Allow filtering of modules before initialization

Alternative for #111

README.md

@@ -112,6 +112,12 @@ public static class TestConfig {
 The `Service` was defined in the Guice module `MyModule`, and then it
 was be bound to the autowired `spam()` method when Spring started.
 
+### Filtering out modules from startup of ApplicationContext
+
+In certain cases you might need to ensure that some modules are not configured at all, even though they might not be present in the final `ApplicationContext`.
+This might be due to external code that may be hard to change that cause side effects at binding time, or for other reasons.
+To ensure this you can define a `ModuleFilter` bean that will be applied for filtering the list of modules in the Guice context before they are touched by the Spring-Guice bridge. This will ensure that no `configure()` methods are called on the filtered modules.
+
 ## Configuration Class Enhancements
 
 Note that the `Module` bean definition in the example above is 

src/main/java/org/springframework/guice/annotation/ModuleFilter.java

@@ -0,0 +1,10 @@
+package org.springframework.guice.annotation;
+
+import com.google.inject.Module;
+
+@FunctionalInterface
+public interface ModuleFilter {
+
+	boolean filter(Module module);
+
+}

src/main/java/org/springframework/guice/annotation/ModuleRegistryConfiguration.java

@@ -125,8 +125,18 @@ class ModuleRegistryConfiguration implements BeanDefinitionRegistryPostProcessor
 
 	@Override
 	public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
+
+		Map<String, ModuleFilter> moduleFilters = ((ConfigurableListableBeanFactory) registry)
+				.getBeansOfType(ModuleFilter.class);
+		if (moduleFilters.size() > 1) {
+			throw new IllegalStateException(
+					"You can only define zero or one ModuleFilter implementation. Implementations found: "
+							+ String.join(",", moduleFilters.keySet()));
+		}
+		ModuleFilter moduleFilter = moduleFilters.values().stream().findFirst().orElse(module -> true);
 		List<Module> modules = new ArrayList<>(
-				((ConfigurableListableBeanFactory) registry).getBeansOfType(Module.class).values());
+				((ConfigurableListableBeanFactory) registry).getBeansOfType(Module.class).values()).stream()
+						.filter(moduleFilter::filter).collect(Collectors.toList());
 		SpringModule module = new SpringModule((ConfigurableListableBeanFactory) registry,
 				this.enableJustInTimeBinding);
 		modules.add(module);

src/test/java/org/springframework/guice/annotation/EnableGuiceModulesTests.java

@@ -75,6 +75,14 @@ public class EnableGuiceModulesTests {
 		context.close();
 	}
 
+	@Test
+	public void moduleBeanFiltersOutModules() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(
+				FilteringModuleBeanConfig.class);
+		assertThat(context.getBean(Foo.class)).isNotNull();
+		context.close();
+	}
+
 	@Test
 	public void testInjectorCreationDoesNotCauseCircularDependencyError() {
 		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MySpringConfig.class);
@@ -151,6 +159,32 @@ public class EnableGuiceModulesTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	@EnableGuiceModules
+	protected static class FilteringModuleBeanConfig {
+
+		@Bean
+		public static MyModule2 module2() {
+			return new MyModule2();
+		}
+
+		@Bean
+		public static MyModule module() {
+			return new MyModule();
+		}
+
+		@Bean
+		public Foo service(Service service) {
+			return new Foo(service);
+		}
+
+		@Bean
+		ModuleFilter moduleFilter() {
+			return module -> !(module instanceof MyModule2);
+		}
+
+	}
+
 	protected static class MyModule extends AbstractModule {
 
 		@Override
@@ -160,6 +194,15 @@ public class EnableGuiceModulesTests {
 
 	}
 
+	protected static class MyModule2 extends AbstractModule {
+
+		@Override
+		protected void configure() {
+			throw new RuntimeException("This should not be called when filtered out!");
+		}
+
+	}
+
 	public static class SpringProvidedBean {
 
 		public SpringProvidedBean(GuiceProvidedBean guiceProvidedBean) {