Make config of todomodel serialization more flexible.

todolist/core/src/main/java/todolist/json/TodoPersistence.java

@@ -10,6 +10,9 @@ import java.io.Writer;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.EnumSet;
+import java.util.Set;
+
 import todolist.core.TodoModel;
 import todolist.json.internal.TodoModule;
 
@@ -19,19 +22,27 @@ import todolist.json.internal.TodoModule;
  */
 public class TodoPersistence {
 
+  public enum TodoModelParts {
+    SETTINGS, LISTS, LIST_CONTENTS
+  }
+
   private ObjectMapper mapper;
 
   public TodoPersistence() {
     mapper = createObjectMapper();
   }
 
-  public static SimpleModule createJacksonModule(boolean deep) {
-    return new TodoModule(deep);
+  public static SimpleModule createJacksonModule(Set<TodoModelParts> parts) {
+    return new TodoModule(parts);
   }
 
-  public static ObjectMapper createObjectMapper() {
+  public static ObjectMapper createObjectMapper(Set<TodoModelParts> parts) {
     return new ObjectMapper()
-      .registerModule(createJacksonModule(true));
+      .registerModule(createJacksonModule(parts));
+  }
+
+  public static ObjectMapper createObjectMapper() {
+    return createObjectMapper(EnumSet.allOf(TodoModelParts.class));
   }
 
   public TodoModel readTodoModel(Reader reader) throws IOException {

todolist/core/src/main/java/todolist/json/internal/TodoModelSerializer.java

@@ -4,19 +4,19 @@ import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.JsonSerializer;
 import com.fasterxml.jackson.databind.SerializerProvider;
 import java.io.IOException;
+import java.util.EnumSet;
+import java.util.Set;
+
 import todolist.core.AbstractTodoList;
 import todolist.core.TodoModel;
+import todolist.json.TodoPersistence.TodoModelParts;
 
 class TodoModelSerializer extends JsonSerializer<TodoModel> {
 
-  private final boolean deep;
-
-  public TodoModelSerializer(boolean deep) {
-    this.deep = deep;
-  }
+  private final Set<TodoModelParts> parts;
 
-  public TodoModelSerializer() {
-    this(true);
+  public TodoModelSerializer(Set<TodoModelParts> parts) {
+    this.parts = parts;
   }
 
   /*
@@ -27,23 +27,27 @@ class TodoModelSerializer extends JsonSerializer<TodoModel> {
   public void serialize(TodoModel model, JsonGenerator jsonGen, SerializerProvider
       serializerProvider) throws IOException {
     jsonGen.writeStartObject();
-    jsonGen.writeArrayFieldStart("lists");
-    for (AbstractTodoList list : model) {
-      if (deep) {
-        jsonGen.writeObject(list);
-      } else {
-        jsonGen.writeStartObject();
-        jsonGen.writeStringField("name", list.getName());
-        if (list.getDeadline() != null) {
-          jsonGen.writeStringField("deadline", list.getDeadline().toString());
+    if (parts.contains(TodoModelParts.LIST_CONTENTS) || parts.contains(TodoModelParts.LISTS)) {
+      jsonGen.writeArrayFieldStart("lists");
+      for (AbstractTodoList list : model) {
+        if (parts.contains(TodoModelParts.LIST_CONTENTS)) {
+          jsonGen.writeObject(list);
+        } else if (parts.contains(TodoModelParts.LISTS)) {
+          jsonGen.writeStartObject();
+          jsonGen.writeStringField("name", list.getName());
+          if (list.getDeadline() != null) {
+            jsonGen.writeStringField("deadline", list.getDeadline().toString());
+          }
+          // no items!
+          jsonGen.writeEndObject();
         }
-        // no items!
-        jsonGen.writeEndObject();
       }
+      jsonGen.writeEndArray();
+    }
+    if (parts.contains(TodoModelParts.SETTINGS)) {
+      jsonGen.writeFieldName("settings");
+      jsonGen.writeObject(model.getSettings());
     }
-    jsonGen.writeEndArray();
-    jsonGen.writeFieldName("settings");
-    jsonGen.writeObject(model.getSettings());
     jsonGen.writeEndObject();
   }
 }
\ No newline at end of file

todolist/core/src/main/java/todolist/json/internal/TodoModule.java

 package todolist.json.internal;
 
+import java.util.EnumSet;
+import java.util.Set;
+
 import com.fasterxml.jackson.core.Version;
 import com.fasterxml.jackson.databind.module.SimpleModule;
 import todolist.core.AbstractTodoList;
 import todolist.core.TodoItem;
 import todolist.core.TodoModel;
 import todolist.core.TodoSettings;
+import todolist.json.TodoPersistence.TodoModelParts;
 
 /**
  * A Jackson module for configuring JSON serialization of TodoModel instances.
@@ -18,7 +22,7 @@ public class TodoModule extends SimpleModule {
   /**
    * Initializes this TodoModule with appropriate serializers and deserializers.
    */
-  public TodoModule(boolean deepTodoModelSerializer) {
+  public TodoModule(Set<TodoModelParts> parts) {
     super(NAME, Version.unknownVersion());
     addSerializer(TodoItem.class, new TodoItemSerializer());
     addDeserializer(TodoItem.class, new TodoItemDeserializer());
@@ -26,7 +30,7 @@ public class TodoModule extends SimpleModule {
     addSerializer(AbstractTodoList.class, new TodoListSerializer());
     addDeserializer(AbstractTodoList.class, new TodoListDeserializer());
 
-    addSerializer(TodoModel.class, new TodoModelSerializer(deepTodoModelSerializer));
+    addSerializer(TodoModel.class, new TodoModelSerializer(parts));
     addDeserializer(TodoModel.class, new TodoModelDeserializer());
 
     addSerializer(TodoSettings.class, new TodoSettingsSerializer());
@@ -34,6 +38,6 @@ public class TodoModule extends SimpleModule {
   }
 
   public TodoModule() {
-    this(true);
+    this(EnumSet.allOf(TodoModelParts.class));
   }
 }

todolist/rest/src/main/java/todolist/restapi/TodoListResource.java

@@ -3,6 +3,7 @@ package todolist.restapi;
 import jakarta.ws.rs.Consumes;
 import jakarta.ws.rs.DELETE;
 import jakarta.ws.rs.GET;
+import jakarta.ws.rs.NotFoundException;
 import jakarta.ws.rs.POST;
 import jakarta.ws.rs.PUT;
 import jakarta.ws.rs.Path;
@@ -51,9 +52,11 @@ public class TodoListResource {
     this.todoList = todoList;
   }
 
+  // throw an exception in case of missing todolist
+  // hopefully this will give an appropriate http response code
   private void checkTodoList() {
     if (this.todoList == null) {
-      throw new IllegalArgumentException("No TodoList named \"" + name + "\"");
+      throw new NotFoundException("No TodoList named \"" + name + "\"");
     }
   }
 
@@ -74,7 +77,7 @@ public class TodoListResource {
       try {
         todoPersistence.saveTodoModel(todoModel);
       } catch (IllegalStateException | IOException e) {
-        System.err.println("Couldn't auto-save TodoModel: " + e);
+        LOG.error("Couldn't auto-save TodoModel: ", e);
       }
     }
   }

todolist/rest/src/main/java/todolist/restserver/TodoConfig.java

@@ -8,6 +8,8 @@ import java.nio.charset.StandardCharsets;
 import org.glassfish.hk2.utilities.binding.AbstractBinder;
 import org.glassfish.jersey.jackson.JacksonFeature;
 import org.glassfish.jersey.server.ResourceConfig;
+
+import todolist.core.TodoItem;
 import todolist.core.TodoList;
 import todolist.core.TodoModel;
 import todolist.json.TodoPersistence;
@@ -71,7 +73,9 @@ public class TodoConfig extends ResourceConfig {
       }
     }
     TodoModel todoModel = new TodoModel();
-    todoModel.addTodoList(new TodoList("todo1"));
+    TodoList todoList1 = new TodoList("todo1");
+    todoList1.addTodoItem(new TodoItem());
+    todoModel.addTodoList(todoList1);
     todoModel.addTodoList(new TodoList("todo2"));
     return todoModel;
   }

todolist/rest/src/main/java/todolist/restserver/TodoModuleObjectMapperProvider.java

 package todolist.restserver;
 
+import java.util.EnumSet;
+
 import com.fasterxml.jackson.databind.ObjectMapper;
 import jakarta.ws.rs.Consumes;
 import jakarta.ws.rs.Produces;
@@ -7,6 +9,7 @@ import jakarta.ws.rs.core.MediaType;
 import jakarta.ws.rs.ext.ContextResolver;
 import jakarta.ws.rs.ext.Provider;
 import todolist.json.TodoPersistence;
+import todolist.json.TodoPersistence.TodoModelParts;
 
 /**
  * Provides the Jackson module used for JSON serialization.
@@ -19,7 +22,10 @@ public class TodoModuleObjectMapperProvider implements ContextResolver<ObjectMap
   private final ObjectMapper objectMapper;
 
   public TodoModuleObjectMapperProvider() {
-    objectMapper = TodoPersistence.createObjectMapper();
+    // Uuse variant which only serializes list properties as part of TodoModel objects, and
+    // not the contents, nor settings
+    // The contents or settings are serialized as part of TodoList and TodoSettings objects
+    objectMapper = TodoPersistence.createObjectMapper(EnumSet.of(TodoModelParts.LISTS));
   }
 
   @Override

todolist/rest/src/test/java/todolist/restserver/TodoServiceTest.java

@@ -17,6 +17,7 @@ import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import todolist.core.AbstractTodoList;
+import todolist.core.TodoList;
 import todolist.core.TodoModel;
 import todolist.restapi.TodoModelService;
 
@@ -84,6 +85,8 @@ public class TodoServiceTest extends JerseyTest {
     try {
       AbstractTodoList todoList = objectMapper.readValue(getResponse.readEntity(String.class), AbstractTodoList.class);
       assertEquals("todo1", todoList.getName());
+      assertTrue(todoList instanceof TodoList);
+      assertTrue(((TodoList) todoList).iterator().hasNext());
     } catch (JsonProcessingException e) {
       fail(e.getMessage());
     }

todolist/springboot/restserver/src/main/java/todolist/springboot/restserver/TodoModelApplication.java

 package todolist.springboot.restserver;
 
+import java.util.EnumSet;
+
 import com.fasterxml.jackson.databind.Module;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.Bean;
 import todolist.json.TodoPersistence;
+import todolist.json.TodoPersistence.TodoModelParts;
 
 /**
  * The Spring application.
@@ -14,7 +17,7 @@ public class TodoModelApplication {
 
   @Bean
   public Module objectMapperModule() {
-    return TodoPersistence.createJacksonModule(false);
+    return TodoPersistence.createJacksonModule(EnumSet.of(TodoModelParts.LISTS));
   }
 
   public static void main(String[] args) {

todolist/springboot/restserver/src/main/java/todolist/springboot/restserver/TodoModelService.java

@@ -6,6 +6,8 @@ import java.io.Reader;
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
 import org.springframework.stereotype.Service;
+
+import todolist.core.TodoItem;
 import todolist.core.TodoList;
 import todolist.core.TodoModel;
 import todolist.json.TodoPersistence;
@@ -56,7 +58,9 @@ public class TodoModelService {
       }
     }
     TodoModel todoModel = new TodoModel();
-    todoModel.addTodoList(new TodoList("todo1"));
+    TodoList todoList1 = new TodoList("todo1");
+    todoList1.addTodoItem(new TodoItem());
+    todoModel.addTodoList(todoList1);
     todoModel.addTodoList(new TodoList("todo2"));
     return todoModel;
   }