Add support to configure adding jackson @JsonPOJOBuilder annotations to generated builders

Author: maff

options.md

@@ -54,6 +54,12 @@ The names used for generated methods, classes, etc. can be changed via the follo
 | `@RecordBuilder.Options(fileIndent = "    ")`                    | Return the file indent to use.                                                                                                                           |
 | `@RecordBuilder.Options(prefixEnclosingClassNames = true/false)` | If the record is declared inside another class, the outer class's name will be prefixed to the builder name if this returns true. The default is `true`. |
 
+## Jackson Support
+
+| option                                                       | details                                                                                                                                                                                                                                                                                                                      |
+|--------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `@RecordBuilder.Options(addJacksonAnnotations = true/false)` | If true, builders will be annotated with `@JsonPOJOBuilder` Jackson annotations which can be used in combination with `@JsonDeserialize(builder = ...)`. See [TestJacksonAnnotations](./record-builder-test/src/test/java/io/soabase/recordbuilder/test/TestJacksonAnnotations.java) for an example. The default is `false`. |
+
 ## Miscellaneous
 
 | option                                                               | details                                                                                                                                                          |

pom.xml

@@ -64,6 +64,7 @@
         <hibernate-validator-version>6.2.0.Final</hibernate-validator-version>
         <jakarta-validation-api-version>3.1.0</jakarta-validation-api-version>
         <javax-el-version>3.0.1-b09</javax-el-version>
+        <jackson-version>2.19.0</jackson-version>
         <central-publishing-maven-plugin-version>0.7.0</central-publishing-maven-plugin-version>
     </properties>
 
@@ -165,6 +166,12 @@
                 <version>${hibernate-validator-version}</version>
             </dependency>
 
+            <dependency>
+                <groupId>com.fasterxml.jackson.core</groupId>
+                <artifactId>jackson-databind</artifactId>
+                <version>${jackson-version}</version>
+            </dependency>
+
             <dependency>
                 <groupId>org.glassfish</groupId>
                 <artifactId>javax.el</artifactId>

record-builder-core/src/main/java/io/soabase/recordbuilder/core/RecordBuilder.java

@@ -353,6 +353,8 @@
          * @see #nullablePattern
          */
         boolean defaultNotNull() default false;
+
+        boolean addJacksonAnnotations() default false;
     }
 
     @Retention(RetentionPolicy.CLASS)

record-builder-processor/src/main/java/io/soabase/recordbuilder/processor/InternalRecordBuilderProcessor.java

@@ -86,6 +86,8 @@ class InternalRecordBuilderProcessor {
             builder.addAnnotation(recordBuilderGeneratedAnnotation);
         }
 
+        addJacksonAnnotations();
+
         if (!validateMethodNameConflicts(processingEnv, recordFacade.element())) {
             builderType = Optional.empty();
             return;
@@ -196,6 +198,18 @@ private void addVisibility(boolean builderIsInRecordPackage, Set<Modifier> modif
         }
     }
 
+    private void addJacksonAnnotations() {
+        if (!metaData.addJacksonAnnotations()) {
+            return;
+        }
+
+        final var annotationSpec = AnnotationSpec
+                .builder(ClassName.get("com.fasterxml.jackson.databind.annotation", "JsonPOJOBuilder"))
+                .addMember("withPrefix", "$S", metaData.setterPrefix()).build();
+
+        builder.addAnnotation(annotationSpec);
+    }
+
     private void addOnceOnlySupport() {
         if (recordComponents.isEmpty()) {
             return;

record-builder-test/pom.xml

@@ -60,6 +60,11 @@
             <scope>provided</scope>
         </dependency>
 
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+        </dependency>
+
         <dependency>
             <groupId>org.glassfish</groupId>
             <artifactId>javax.el</artifactId>

record-builder-test/src/main/java/io/soabase/recordbuilder/test/JacksonAnnotated.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2019 The original author or authors
+ *
+ * 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 io.soabase.recordbuilder.test;
+
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import io.soabase.recordbuilder.core.RecordBuilder;
+
+import java.util.Map;
+
+public interface JacksonAnnotated {
+    String name();
+
+    String type();
+
+    Map<String, Object> properties();
+
+    @RecordBuilder
+    @RecordBuilder.Options(addJacksonAnnotations = true, useImmutableCollections = true, prefixEnclosingClassNames = false)
+    @JsonDeserialize(builder = JacksonAnnotatedRecordBuilder.class)
+    record JacksonAnnotatedRecord(String name, @RecordBuilder.Initializer("DEFAULT_TYPE") String type,
+            Map<String, Object> properties) implements JacksonAnnotated {
+        public static final String DEFAULT_TYPE = "dummy";
+    }
+
+    @RecordBuilder
+    @RecordBuilder.Options(addJacksonAnnotations = true, useImmutableCollections = true, prefixEnclosingClassNames = false, setterPrefix = "set")
+    @JsonDeserialize(builder = JacksonAnnotatedRecordCustomSetterPrefixBuilder.class)
+    record JacksonAnnotatedRecordCustomSetterPrefix(String name, @RecordBuilder.Initializer("DEFAULT_TYPE") String type,
+            Map<String, Object> properties) implements JacksonAnnotated {
+        public static final String DEFAULT_TYPE = "dummy";
+    }
+}

record-builder-test/src/test/java/io/soabase/recordbuilder/test/TestJacksonAnnotations.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2019 The original author or authors
+ *
+ * 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 io.soabase.recordbuilder.test;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.annotation.JsonPOJOBuilder;
+import io.soabase.recordbuilder.test.JacksonAnnotated.JacksonAnnotatedRecord;
+import io.soabase.recordbuilder.test.JacksonAnnotated.JacksonAnnotatedRecordCustomSetterPrefix;
+import org.assertj.core.api.InstanceOfAssertFactories;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import java.util.Arrays;
+import java.util.stream.Stream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.params.provider.Arguments.arguments;
+
+class TestJacksonAnnotations {
+    private final ObjectMapper objectMapper = new ObjectMapper();
+
+    @ParameterizedTest
+    @MethodSource("recordBuilders")
+    void addsJsonPOJOBuilderAnnotation(Class<? extends JacksonAnnotated> type, String expectedPrefix) {
+        final var annotations = Arrays.stream(type.getAnnotations()).toList();
+        assertThat(annotations).filteredOn(annotation -> annotation.annotationType().equals(JsonPOJOBuilder.class))
+                .hasSize(1).first().asInstanceOf(InstanceOfAssertFactories.type(JsonPOJOBuilder.class))
+                .satisfies(annotation -> {
+                    assertThat(annotation.withPrefix()).isEqualTo(expectedPrefix);
+                });
+    }
+
+    static Stream<Arguments> recordBuilders() {
+        return Stream.of(arguments(JacksonAnnotatedRecordBuilder.class, ""),
+                arguments(JacksonAnnotatedRecordCustomSetterPrefixBuilder.class, "set"));
+    }
+
+    @ParameterizedTest
+    @ValueSource(classes = { JacksonAnnotatedRecord.class, JacksonAnnotatedRecordCustomSetterPrefix.class })
+    void deserializingModelInvokesBuilder(Class<? extends JacksonAnnotated> type) throws JsonProcessingException {
+        final var json = """
+                {
+                  "name" : "test"
+                }
+                """;
+
+        final var model = objectMapper.readValue(json, type);
+        assertThat(model.name()).isEqualTo("test");
+        assertThat(model.type()).isEqualTo("dummy"); // default value
+        assertThat(model.properties()).isNotNull().isEmpty(); // non-null initialized immutable collection
+    }
+}