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What is Governator?

Governator is a library of extensions and utilities that enhance Google Guice to provide:

• Classpath scanning and automatic binding
• Lifecycle management
• Injector bootstrapping
• Configuration to field mapping
• Field validation
• Parallelized object warmup
• Lazy singleton
• Fine grained, more concurrent singleton
• Generic binding annotations

Features

Classpath scanning and automatic binding

Governator introduces the annotations @AutoBindSingleton and @AutoBind. See the Auto Binding wiki for details.

Lifecycle management

Governator adds support for the standard annotations: @PostConstruct, @PreDestroy and @Resource. See the Lifecycle Management wiki for details.

Injector bootstrapping

Governator simplifies bootstrapping the Guice injector by providing a single Builder on which various operations can be applied to determine the final set of modules used to create the injector. These include, adding modules, overriding modules (coming soon), module transitive dependencies, suites of configuration sets, module transformations, post injector creation hooks, etc. In addition Governator provides an annotation based approach to further simply bootstrapping an application via a single main configuration class.

Configuration to field mapping

Governator introduces a new annotation @Configuration that can be used to annotate class fields. Governator will assign the fields using configuration from property files, etc. Another annotation is also introduced, @PreConfiguration, for methods to be called prior to configuration assignment. See the Configuration Mapping wiki for details.

Field validation

Governator supports the javax.validation annotations (JSR 303). Fields annotated with validation annotations will get validated via the Hibernate Validator. See the Field Validation wiki for details.

Parallelized object warmup

Governator introduces the new annotation @WarmUp. Methods annotated with @WarmUp will get executed (in parallel) after injected by Guice. See the Warm Up wiki for details.

Lazy Singletons

Governator adds a LazySingleton annotation and scope. This is the opposite of Guice’s Eager Singletons. Lazy singletons are not created until just before they are to be injected regardless of Guice’s Stage. See the Lazy Singleton wiki for details.

Fine Grained, More Concurrent Singletons

Guice’s default Singleton scope synchronizes all object creation on a single lock (InternalInjectorCreator.class). It does this to avoid deadlocks with circular dependencies. FineGrainedLazySingleton instead locks on the key so that multiple singletons can be created concurrently. See the Concurrent Singleton wiki for details.

Generic Binding Annotations

The com.netflix.governator.annotations.binding package contains a set of generic binding annotations that you might find useful. These might be more clear and more maintainable to users than using Guice’s @Named. The full set can be found here: binding-annotations

Module transitive dependencies

The Governator bootstrap phase makes it easy to pull in Guice modules and their transitive dependencies without having to worry about duplicate bindings.

Application container

Simplified integration with various application containers by adding a single Guice module. Support is provided for standalone applications.

Requirements/Prerequisites

It’s assumed that you are familiar with Google Guice.

Maven / Artifacts

Governator binaries are published to Maven Central.

GroupID/Org	com.netflix.governator
ArtifactID/Name	governator