DTO Mapping

docs/definitions/README.md

@@ -11,3 +11,4 @@ This chapter explains the various options for defining class models.
 * [Inheritance](7-inheritance.md)
 * [Methods](8-methods.md)
 * [EMF and Ecore files](9-emf-ecore.md)
+* [DTOs](10-dtos.md)

src/main/java/org/fulib/builder/ReflectiveClassBuilder.java

@@ -6,22 +6,43 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
+import java.util.Arrays;
 import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.function.Predicate;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
-import static org.fulib.builder.Type.MANY;
-import static org.fulib.builder.Type.ONE;
+import static org.fulib.builder.Type.*;
 
 class ReflectiveClassBuilder
 {
    private static final String ID_PATTERN = "\\p{javaJavaIdentifierStart}\\p{javaJavaIdentifierPart}*";
    private static final Pattern CLASS_PATTERN = Pattern.compile(ID_PATTERN + "(?:\\." + ID_PATTERN + ")*");
+   private final ClassModelManager manager;
 
-   static Clazz load(Class<?> classDef, ClassModelManager manager)
+   ReflectiveClassBuilder(ClassModelManager classModelManager)
+   {
+      this.manager = classModelManager;
+   }
+
+   static Clazz load(Class<?> classDef, ClassModelManager classModelManager)
+   {
+      return new ReflectiveClassBuilder(classModelManager).load(classDef);
+   }
+
+   Clazz load(Class<?> classDef)
    {
       final Clazz clazz = manager.haveClass(classDef.getSimpleName());
 
+      final DTO dto = classDef.getAnnotation(DTO.class);
+      if (dto != null)
+      {
+         loadDto(dto, clazz);
+      }
+
       final Class<?> superClass = classDef.getSuperclass();
       if (superClass != null && superClass != Object.class)
       {
@@ -32,13 +53,29 @@ static Clazz load(Class<?> classDef, ClassModelManager manager)
 
       for (final Field field : classDef.getDeclaredFields())
       {
-         loadField(field, clazz, manager);
+         loadField(field, clazz, false);
       }
 
       return clazz;
    }
 
-   private static void loadField(Field field, Clazz clazz, ClassModelManager manager)
+   private void loadDto(DTO dto, Clazz clazz)
+   {
+      final Class<?> model = dto.model();
+      final Set<String> include = new HashSet<>(Arrays.asList(dto.pick()));
+      final Set<String> exclude = new HashSet<>(Arrays.asList(dto.omit()));
+
+      for (final Field field : model.getDeclaredFields())
+      {
+         final String name = field.getName();
+         if ((include.isEmpty() || include.contains(name)) && !exclude.contains(name))
+         {
+            loadField(field, clazz, true);
+         }
+      }
+   }
+
+   private void loadField(Field field, Clazz clazz, boolean dto)
    {
       if (field.isSynthetic())
       {
@@ -48,33 +85,40 @@ private static void loadField(Field field, Clazz clazz, ClassModelManager manage
       final Link link = field.getAnnotation(Link.class);
       if (link == null)
       {
-         loadAttribute(field, clazz, manager);
+         loadAttribute(field, clazz, false);
+      }
+      else if (dto)
+      {
+         loadAttribute(field, clazz, true);
       }
       else
       {
-         loadAssoc(field, link, clazz, manager);
+         loadAssoc(field, link, clazz);
       }
    }
 
-   private static void loadAttribute(Field field, Clazz clazz, ClassModelManager manager)
+   private void loadAttribute(Field field, Clazz clazz, boolean dto)
    {
       final String name = field.getName();
       final CollectionType collectionType = getCollectionType(field.getType());
-      final String type = getType(field, collectionType);
+      final String type = dto ? STRING : getType(field, collectionType);
 
       final Attribute attribute = manager.haveAttribute(clazz, name, type);
       attribute.setCollectionType(collectionType);
       attribute.setDescription(getDescription(field));
       attribute.setSince(getSince(field));
 
-      final InitialValue initialValue = field.getAnnotation(InitialValue.class);
-      if (initialValue != null)
+      if (!dto)
       {
-         attribute.setInitialization(initialValue.value());
+         final InitialValue initialValue = field.getAnnotation(InitialValue.class);
+         if (initialValue != null)
+         {
+            attribute.setInitialization(initialValue.value());
+         }
       }
    }
 
-   private static String getType(Field field, CollectionType collectionType)
+   private String getType(Field field, CollectionType collectionType)
    {
       final org.fulib.builder.reflect.Type type = field.getAnnotation(org.fulib.builder.reflect.Type.class);
       if (type != null)
@@ -95,11 +139,11 @@ private static String getType(Field field, CollectionType collectionType)
       }
 
       throw new InvalidClassModelException(
-         String.format("%s.%s: cannot determine element type of %s", declaringClass.getSimpleName(),
-                       field.getName(), field.getType().getSimpleName()));
+         String.format("%s.%s: cannot determine element type of %s", declaringClass.getSimpleName(), field.getName(),
+                       field.getType().getSimpleName()));
    }
 
-   private static String toSource(Class<?> base, Type type)
+   private String toSource(Class<?> base, Type type)
    {
       final String input = type.getTypeName();
       final Matcher matcher = CLASS_PATTERN.matcher(input);
@@ -116,7 +160,7 @@ private static String toSource(Class<?> base, Type type)
       return sb.toString();
    }
 
-   private static void toSource(Class<?> base, String className, StringBuilder out)
+   private void toSource(Class<?> base, String className, StringBuilder out)
    {
       switch (className)
       {
@@ -146,7 +190,8 @@ else if (resolvedPackage == base.getPackage())
          {
             out.append(resolved.getSimpleName());
          }
-         else if (resolved.getEnclosingClass() != null && ClassModelDecorator.class.isAssignableFrom(resolved.getEnclosingClass()))
+         else if (resolved.getEnclosingClass() != null && ClassModelDecorator.class.isAssignableFrom(
+            resolved.getEnclosingClass()))
          {
             // resolved is nested class within another GenModel
             out
@@ -167,7 +212,7 @@ else if (resolved.getEnclosingClass() != null && ClassModelDecorator.class.isAss
       }
    }
 
-   private static CollectionType getCollectionType(Class<?> type)
+   private CollectionType getCollectionType(Class<?> type)
    {
       if (!Collection.class.isAssignableFrom(type))
       {
@@ -184,7 +229,7 @@ private static CollectionType getCollectionType(Class<?> type)
       return CollectionType.of(collectionType);
    }
 
-   private static void loadAssoc(Field field, Link link, Clazz clazz, ClassModelManager manager)
+   private void loadAssoc(Field field, Link link, Clazz clazz)
    {
       final Class<?> owner = field.getDeclaringClass();
       final String name = field.getName();
@@ -214,7 +259,7 @@ private static void loadAssoc(Field field, Link link, Clazz clazz, ClassModelMan
       role.setSince(getSince(field));
    }
 
-   private static void validateTargetClass(Class<?> owner, String name, Class<?> other)
+   private void validateTargetClass(Class<?> owner, String name, Class<?> other)
    {
       if (owner.getPackage() != other.getPackage())
       {
@@ -225,7 +270,7 @@ private static void validateTargetClass(Class<?> owner, String name, Class<?> ot
       }
    }
 
-   private static void validateLinkTarget(Class<?> owner, String name, String otherName, Class<?> other)
+   private void validateLinkTarget(Class<?> owner, String name, String otherName, Class<?> other)
    {
       final Field targetField;
       try
@@ -265,7 +310,7 @@ private static void validateLinkTarget(Class<?> owner, String name, String other
       }
    }
 
-   private static Class<?> getOther(Field field, CollectionType collectionType)
+   private Class<?> getOther(Field field, CollectionType collectionType)
    {
       final org.fulib.builder.reflect.Type type = field.getAnnotation(org.fulib.builder.reflect.Type.class);
       if (type != null)
@@ -293,7 +338,7 @@ private static Class<?> getOther(Field field, CollectionType collectionType)
                        field.getName(), field.getType().getSimpleName()));
    }
 
-   private static Class<?> getSiblingClass(Field field, String simpleSiblingName)
+   private Class<?> getSiblingClass(Field field, String simpleSiblingName)
    {
       final Class<?> declaringClass = field.getDeclaringClass();
       final String name = declaringClass.getName();
@@ -312,13 +357,13 @@ private static Class<?> getSiblingClass(Field field, String simpleSiblingName)
       }
    }
 
-   private static String getDescription(Field field)
+   private String getDescription(Field field)
    {
       final Description annotation = field.getAnnotation(Description.class);
       return annotation != null ? annotation.value() : null;
    }
 
-   private static String getSince(Field field)
+   private String getSince(Field field)
    {
       final Since annotation = field.getAnnotation(Since.class);
       return annotation != null ? annotation.value() : null;

src/main/java/org/fulib/builder/reflect/DTO.java

@@ -0,0 +1,32 @@
+package org.fulib.builder.reflect;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Allows creating Data Transfer Object (DTO) classes by copying attributes from a model class.
+ * Associations are automatically converted to String attributes meant for holding the ID of the link target.
+ *
+ * @since 1.6
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface DTO
+{
+   /**
+    * @return the model class to copy attributes from
+    */
+   Class<?> model();
+
+   /**
+    * @return the names of fields that should be included. Ignored if empty.
+    */
+   String[] pick() default {};
+
+   /**
+    * @return the names of fields that should be excluded
+    */
+   String[] omit() default {};
+}

src/test/java/org/fulib/builder/ReflectiveClassBuilderTest.java

@@ -317,4 +317,61 @@ public void invalidLinkClassPackage()
       assertThat(ex.getMessage(), equalTo(
          "InvalidLinkClassPackage.student: invalid link: target class Student (org.fulib.builder.model) must be in the same package (org.fulib.builder)"));
    }
+
+   @DTO(model = Person.class)
+   class PersonDto
+   {}
+
+   @Test
+   public void dto()
+   {
+      final ClassModelManager cmm = new ClassModelManager();
+      final Clazz personDto = ReflectiveClassBuilder.load(PersonDto.class, cmm);
+
+      assertThat(personDto.getRole("links"), nullValue());
+
+      final Attribute name = personDto.getAttribute("name");
+      assertThat(name.getType(), is(Type.STRING));
+
+      final Attribute friends = personDto.getAttribute("friends");
+      assertThat(friends.getType(), is(Type.STRING));
+      assertThat(friends.getCollectionType(), is(CollectionType.ArrayList));
+
+      final Attribute dateOfBirth = personDto.getAttribute("dateOfBirth");
+      assertThat(dateOfBirth.getType(), is("import(java.util.Date)"));
+   }
+
+   @DTO(model = Person.class, pick = { "friends" })
+   class PersonLinksDto
+   {}
+
+   @DTO(model = Person.class, omit = { "friends" })
+   class PersonAttributesDto
+   {}
+
+   @Test
+   public void dtoPickOmit()
+   {
+      final ClassModelManager cmm = new ClassModelManager();
+      final Clazz personLinksDto = ReflectiveClassBuilder.load(PersonLinksDto.class, cmm);
+
+      assertThat(personLinksDto.getAttribute("name"), nullValue());
+      assertThat(personLinksDto.getAttribute("dateOfBirth"), nullValue());
+      assertThat(personLinksDto.getRole("links"), nullValue());
+
+      final Attribute friends = personLinksDto.getAttribute("friends");
+      assertThat(friends.getType(), is(Type.STRING));
+      assertThat(friends.getCollectionType(), is(CollectionType.ArrayList));
+
+      final Clazz personAttributesDto = ReflectiveClassBuilder.load(PersonAttributesDto.class, cmm);
+
+      final Attribute name = personAttributesDto.getAttribute("name");
+      assertThat(name.getType(), is(Type.STRING));
+
+      final Attribute dateOfBirth = personAttributesDto.getAttribute("dateOfBirth");
+      assertThat(dateOfBirth.getType(), is("import(java.util.Date)"));
+
+      assertThat(personAttributesDto.getAttribute("links"), nullValue());
+      assertThat(personAttributesDto.getRole("links"), nullValue());
+   }
 }

test/src/gen/java/org/fulib/docs/GenModel.java

@@ -3,15 +3,12 @@
 import it.unimi.dsi.fastutil.ints.IntArrayList;
 import org.fulib.builder.ClassModelDecorator;
 import org.fulib.builder.ClassModelManager;
-import org.fulib.builder.reflect.Type;
-import org.fulib.builder.reflect.Description;
-import org.fulib.builder.reflect.InitialValue;
-import org.fulib.builder.reflect.Link;
-import org.fulib.builder.reflect.Since;
+import org.fulib.builder.reflect.*;
 
 import java.util.ArrayList;
 import java.util.List;
 
+@SuppressWarnings({ "unused", "InnerClassMayBeStatic" })
 public class GenModel implements ClassModelDecorator
 {
    // start_code_fragment: docs.GenModel.Person

test/src/gen/java/org/fulib/docs/dtos/dto/GenDtos.java

@@ -0,0 +1,28 @@
+package org.fulib.docs.dtos.dto;
+
+import org.fulib.builder.ClassModelDecorator;
+import org.fulib.builder.ClassModelManager;
+import org.fulib.builder.Type;
+import org.fulib.builder.reflect.DTO;
+import org.fulib.docs.dtos.model.GenModel;
+
+// start_code_fragment: docs.dtos.GenDtos
+public class GenDtos implements ClassModelDecorator
+{
+   @DTO(model = GenModel.User.class, omit = { "id" })
+   class UserDto
+   {}
+
+   @DTO(model = GenModel.Address.class, pick = { "city", "street" })
+   class AddressDto
+   {}
+
+   @Override
+   public void decorate(ClassModelManager m)
+   {
+      // This omits PropertyChangeListeners etc. from the generated code
+      m.getClassModel().setDefaultPropertyStyle(Type.POJO);
+      m.haveNestedClasses(GenDtos.class);
+   }
+}
+// end_code_fragment: