add serializeNull and serializeEmpty config options for Jsonb.Builder

Author: rbygrave

blackbox-test/src/main/java/org/example/customer/SomeAddressWrapper.java

@@ -1,7 +1,8 @@
 package org.example.customer;
 
 import io.avaje.jsonb.Json;
+import java.util.List;
 
 @Json
-public record SomeAddressWrapper (Long id, Address address) {
+public record SomeAddressWrapper (Long id, Address address, List<String> tags) {
 }

blackbox-test/src/test/java/org/example/customer/SomeAddressWrapperTest.java

@@ -5,6 +5,7 @@
 import org.junit.jupiter.api.Test;
 
 import java.io.StringWriter;
+import java.util.Collections;
 import java.util.List;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -17,10 +18,10 @@ class SomeAddressWrapperTest {
   void test_when_null() {
 
     var type = jsonb.type(SomeAddressWrapper.class);
-    String asJson = type.toJson(new SomeAddressWrapper(43L, null));
+    String asJson = type.toJson(new SomeAddressWrapper(43L, null, Collections.emptyList()));
     assertThat(asJson).isEqualTo("{\"id\":43}");
 
-    var myList = List.of( new SomeAddressWrapper(43L, null),  new SomeAddressWrapper(44L, null));
+    var myList = List.of( new SomeAddressWrapper(43L, null, Collections.emptyList()),  new SomeAddressWrapper(44L, null, Collections.emptyList()));
 
     String asJsonList = type.list().toJson(myList);
     assertThat(asJsonList).isEqualTo("[{\"id\":43},{\"id\":44}]");
@@ -35,8 +36,41 @@ void includeNull() {
     writer.serializeEmpty(true);
 
     var type = jsonb.type(SomeAddressWrapper.class);
-    type.toJson(writer, new SomeAddressWrapper(43L, null));
+    type.toJson(writer, new SomeAddressWrapper(43L, null, Collections.emptyList()));
     writer.close();
-    assertThat(sw.toString()).isEqualTo("{\"id\":43,\"address\":null}");
+    assertThat(sw.toString()).isEqualTo("{\"id\":43,\"address\":null,\"tags\":[]}");
+  }
+
+
+  @Test
+  void includeNull_viaJsonB() {
+
+    Jsonb jsonb = Jsonb.newBuilder().serializeNulls(true).build();
+
+    var type = jsonb.type(SomeAddressWrapper.class);
+    String asJson = type.toJson(new SomeAddressWrapper(43L, null, Collections.emptyList()));
+    assertThat(asJson).isEqualTo("{\"id\":43,\"address\":null}");
+  }
+
+
+  @Test
+  void includeEmpty_viaJsonB() {
+
+    Jsonb jsonb = Jsonb.newBuilder().serializeEmpty(true).build();
+
+    var type = jsonb.type(SomeAddressWrapper.class);
+    String asJson = type.toJson(new SomeAddressWrapper(43L, null, Collections.emptyList()));
+    assertThat(asJson).isEqualTo("{\"id\":43,\"tags\":[]}");
+  }
+
+
+  @Test
+  void includeNullAndEmpty_viaJsonB() {
+
+    Jsonb jsonb = Jsonb.newBuilder().serializeNulls(true).serializeEmpty(true).build();
+
+    var type = jsonb.type(SomeAddressWrapper.class);
+    String asJson = type.toJson(new SomeAddressWrapper(43L, null, Collections.emptyList()));
+    assertThat(asJson).isEqualTo("{\"id\":43,\"address\":null,\"tags\":[]}");
   }
 }

jsonb/src/main/java/io/avaje/jsonb/Jsonb.java

@@ -110,6 +110,20 @@ static Builder newBuilder() {
    */
   interface Builder {
 
+    /**
+     * Set to serialise null values or not.
+     * <p>
+     * Default is to not serialise nulls.
+     */
+    Builder serializeNulls(boolean serializeNulls);
+
+    /**
+     * Set to serialise empty collections or not.
+     * <p>
+     * Default is to not serialise empty collections.
+     */
+    Builder serializeEmpty(boolean serializeEmpty);
+
     /**
      * Set failOnUnknown to true such that an exception is thrown when unknown
      * properties are read in the json content.

jsonb/src/main/java/io/avaje/jsonb/core/DJsonb.java

@@ -25,9 +25,9 @@ class DJsonb implements Jsonb {
   private final Map<Type, DJsonType<?>> typeCache = new ConcurrentHashMap<>();
   private final ConcurrentHashMap<ViewKey,JsonView<?>> viewCache = new ConcurrentHashMap<>();
 
-  DJsonb(List<JsonAdapter.Factory> factories, boolean failOnUnknown, boolean mathAsString) {
+  DJsonb(List<JsonAdapter.Factory> factories, boolean serializeNulls, boolean serializeEmpty, boolean failOnUnknown, boolean mathAsString) {
     this.builder = new CoreAdapterBuilder(this, factories, mathAsString);
-    this.io = new JacksonAdapter(failOnUnknown); //TODO: Service load the ioAdapter implementation
+    this.io = new JacksonAdapter(serializeNulls, serializeEmpty, failOnUnknown); //TODO: Service load the ioAdapter implementation
   }
 
   @Override
@@ -159,6 +159,20 @@ static final class DBuilder implements Jsonb.Builder {
     private final List<JsonAdapter.Factory> factories = new ArrayList<>();
     private boolean failOnUnknown;
     private boolean mathTypesAsString;
+    private boolean serializeNulls;
+    private boolean serializeEmpty;
+
+    @Override
+    public Builder serializeNulls(boolean serializeNulls) {
+      this.serializeNulls = serializeNulls;
+      return this;
+    }
+
+    @Override
+    public Builder serializeEmpty(boolean serializeEmpty) {
+      this.serializeEmpty = serializeEmpty;
+      return this;
+    }
 
     @Override
     public Builder failOnUnknown(boolean failOnUnknown) {
@@ -204,7 +218,7 @@ private void registerComponents() {
     @Override
     public DJsonb build() {
       registerComponents();
-      return new DJsonb(factories, failOnUnknown, mathTypesAsString);
+      return new DJsonb(factories, serializeNulls, serializeEmpty, failOnUnknown, mathTypesAsString);
     }
 
     static <T> JsonAdapter.Factory newAdapterFactory(Type type, JsonAdapter<T> jsonAdapter) {

jsonb/src/main/java/io/avaje/jsonb/jackson/JacksonAdapter.java

@@ -16,9 +16,13 @@
 public class JacksonAdapter implements IOAdapter {
 
   private final JsonFactory jsonFactory;
+  private final boolean serializeNulls;
+  private final boolean serializeEmpty;
   private final boolean failOnUnknown;
 
-  public JacksonAdapter(boolean failOnUnknown) {
+  public JacksonAdapter(boolean serializeNulls, boolean serializeEmpty, boolean failOnUnknown) {
+    this.serializeNulls = serializeNulls;
+    this.serializeEmpty = serializeEmpty;
     this.failOnUnknown = failOnUnknown;
     this.jsonFactory = new JsonFactory();
   }
@@ -67,7 +71,7 @@ public JsonReader reader(InputStream inputStream) {
   @Override
   public JsonWriter writer(Writer writer) {
     try {
-      return new JacksonWriter(jsonFactory.createGenerator(writer));
+      return new JacksonWriter(jsonFactory.createGenerator(writer), serializeNulls, serializeEmpty);
     } catch (IOException e) {
       throw new JsonIoException(e);
     }
@@ -77,7 +81,7 @@ public JsonWriter writer(Writer writer) {
   @Override
   public JsonWriter writer(OutputStream outputStream) {
     try {
-      return new JacksonWriter(jsonFactory.createGenerator(outputStream));
+      return new JacksonWriter(jsonFactory.createGenerator(outputStream), serializeNulls, serializeEmpty);
     } catch (IOException e) {
       throw new JsonIoException(e);
     }

jsonb/src/main/java/io/avaje/jsonb/jackson/JacksonWriter.java

@@ -22,8 +22,10 @@ final class JacksonWriter implements JsonWriter {
   private boolean pushedNames;
   private int namePos = -1;
 
-  JacksonWriter(JsonGenerator generator) {
+  JacksonWriter(JsonGenerator generator, boolean serializeNulls, boolean serializeEmpty) {
     this.generator = generator;
+    this.serializeNulls = serializeNulls;
+    this.serializeEmpty = serializeEmpty;
   }
 
   @Override