Allow using @Translatable on objects

Up until now, the `@Translatable` annotation
only worked on Strings and Enums.
To be able to also specify more complex objects as
translatable, the annotation is extended by an
optional `toStringMethod` which is used to retrieve
a string value to translate for those objects.

build.gradle

@@ -8,7 +8,7 @@ plugins {
 }
 
 group 'com.docutools'
-version = '1.5.6-beta.1'
+version = '1.5.7-alpha.1'
 
 sourceCompatibility = JavaVersion.VERSION_17
 targetCompatibility = JavaVersion.VERSION_17

src/main/java/com/docutools/jocument/annotations/Translatable.java

@@ -5,4 +5,10 @@
 
 @Retention(RetentionPolicy.RUNTIME)
 public @interface Translatable {
+  /**
+   * Specify the method which should be applied to retrieve a (translatable) string from the annotated object.
+   *
+   * @return The name of the method to use to retrieve the string which should be translated from objects
+   */
+  String toStringMethod() default "toString";
 }

src/main/java/com/docutools/jocument/impl/ReflectionResolver.java

@@ -392,6 +392,8 @@ private Optional<PlaceholderData> resolveSimplePlaceholder(Object property, Stri
       } else {
         return Optional.of(new ScalarPlaceholderData<>(enumProperty));
       }
+    } else if (isFieldAnnotatedWith(bean.getClass(), placeholderName, Translatable.class)) {
+      return getObjectTranslation(placeholderName, locale, options);
     } else if (property instanceof Enum || property instanceof String || ReflectionUtils.isWrapperType(property.getClass())) {
       return Optional.of(new ScalarPlaceholderData<>(property));
     } else if (property instanceof Temporal temporal) {
@@ -404,6 +406,23 @@ private Optional<PlaceholderData> resolveSimplePlaceholder(Object property, Stri
     }
   }
 
+  private Optional<PlaceholderData> getObjectTranslation(String placeholderName, Locale locale, GenerationOptions options) {
+    var translatable = ReflectionUtils.findFieldAnnotation(bean.getClass(), placeholderName, Translatable.class);
+    if (translatable.isPresent()) {
+      try {
+        Optional<Object> beanProperty = getBeanProperty(placeholderName);
+        if (beanProperty.isPresent()) {
+          String toStringMethod = translatable.get().toStringMethod();
+          String propertyString = (String) beanProperty.get().getClass().getMethod(toStringMethod).invoke(beanProperty.get());
+          return Optional.of(new ScalarPlaceholderData<>(options.translate(propertyString, locale).orElse(propertyString)));
+        }
+      } catch (InvocationTargetException | IllegalAccessException | NoSuchMethodException e) {
+        logger.error("Could not invoke custom 'toString' method", e);
+      }
+    }
+    return Optional.empty();
+  }
+
   private Optional<Object> getBeanProperty(String placeholderName) throws InvocationTargetException, IllegalAccessException, NoSuchMethodException {
     var ignoreCasePlaceholder = placeholderName.toLowerCase();
     if (SELF_REFERENCE.equals(placeholderName)) {

src/test/java/com/docutools/jocument/ReflectionResolvingTests.java

@@ -5,7 +5,9 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
 
+import com.docutools.jocument.impl.CustomPlaceholderRegistryImpl;
 import com.docutools.jocument.impl.ReflectionResolver;
+import com.docutools.jocument.sample.model.Person;
 import com.docutools.jocument.sample.model.SampleModelData;
 import com.docutools.jocument.sample.model.Ship;
 import com.docutools.jocument.sample.model.Uniform;
@@ -253,4 +255,23 @@ void shouldResolveWrongMatchMethods(Object clazz)
     // Assert
     assertThat(position.isEmpty(), equalTo(true));
   }
+
+  @Test
+  void shouldTranslateShipName() {
+    Person picardPerson = SampleModelData.PICARD_PERSON;
+    picardPerson.setFavouriteShip(SampleModelData.ENTERPRISE);
+    GenerationOptions generationOptions = new GenerationOptionsBuilder()
+        .withTranslation((s, locale) -> {
+          if (s.equals("USS Enterprise")) {
+            return Optional.of("VSS Unternehmung");
+          } else {
+            return Optional.empty();
+          }
+        }).build();
+    var resolver = new ReflectionResolver(picardPerson, new CustomPlaceholderRegistryImpl(), generationOptions);
+
+    var shipName = resolver.resolve("favouriteShip");
+
+    assertThat(shipName.get().toString(), equalTo("VSS Unternehmung"));
+  }
 }

src/test/java/com/docutools/jocument/sample/model/Person.java

@@ -1,6 +1,7 @@
 package com.docutools.jocument.sample.model;
 
 import com.docutools.jocument.annotations.Format;
+import com.docutools.jocument.annotations.Translatable;
 import java.time.Instant;
 import java.time.LocalDate;
 import java.time.Period;
@@ -13,6 +14,8 @@ public class Person {
   @Format(value = "dd.MM.yyyy")
   private final LocalDate birthDate;
   private final Instant entryDate;
+  @Translatable(toStringMethod = "shipName")
+  private Ship favouriteShip;
 
   public Person(String firstName, String lastName, LocalDate birthDate) {
     this.firstName = firstName;
@@ -44,4 +47,12 @@ public int getAge() {
   public Instant getEntryDate() {
     return entryDate;
   }
+
+  public void setFavouriteShip(Ship favouriteShip) {
+    this.favouriteShip = favouriteShip;
+  }
+
+  public Ship getFavouriteShip() {
+    return favouriteShip;
+  }
 }

src/test/java/com/docutools/jocument/sample/model/Ship.java

@@ -32,4 +32,7 @@ public Optional<String> getNumberOfServices(String placeholder) {
     return Optional.of(String.valueOf(services.size()));
   }
 
+  public String shipName() {
+    return this.name;
+  }
 }