Fix lost Supplier<T> type info in Guice2Spring direction

src/test/java/org/springframework/guice/ProvidesSupplierWiringTests.java

@@ -0,0 +1,111 @@
+package org.springframework.guice;
+
+import com.google.inject.AbstractModule;
+import com.google.inject.Key;
+import com.google.inject.Provides;
+import com.google.inject.TypeLiteral;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.guice.annotation.EnableGuiceModules;
+import org.springframework.guice.injector.SpringInjector;
+
+import javax.inject.Singleton;
+import java.util.function.Supplier;
+
+/**
+ * Test Generics (e.g., Supplier<T>) not losing type info across bridge in both directions
+ *
+ * @author Howard Yuan
+ */
+public class ProvidesSupplierWiringTests {
+
+    //Test Guice -> Spring direction
+    @Test
+    public void testProvidesSupplier() {
+        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(ModulesConfig.class, FooBar.class);
+        Foo foo = (Foo)context.getBean(Foo.class);
+        Bar bar = (Bar)context.getBean(Bar.class);
+    }
+
+    @Configuration
+    @EnableGuiceModules
+    static class ModulesConfig {
+        @Bean
+        TestConfig testConfig() {
+            return new TestConfig();
+        }
+    }
+
+    @Configuration
+    static class FooBar {
+        @Bean
+        Foo foo(Supplier<Foo> supplier) {
+            return supplier.get();
+        }
+
+        @Bean
+        Bar bar(Supplier<Bar> supplier) {
+            return supplier.get();
+        }
+    }
+
+    static class TestConfig extends AbstractModule {
+        @Override
+        protected void configure() {
+        }
+
+        @Singleton
+        @Provides
+        Supplier<Foo> getFoo() {
+            return ()->new Foo();
+        }
+
+        @Singleton
+        @Provides
+        Supplier<Bar> getBar() {
+            return ()->new Bar();
+        }
+    }
+
+    static class Foo {
+    }
+
+    static class Bar {
+
+    }
+
+    //Test Spring -> Guice direction
+    //ToDo -- Today this direction doesn't work without further work. Ignore the test for now.
+    @Ignore
+    @Test
+    public void testProvidesSupplierSpring() {
+        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(FooBarSpring.class);
+        SpringInjector injector = new SpringInjector(context);
+        Foo_Spring fooSpring = injector.getInstance(Key.get(new TypeLiteral<Supplier<Foo_Spring>>(){})).get();
+        Bar_Spring barSpring = injector.getInstance(Key.get(new TypeLiteral<Supplier<Bar_Spring>>(){})).get();
+    }
+
+    @Configuration
+    static class FooBarSpring {
+        @Bean
+        Supplier<Foo_Spring> fooSpring() {
+            return ()->new Foo_Spring();
+        }
+
+        @Bean
+        Bar_Spring barSpring() {
+            return new Bar_Spring();
+        }
+    }
+
+    static class Foo_Spring {
+    }
+
+    static class Bar_Spring {
+
+    }
+
+}