Add Base DI setup, use guice as DI using hk2-guice bridge

Author: G8XSU

app/build.gradle

@@ -35,6 +35,7 @@ dependencies {
   implementation "com.google.protobuf:protobuf-java:$protobufVersion"
 
   implementation('org.glassfish.jersey.containers:jersey-container-servlet:3.1.0')
+  implementation('org.glassfish.jersey.inject:jersey-hk2:3.1.0')
 
   //jOOQ & Postgres impl deps
   implementation "org.jooq:jooq:$jooqVersion"
@@ -44,6 +45,10 @@ dependencies {
   jooqGenerator "org.postgresql:postgresql:$postgresVersion"
 
   implementation "com.google.inject:guice:$guiceVersion"
+  implementation "org.glassfish.hk2:guice-bridge:3.0.3"
+
+  compileOnly 'org.projectlombok:lombok:1.18.24'
+  annotationProcessor 'org.projectlombok:lombok:1.18.24'
 
   compileOnly 'org.projectlombok:lombok:1.18.24'
   annotationProcessor 'org.projectlombok:lombok:1.18.24'

app/src/main/java/org/vss/VSSApplication.java

@@ -1,10 +1,31 @@
 package org.vss;
 
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import jakarta.inject.Inject;
 import jakarta.ws.rs.ApplicationPath;
+import org.glassfish.hk2.api.ServiceLocator;
 import org.glassfish.jersey.server.ResourceConfig;
+import org.jvnet.hk2.guice.bridge.api.GuiceBridge;
+import org.jvnet.hk2.guice.bridge.api.GuiceIntoHK2Bridge;
+import org.vss.guice.BaseModule;
 
 @ApplicationPath("/")
 public class VSSApplication extends ResourceConfig {
-  public VSSApplication() {
+
+  @Inject
+  public VSSApplication(ServiceLocator serviceLocator) {
+    packages("org.vss");
+    Injector injector = Guice.createInjector(new BaseModule());
+    initGuiceIntoHK2Bridge(serviceLocator, injector);
+  }
+
+  // By default, Jersey framework uses HK2 for dependency injection.
+  // To use Guice as our dependency injection framework, we provide guice injector to hk2-bridge.
+  // So that hk2 can query guice injector for creating/injecting objects.
+  private void initGuiceIntoHK2Bridge(ServiceLocator serviceLocator, Injector injector) {
+    GuiceBridge.getGuiceBridge().initializeGuiceBridge(serviceLocator);
+    GuiceIntoHK2Bridge guiceBridge = serviceLocator.getService(GuiceIntoHK2Bridge.class);
+    guiceBridge.bridgeGuiceInjector(injector);
   }
 }

app/src/main/java/org/vss/guice/BaseModule.java

@@ -0,0 +1,13 @@
+package org.vss.guice;
+
+import com.google.inject.AbstractModule;
+import com.google.inject.Singleton;
+import org.vss.KVStore;
+import org.vss.impl.postgres.PostgresBackendImpl;
+
+public class BaseModule extends AbstractModule {
+  @Override
+  protected void configure() {
+    bind(KVStore.class).to(PostgresBackendImpl.class).in(Singleton.class);
+  }
+}