSTANCE = INJECTOR
                  .getInstance(BatchProvider.class);
      }

      public static BatchProvider getProviderInstance() {
          return Holder.PROVIDER_INSTANCE;
      }
  }

public class BatchModule extends AbstractModule {
      @Override
      protected void configure() {
          bind(BatchProvider.class).to(
                  BatchProviderImpl.class);
      }
  }

BatchProvider is the Interface and BatchProviderImpl is the class implementation.

Here I am using a class BatchFactory to create the @Singleton instance of BatchProviderImpl class.

Can I use @Singleton annotation of google guice to make BatchFactory class @Singleton

Upvotes: 1

Views: 6317

Answers (1)

tkruse
tkruse

Reputation: 10695

See the duplicate question, you can do 

bind(Service.class).to(ServiceImpl.class).in(Singleton.class);

Or:

@Provides @Singleton
public ServiceImpl providesService() {
    return new ServiceImpl();
}

Upvotes: 3

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