Ensure custom content-types work (#6618)

* Add some more valdiations when registering content-type-bundles.
* Add a page on the project web site for registered content-types.
* Add tests in `:nessie-model` + `:nessie-versioned-spi` to verify that
  custom content-type-bundles and custom content-serializer-bundles
  work.

Fixes #6591

api/model/build.gradle.kts

@@ -49,6 +49,14 @@ dependencies {
   annotationProcessor(libs.immutables.value.processor)
 
   testCompileOnly(libs.microprofile.openapi)
+  testCompileOnly(libs.immutables.value.annotations)
+  testAnnotationProcessor(libs.immutables.value.processor)
+  testCompileOnly(libs.jakarta.ws.rs.api)
+  testCompileOnly(libs.javax.ws.rs)
+  testCompileOnly(libs.jakarta.validation.api)
+  testCompileOnly(libs.javax.validation.api)
+  testCompileOnly(libs.jakarta.annotation.api)
+  testCompileOnly(libs.findbugs.jsr305)
 
   testImplementation(platform(libs.junit.bom))
   testImplementation(libs.bundles.junit.testing)

api/model/src/main/java/org/projectnessie/model/Content.java

@@ -20,6 +20,7 @@
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 import com.fasterxml.jackson.databind.annotation.JsonTypeIdResolver;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import javax.annotation.Nullable;
@@ -34,7 +35,13 @@
 @Schema(
     type = SchemaType.OBJECT,
     title = "Content",
-    oneOf = {IcebergTable.class, DeltaLakeTable.class, IcebergView.class, Namespace.class},
+    anyOf = {
+      IcebergTable.class,
+      DeltaLakeTable.class,
+      IcebergView.class,
+      Namespace.class,
+      Map.class
+    },
     discriminatorMapping = {
       @DiscriminatorMapping(value = "ICEBERG_TABLE", schema = IcebergTable.class),
       @DiscriminatorMapping(value = "DELTA_LAKE_TABLE", schema = DeltaLakeTable.class),

api/model/src/main/java/org/projectnessie/model/types/ContentTypeBundle.java

@@ -18,10 +18,7 @@
 /**
  * Used to provide custom {@link org.projectnessie.model.Content} implementations via the Java
  * {@link java.util.ServiceLoader service loader} mechanism.
- *
- * <p><em>The functionality to actually use custom types is incomplete as long as ther is no
- * store-worker support for custom content. </em>
  */
 public interface ContentTypeBundle {
-  void register(ContentTypes.Registrar registrar);
+  void register(ContentTypeRegistry contentTypeRegistry);
 }

api/model/src/main/java/org/projectnessie/model/types/ContentTypeRegistry.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2023 Dremio
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.projectnessie.model.types;
+
+import org.projectnessie.model.Content;
+
+/** An implementation of this interface is passed to {@link ContentTypeBundle}s. */
+public interface ContentTypeRegistry {
+  void register(Class<? extends Content> type);
+}

api/model/src/main/java/org/projectnessie/model/types/ContentTypes.java

@@ -15,6 +15,9 @@
  */
 package org.projectnessie.model.types;
 
+import static java.util.Objects.requireNonNull;
+
+import com.fasterxml.jackson.annotation.JsonTypeName;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -32,14 +35,6 @@
  */
 public final class ContentTypes {
 
-  /**
-   * An implementation of this interface is passed to {@link
-   * org.projectnessie.model.types.ContentTypeBundle}s.
-   */
-  public interface Registrar {
-    void register(String name, Class<? extends Content> type);
-  }
-
   /** Retrieve an array of all registered content types. */
   public static Content.Type[] all() {
     return Registry.all();
@@ -51,6 +46,48 @@ public static Content.Type forName(String name) {
     return Registry.forName(name);
   }
 
+  static final class RegistryHelper implements ContentTypeRegistry {
+
+    private final List<Content.Type> list = new ArrayList<>();
+    private final Map<String, Content.Type> names = new HashMap<>();
+
+    @Override
+    public void register(Class<? extends Content> type) {
+      requireNonNull(type, "Illegal content-type registration: type must not be null");
+
+      JsonTypeName jsonTypeName = type.getAnnotation(JsonTypeName.class);
+      if (jsonTypeName == null) {
+        throw new IllegalArgumentException(
+            String.format(
+                "Content-type registration: %s has no @JsonTypeName annotation", type.getName()));
+      }
+
+      String name = jsonTypeName.value();
+      if (name == null || name.trim().isEmpty() || !name.trim().equals(name)) {
+        throw new IllegalArgumentException(
+            String.format(
+                "Illegal content-type registration: illegal name '%s' for %s",
+                name, type.getName()));
+      }
+      Content.Type contentType = new ContentTypeImpl(name, type);
+
+      Content.Type ex = names.get(name);
+      if (ex != null) {
+        throw new IllegalStateException(
+            String.format(
+                "Duplicate content type registration for %s/%s, existing: %s/%s",
+                name, type.getName(), ex.name(), ex.type().getName()));
+      }
+
+      add(contentType);
+    }
+
+    void add(Content.Type unknownContentType) {
+      list.add(unknownContentType);
+      names.put(unknownContentType.name(), unknownContentType);
+    }
+  }
+
   /**
    * Internal class providing the actual registry. This is a separate class to implicitly use lazy
    * initialization.
@@ -61,40 +98,18 @@ private static final class Registry {
     private static final Map<String, Content.Type> byName;
 
     static {
-      List<Content.Type> list = new ArrayList<>();
-      Map<String, Content.Type> names = new HashMap<>();
+      RegistryHelper registryHelper = new RegistryHelper();
 
       // Add the "DEFAULT" type.
       Content.Type unknownContentType = new DefaultContentTypeImpl();
-      list.add(unknownContentType);
-      names.put(unknownContentType.name(), unknownContentType);
+      registryHelper.add(unknownContentType);
 
       for (ContentTypeBundle bundle : ServiceLoader.load(ContentTypeBundle.class)) {
-        bundle.register(
-            (name, type) -> {
-              if (name == null
-                  || name.trim().isEmpty()
-                  || !name.trim().equals(name)
-                  || type == null) {
-                throw new IllegalArgumentException(
-                    String.format(
-                        "Illegal content-type registration: name=%s, type=%s", name, type));
-              }
-              Content.Type contentType = new ContentTypeImpl(name, type);
-              Content.Type ex = names.get(name);
-              if (ex != null) {
-                throw new IllegalStateException(
-                    String.format(
-                        "Duplicate content type registration for %s/%s, existing: %s/%s",
-                        name, type, ex.name(), ex.type()));
-              }
-              list.add(contentType);
-              names.put(name, contentType);
-            });
+        bundle.register(registryHelper);
       }
 
-      byName = Collections.unmodifiableMap(names);
-      all = list.toArray(new Content.Type[0]);
+      byName = Collections.unmodifiableMap(registryHelper.names);
+      all = registryHelper.list.toArray(new Content.Type[0]);
     }
 
     private static Content.Type[] all() {
@@ -162,11 +177,6 @@ public int hashCode() {
       return 0;
     }
 
-    @Override
-    public boolean equals(Object obj) {
-      return obj == this;
-    }
-
     @Override
     public String toString() {
       return name();

api/model/src/main/java/org/projectnessie/model/types/MainContentTypeBundle.java

@@ -19,7 +19,6 @@
 import org.projectnessie.model.IcebergTable;
 import org.projectnessie.model.IcebergView;
 import org.projectnessie.model.Namespace;
-import org.projectnessie.model.types.ContentTypes.Registrar;
 
 /**
  * Provides the {@link org.projectnessie.model.Content.Type content types} for Iceberg table + view,
@@ -28,10 +27,10 @@
 public final class MainContentTypeBundle implements ContentTypeBundle {
 
   @Override
-  public void register(Registrar registrar) {
-    registrar.register("ICEBERG_TABLE", IcebergTable.class);
-    registrar.register("DELTA_LAKE_TABLE", DeltaLakeTable.class);
-    registrar.register("ICEBERG_VIEW", IcebergView.class);
-    registrar.register("NAMESPACE", Namespace.class);
+  public void register(ContentTypeRegistry contentTypeRegistry) {
+    contentTypeRegistry.register(IcebergTable.class);
+    contentTypeRegistry.register(DeltaLakeTable.class);
+    contentTypeRegistry.register(IcebergView.class);
+    contentTypeRegistry.register(Namespace.class);
   }
 }

api/model/src/test/java/org/projectnessie/model/types/CustomTestContent.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2023 Dremio
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.projectnessie.model.types;
+
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+import org.immutables.value.Value;
+import org.projectnessie.model.Content;
+
+@Value.Immutable
+@JsonSerialize(as = ImmutableCustomTestContent.class)
+@JsonDeserialize(as = ImmutableCustomTestContent.class)
+@JsonTypeName(CustomTestContent.TYPE)
+public abstract class CustomTestContent extends Content {
+  static final String TYPE = "TEST_CUSTOM_CONTENT_TYPE";
+
+  public abstract long getSomeLong();
+
+  public abstract String getSomeString();
+
+  @Override
+  public Type getType() {
+    return ContentTypes.forName(TYPE);
+  }
+}

api/model/src/test/java/org/projectnessie/model/types/CustomTestContentTypeBundle.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2023 Dremio
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.projectnessie.model.types;
+
+public class CustomTestContentTypeBundle implements ContentTypeBundle {
+
+  @Override
+  public void register(ContentTypeRegistry contentTypeRegistry) {
+    contentTypeRegistry.register(CustomTestContent.class);
+  }
+}

api/model/src/test/java/org/projectnessie/model/types/TestCustomContentType.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2023 Dremio
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.projectnessie.model.types;
+
+import static org.projectnessie.model.CommitMeta.fromMessage;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.assertj.core.api.SoftAssertions;
+import org.assertj.core.api.junit.jupiter.InjectSoftAssertions;
+import org.assertj.core.api.junit.jupiter.SoftAssertionsExtension;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.projectnessie.model.Content;
+import org.projectnessie.model.ContentKey;
+import org.projectnessie.model.ImmutableOperations;
+import org.projectnessie.model.Operation;
+import org.projectnessie.model.Operations;
+
+@ExtendWith(SoftAssertionsExtension.class)
+public class TestCustomContentType {
+  static final ObjectMapper MAPPER = new ObjectMapper();
+
+  @InjectSoftAssertions protected SoftAssertions soft;
+
+  @Test
+  void directSerialization() throws Exception {
+    CustomTestContent testContent =
+        ImmutableCustomTestContent.builder().someLong(42L).someString("blah").build();
+
+    String json = MAPPER.writeValueAsString(testContent);
+
+    Content deserializedAsContent = MAPPER.readValue(json, Content.class);
+    CustomTestContent deserializedAsTestContent = MAPPER.readValue(json, CustomTestContent.class);
+
+    soft.assertThat(deserializedAsContent).isEqualTo(testContent);
+    soft.assertThat(deserializedAsTestContent).isEqualTo(testContent);
+  }
+
+  @Test
+  void customContentInOperation() throws Exception {
+    CustomTestContent testContent =
+        ImmutableCustomTestContent.builder().someLong(42L).someString("blah").build();
+
+    Operations operations =
+        ImmutableOperations.builder()
+            .commitMeta(fromMessage("foo"))
+            .addOperations(Operation.Put.of(ContentKey.of("key"), testContent))
+            .build();
+
+    String json = MAPPER.writeValueAsString(operations);
+
+    Operations deserializedOperations = MAPPER.readValue(json, Operations.class);
+
+    soft.assertThat(deserializedOperations).isEqualTo(operations);
+  }
+}