feat: automatically derive the the dependent resource type if not specified

bootstrapper-maven-plugin/src/main/resources/templates/ConfigMapDependentResource.java

@@ -17,10 +17,6 @@ public class ConfigMapDependentResource
 
     public static final String KEY = "key";
 
-    public ConfigMapDependentResource() {
-        super(ConfigMap.class);
-    }
-
     @Override
     protected ConfigMap desired({{artifactClassId}}CustomResource primary,
                                 Context<{{artifactClassId}}CustomResource> context) {

docs/content/en/docs/documentation/dependent-resource-and-workflows/dependent-resources.md

@@ -136,10 +136,6 @@ Deleted (or set to be garbage collected). The following example shows how to cre
 @KubernetesDependent(labelSelector = WebPageManagedDependentsReconciler.SELECTOR)
 class DeploymentDependentResource extends CRUDKubernetesDependentResource<Deployment, WebPage> {
 
-    public DeploymentDependentResource() {
-        super(Deployment.class);
-    }
-
     @Override
     protected Deployment desired(WebPage webPage, Context<WebPage> context) {
         var deploymentName = deploymentName(webPage);

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/Utils.java

@@ -134,6 +134,27 @@ public static Class<?> getTypeArgumentFromExtendedClassByIndex(Class<?> clazz, i
     }
   }
 
+  public static Class<?> getTypeArgumentFromHierarchyByIndex(
+      Class<?> clazz, Class<?> expectedImplementedInterface, int index) {
+    Class<?> c = clazz;
+    while (!(c.getGenericSuperclass() instanceof ParameterizedType)) {
+      c = c.getSuperclass();
+    }
+    Class<?> actualTypeArgument =
+        (Class<?>) ((ParameterizedType) c.getGenericSuperclass()).getActualTypeArguments()[index];
+    if (!expectedImplementedInterface.isAssignableFrom(actualTypeArgument)) {
+      throw new IllegalArgumentException(
+          GENERIC_PARAMETER_TYPE_ERROR_PREFIX
+              + clazz.getName()
+              + "because it doesn't extend a class that is parametrized with the type that"
+              + " implements "
+              + expectedImplementedInterface.getSimpleName()
+              + ". Please provide the resource type in the constructor (e.g.,"
+              + " super(Deployment.class).");
+    }
+    return actualTypeArgument;
+  }
+
   public static Class<?> getFirstTypeArgumentFromInterface(
       Class<?> clazz, Class<?> expectedImplementedInterface) {
     return getTypeArgumentFromInterfaceByIndex(clazz, expectedImplementedInterface, 0);

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/AbstractEventSourceHolderDependentResource.java

@@ -1,8 +1,10 @@
 package io.javaoperatorsdk.operator.processing.dependent;
 
+import java.lang.reflect.ParameterizedType;
 import java.util.Optional;
 
 import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.javaoperatorsdk.operator.api.config.Utils;
 import io.javaoperatorsdk.operator.api.reconciler.Context;
 import io.javaoperatorsdk.operator.api.reconciler.EventSourceContext;
 import io.javaoperatorsdk.operator.api.reconciler.Ignore;
@@ -23,13 +25,23 @@ public abstract class AbstractEventSourceHolderDependentResource<
   private boolean isCacheFillerEventSource;
   protected String eventSourceNameToUse;
 
+  @SuppressWarnings("unchecked")
+  protected AbstractEventSourceHolderDependentResource() {
+    this(null, null);
+  }
+
   protected AbstractEventSourceHolderDependentResource(Class<R> resourceType) {
     this(resourceType, null);
   }
 
   protected AbstractEventSourceHolderDependentResource(Class<R> resourceType, String name) {
     super(name);
-    this.resourceType = resourceType;
+    if (resourceType == null) {
+      this.resourceType =
+          (Class<R>) Utils.getTypeArgumentFromHierarchyByIndex(getClass(), HasMetadata.class, 0);
+    } else {
+      this.resourceType = resourceType;
+    }
   }
 
   /**
@@ -116,4 +128,23 @@ protected void onUpdated(P primary, R updated, R actual, Context<P> context) {
   private RecentOperationCacheFiller<R> recentOperationCacheFiller() {
     return (RecentOperationCacheFiller<R>) eventSource;
   }
+
+  @SuppressWarnings("unchecked")
+  private Class<R> findFirstGenericSuperclass(
+      Class<? extends AbstractEventSourceHolderDependentResource> clazz) {
+    Class<? extends AbstractEventSourceHolderDependentResource> c = clazz;
+    while (!(c.getGenericSuperclass() instanceof ParameterizedType)) {
+      c = (Class<? extends AbstractEventSourceHolderDependentResource>) c.getSuperclass();
+    }
+    Class<R> actualTypeArgument =
+        (Class<R>) ((ParameterizedType) c.getGenericSuperclass()).getActualTypeArguments()[0];
+    if (!HasMetadata.class.isAssignableFrom(actualTypeArgument)) {
+      throw new IllegalStateException(
+          "Not possible to automatically derive the the resource type for "
+              + clazz.getName()
+              + ". Please provide the resource type in the constructor (e.g.,"
+              + " super(Deployment.class).");
+    }
+    return actualTypeArgument;
+  }
 }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/AbstractExternalDependentResource.java

@@ -21,6 +21,8 @@ public abstract class AbstractExternalDependentResource<
 
   private InformerEventSource<?, P> externalStateEventSource;
 
+  protected AbstractExternalDependentResource() {}
+
   @SuppressWarnings("unchecked")
   protected AbstractExternalDependentResource(Class<R> resourceType) {
     super(resourceType);

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/external/AbstractPollingDependentResource.java

@@ -16,6 +16,8 @@ public abstract class AbstractPollingDependentResource<R, P extends HasMetadata>
   public static final Duration DEFAULT_POLLING_PERIOD = Duration.ofMillis(5000);
   private Duration pollingPeriod;
 
+  protected AbstractPollingDependentResource() {}
+
   protected AbstractPollingDependentResource(Class<R> resourceType) {
     this(resourceType, DEFAULT_POLLING_PERIOD);
   }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/external/PerResourcePollingDependentResource.java

@@ -14,6 +14,8 @@ public abstract class PerResourcePollingDependentResource<R, P extends HasMetada
     extends AbstractPollingDependentResource<R, P>
     implements PerResourcePollingEventSource.ResourceFetcher<R, P> {
 
+  public PerResourcePollingDependentResource() {}
+
   public PerResourcePollingDependentResource(Class<R> resourceType) {
     super(resourceType);
   }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/CRUDKubernetesDependentResource.java

@@ -18,6 +18,8 @@ public abstract class CRUDKubernetesDependentResource<R extends HasMetadata, P e
     extends KubernetesDependentResource<R, P>
     implements Creator<R, P>, Updater<R, P>, GarbageCollected<P> {
 
+  public CRUDKubernetesDependentResource() {}
+
   public CRUDKubernetesDependentResource(Class<R> resourceType) {
     super(resourceType);
   }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/CRUDNoGCKubernetesDependentResource.java

@@ -20,6 +20,8 @@
 public class CRUDNoGCKubernetesDependentResource<R extends HasMetadata, P extends HasMetadata>
     extends KubernetesDependentResource<R, P> implements Creator<R, P>, Updater<R, P>, Deleter<P> {
 
+  public CRUDNoGCKubernetesDependentResource() {}
+
   public CRUDNoGCKubernetesDependentResource(Class<R> resourceType) {
     super(resourceType);
   }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/KubernetesDependentResource.java

@@ -41,6 +41,8 @@ public abstract class KubernetesDependentResource<R extends HasMetadata, P exten
   private KubernetesDependentResourceConfig<R> kubernetesDependentResourceConfig;
   private volatile Boolean useSSA;
 
+  public KubernetesDependentResource() {}
+
   public KubernetesDependentResource(Class<R> resourceType) {
     this(resourceType, null);
   }

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/api/config/ControllerConfigurationOverriderTest.java

@@ -359,21 +359,11 @@ public UpdateControl<ConfigMap> reconcile(ConfigMap resource, Context<ConfigMap>
   }
 
   public static class ReadOnlyDependent extends KubernetesDependentResource<ConfigMap, ConfigMap>
-      implements GarbageCollected<ConfigMap> {
-
-    public ReadOnlyDependent() {
-      super(ConfigMap.class);
-    }
-  }
+      implements GarbageCollected<ConfigMap> {}
 
   @KubernetesDependent(informer = @Informer(namespaces = Constants.WATCH_ALL_NAMESPACES))
   public static class WatchAllNSDependent extends KubernetesDependentResource<ConfigMap, ConfigMap>
-      implements GarbageCollected<ConfigMap> {
-
-    public WatchAllNSDependent() {
-      super(ConfigMap.class);
-    }
-  }
+      implements GarbageCollected<ConfigMap> {}
 
   @Workflow(dependents = @Dependent(type = OverriddenNSDependent.class))
   @ControllerConfiguration(
@@ -394,10 +384,6 @@ public static class OverriddenNSDependent
       implements GarbageCollected<ConfigMap> {
 
     private static final String DEP_NS = "dependentNS";
-
-    public OverriddenNSDependent() {
-      super(ConfigMap.class);
-    }
   }
 
   @Workflow(
@@ -415,12 +401,7 @@ public UpdateControl<ConfigMap> reconcile(ConfigMap resource, Context<ConfigMap>
 
     private static class NamedDependentResource
         extends KubernetesDependentResource<ConfigMap, ConfigMap>
-        implements GarbageCollected<ConfigMap> {
-
-      public NamedDependentResource() {
-        super(ConfigMap.class);
-      }
-    }
+        implements GarbageCollected<ConfigMap> {}
 
     private static class ExternalDependentResource
         implements DependentResource<Object, ConfigMap>,

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/api/config/UtilsTest.java

@@ -118,10 +118,5 @@ public UpdateControl<ConfigMap> reconcile(ConfigMap resource, Context<ConfigMap>
   }
 
   public static class TestKubernetesDependentResource
-      extends KubernetesDependentResource<Deployment, TestCustomResource> {
-
-    public TestKubernetesDependentResource() {
-      super(Deployment.class);
-    }
-  }
+      extends KubernetesDependentResource<Deployment, TestCustomResource> {}
 }

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/api/config/dependent/DependentResourceConfigurationResolverTest.java

@@ -144,20 +144,10 @@ public UpdateControl<ConfigMap> reconcile(ConfigMap resource, Context<ConfigMap>
   }
 
   public static class ConfigMapDep extends KubernetesDependentResource<ConfigMap, ConfigMap>
-      implements GarbageCollected<ConfigMap> {
-
-    public ConfigMapDep() {
-      super(ConfigMap.class);
-    }
-  }
+      implements GarbageCollected<ConfigMap> {}
 
   public static class ServiceDep extends KubernetesDependentResource<Service, ConfigMap>
-      implements GarbageCollected<ConfigMap> {
-
-    public ServiceDep() {
-      super(Service.class);
-    }
-  }
+      implements GarbageCollected<ConfigMap> {}
 
   @CustomAnnotation(value = CustomAnnotatedDep.PROVIDED_VALUE)
   @Configured(

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/GenericKubernetesResourceMatcherTest.java

@@ -186,10 +186,6 @@ HasMetadata createPrimary(String caseName) {
   private static class ServiceAccountDR
       extends KubernetesDependentResource<ServiceAccount, HasMetadata> {
 
-    public ServiceAccountDR() {
-      super(ServiceAccount.class);
-    }
-
     @Override
     protected ServiceAccount desired(HasMetadata primary, Context<HasMetadata> context) {
       return new ServiceAccountBuilder()

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/KubernetesDependentResourceTest.java

@@ -0,0 +1,81 @@
+package io.javaoperatorsdk.operator.processing.dependent.kubernetes;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.fabric8.kubernetes.api.model.apps.Deployment;
+import io.javaoperatorsdk.operator.sample.simple.TestCustomResource;
+
+import static io.javaoperatorsdk.operator.api.config.Utils.GENERIC_PARAMETER_TYPE_ERROR_PREFIX;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class KubernetesDependentResourceTest {
+
+  @ParameterizedTest
+  @ValueSource(
+      classes = {
+        TestDeploymentDependentResource.class,
+        ChildTestDeploymentDependentResource.class,
+        GrandChildTestDeploymentDependentResource.class,
+        ChildTypeWithValidKubernetesDependentResource.class,
+        ConstructorOverridedCorrectDeployementDependentResource.class
+      })
+  void checkResourceTypeDerivationWithInheritance(Class<?> clazz) throws Exception {
+    KubernetesDependentResource<?, ?> dependentResource =
+        (KubernetesDependentResource<?, ?>) clazz.getDeclaredConstructor().newInstance();
+    assertThat(dependentResource).isInstanceOf(KubernetesDependentResource.class);
+    assertThat(dependentResource.resourceType()).isEqualTo(Deployment.class);
+  }
+
+  private static class TestDeploymentDependentResource
+      extends KubernetesDependentResource<Deployment, TestCustomResource> {}
+
+  private static class ChildTestDeploymentDependentResource
+      extends TestDeploymentDependentResource {}
+
+  private static class GrandChildTestDeploymentDependentResource
+      extends ChildTestDeploymentDependentResource {}
+
+  private static class ChildTypeWithValidKubernetesDependentResource<P, T>
+      extends KubernetesDependentResource<Deployment, TestCustomResource> {}
+
+  private static class ConstructorOverridedCorrectDeployementDependentResource
+      extends KubernetesDependentResource<Deployment, TestCustomResource> {
+    public ConstructorOverridedCorrectDeployementDependentResource() {
+      super(Deployment.class);
+    }
+  }
+
+  @Test
+  void validateInvalidTypeDerivationTypesThrowException() {
+    assertThatThrownBy(() -> new InvalidChildTestDeploymentDependentResource())
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessage(
+            GENERIC_PARAMETER_TYPE_ERROR_PREFIX
+                + InvalidChildTestDeploymentDependentResource.class.getName()
+                + "because it doesn't extend a class that is parametrized with the type that"
+                + " implements "
+                + HasMetadata.class.getSimpleName()
+                + ". Please provide the resource type in the constructor (e.g.,"
+                + " super(Deployment.class).");
+    assertThatThrownBy(() -> new InvalidGrandChildTestDeploymentDependentResource())
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessage(
+            GENERIC_PARAMETER_TYPE_ERROR_PREFIX
+                + InvalidGrandChildTestDeploymentDependentResource.class.getName()
+                + "because it doesn't extend a class that is parametrized with the type that"
+                + " implements "
+                + HasMetadata.class.getSimpleName()
+                + ". Please provide the resource type in the constructor (e.g.,"
+                + " super(Deployment.class).");
+  }
+
+  private static class InvalidChildTestDeploymentDependentResource
+      extends ChildTypeWithValidKubernetesDependentResource<Object, Object> {}
+
+  private static class InvalidGrandChildTestDeploymentDependentResource
+      extends InvalidChildTestDeploymentDependentResource {}
+}

operator-framework/src/test/java/io/javaoperatorsdk/operator/baseapi/unmodifiabledependentpart/UnmodifiablePartConfigMapDependent.java

@@ -14,10 +14,6 @@ public class UnmodifiablePartConfigMapDependent
   public static final String UNMODIFIABLE_INITIAL_DATA_KEY = "initialDataKey";
   public static final String ACTUAL_DATA_KEY = "actualDataKey";
 
-  public UnmodifiablePartConfigMapDependent() {
-    super(ConfigMap.class);
-  }
-
   @Override
   protected ConfigMap desired(
       UnmodifiableDependentPartCustomResource primary,

operator-framework/src/test/java/io/javaoperatorsdk/operator/config/BaseConfigurationServiceTest.java

@@ -414,12 +414,7 @@ public UpdateControl<ConfigMapReader> reconcile(
 
     @KubernetesDependent(useSSA = BooleanWithUndefined.TRUE)
     public static class WithAnnotation
-        extends CRUDKubernetesDependentResource<ConfigMap, ConfigMapReader> {
-
-      public WithAnnotation() {
-        super(ConfigMap.class);
-      }
-    }
+        extends CRUDKubernetesDependentResource<ConfigMap, ConfigMapReader> {}
   }
 
   public static class MissingAnnotationReconciler implements Reconciler<ConfigMap> {
@@ -443,18 +438,10 @@ public UpdateControl<ConfigMap> reconcile(ConfigMap resource, Context<ConfigMap>
     }
 
     private static class DefaultDependent
-        extends KubernetesDependentResource<ConfigMapReader, ConfigMap> {
-      public DefaultDependent() {
-        super(ConfigMapReader.class);
-      }
-    }
+        extends KubernetesDependentResource<ConfigMapReader, ConfigMap> {}
 
     @KubernetesDependent(useSSA = BooleanWithUndefined.FALSE)
-    private static class NonSSADependent extends KubernetesDependentResource<Service, ConfigMap> {
-      public NonSSADependent() {
-        super(Service.class);
-      }
-    }
+    private static class NonSSADependent extends KubernetesDependentResource<Service, ConfigMap> {}
   }
 
   public static class TestRetry implements Retry, AnnotationConfigurable<TestRetryConfiguration> {

operator-framework/src/test/java/io/javaoperatorsdk/operator/dependent/bulkdependent/ConfigMapDeleterBulkDependentResource.java

@@ -21,10 +21,6 @@ public class ConfigMapDeleterBulkDependentResource
   public static final String ADDITIONAL_DATA_KEY = "additionalData";
   public static final String INDEX_DELIMITER = "-";
 
-  public ConfigMapDeleterBulkDependentResource() {
-    super(ConfigMap.class);
-  }
-
   @Override
   public Map<String, ConfigMap> desiredResources(
       BulkDependentTestCustomResource primary, Context<BulkDependentTestCustomResource> context) {