Adding a Locale-aware ParameterByTypeTransformer

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - [Java] Add OSGi metadata
 ### Added
 - [Java] class `KeyboardFriendlyDecimalFormatSymbols` is now `public` and can be used when creating a custom `Locale`-aware type transformation method ([#376](https://github.com/cucumber/cucumber-expressions/issues/376) [antagoony](https://github.com/antagoony))
+- [Java] interface `LocaleParameterByTypeTransformer` to support `Locale`-aware type transformation ([#376](https://github.com/cucumber/cucumber-expressions/issues/376) [antagoony](https://github.com/antagoony))
 
 ### Removed
 - [Python] Remove support for end-of-life Python 3.8 and 3.9 ([#359](https://github.com/cucumber/cucumber-expressions/pull/359))

java/src/main/java/io/cucumber/cucumberexpressions/BuiltInParameterTransformer.java

@@ -9,7 +9,7 @@
 
 import static java.util.Objects.requireNonNull;
 
-final class BuiltInParameterTransformer implements ParameterByTypeTransformer {
+final class BuiltInParameterTransformer implements LocaleParameterByTypeTransformer {
 
     private final NumberParser numberParser;
 

java/src/main/java/io/cucumber/cucumberexpressions/CucumberExpression.java

@@ -155,8 +155,9 @@ public List<Argument<?>> match(String text, Type... typeHints) {
             ParameterType<?> parameterType = parameterTypes.get(i);
             Type type = i < typeHints.length ? typeHints[i] : String.class;
             if (parameterType.isAnonymous()) {
-                ParameterByTypeTransformer defaultTransformer = parameterTypeRegistry.getDefaultParameterTransformer();
-                parameterTypes.set(i, parameterType.deAnonymize(type, arg -> defaultTransformer.transform(arg, type)));
+                LocaleParameterByTypeTransformer defaultTransformer = parameterTypeRegistry.getDefaultParameterTransformer();
+                parameterTypes.set(i, parameterType.deAnonymize(type, arg -> defaultTransformer.transform(arg, type,
+                    parameterTypeRegistry.getLocale())));
             }
         }
 

java/src/main/java/io/cucumber/cucumberexpressions/LocaleParameterByTypeTransformer.java

@@ -0,0 +1,33 @@
+package io.cucumber.cucumberexpressions;
+
+import java.lang.reflect.Type;
+import java.util.Locale;
+import org.apiguardian.api.API;
+
+/**
+ * This extension of {@link ParameterByTypeTransformer} provides an additional
+ * transform method that consumes a {@link Locale locale}. Intentionally, this
+ * will be the locale information specified within the feature file containing
+ * the currently processed scenario.
+ *
+ * @see KeyboardFriendlyDecimalFormatSymbols
+ */
+@API(status = API.Status.EXPERIMENTAL)
+@FunctionalInterface
+public interface LocaleParameterByTypeTransformer extends ParameterByTypeTransformer {
+
+  /**
+   * Similar to {@link #transform(String, Type)} but, in addition, consumes a
+   * {@link Locale locale}. This locale information can be ignored, or can be
+   * considered in case the transformation is aware of localized values. For
+   * example, numbers {@linkplain KeyboardFriendlyDecimalFormatSymbols may use
+   * localized decimal symbols}.
+   *
+   * @implNote The default implementation ignores the {@code locale} and
+   *           delegates to {@link #transform(String, Type)}
+   */
+  default Object transform(final String fromValue, final Type toValueType, final Locale locale) throws Throwable {
+    return this.transform(fromValue, toValueType);
+  }
+
+}

java/src/main/java/io/cucumber/cucumberexpressions/ParameterTypeRegistry.java

@@ -47,14 +47,16 @@ public final class ParameterTypeRegistry {
      * To maintain consistency with `datatable` we don't use the mutable default
      * transformer to handle build in in conversions yet.
      */
-    private final ParameterByTypeTransformer internalParameterTransformer;
-    private ParameterByTypeTransformer defaultParameterTransformer;
+    private final LocaleParameterByTypeTransformer internalParameterTransformer;
+    private LocaleParameterByTypeTransformer defaultParameterTransformer;
+    private Locale locale;
 
     public ParameterTypeRegistry(Locale locale) {
         this(new BuiltInParameterTransformer(locale), locale);
+        this.locale = locale;
     }
 
-    private ParameterTypeRegistry(ParameterByTypeTransformer defaultParameterTransformer, Locale locale) {
+    private ParameterTypeRegistry(LocaleParameterByTypeTransformer defaultParameterTransformer, Locale locale) {
         this.internalParameterTransformer = defaultParameterTransformer;
         this.defaultParameterTransformer = defaultParameterTransformer;
 
@@ -161,11 +163,21 @@ public void defineParameterType(ParameterType<?> parameterType) {
         }
     }
 
-    ParameterByTypeTransformer getDefaultParameterTransformer() {
+    LocaleParameterByTypeTransformer getDefaultParameterTransformer() {
         return defaultParameterTransformer;
     }
 
     public void setDefaultParameterTransformer(ParameterByTypeTransformer defaultParameterTransformer) {
+        final LocaleParameterByTypeTransformer localeParameterTransformer;
+        if (defaultParameterTransformer instanceof LocaleParameterByTypeTransformer) {
+            localeParameterTransformer = (LocaleParameterByTypeTransformer) defaultParameterTransformer;
+        } else {
+            localeParameterTransformer = defaultParameterTransformer::transform;
+        }
+        setDefaultParameterTransformer(localeParameterTransformer);
+    }
+
+    public void setDefaultParameterTransformer(LocaleParameterByTypeTransformer defaultParameterTransformer) {
         this.defaultParameterTransformer = defaultParameterTransformer;
     }
 
@@ -186,6 +198,10 @@ <T> ParameterType<T> lookupByRegexp(String parameterTypeRegexp, Pattern expressi
         return (ParameterType<T>) parameterTypes.first();
     }
 
+    Locale getLocale() {
+        return locale;
+    }
+
     Collection<ParameterType<?>> getParameterTypes() {
         return parameterTypeByName.values();
     }

java/src/main/java/io/cucumber/cucumberexpressions/RegularExpression.java

@@ -36,7 +36,7 @@ public List<Argument<?>> match(String text, Type... typeHints) {
             return null;
         }
 
-        final ParameterByTypeTransformer defaultTransformer = parameterTypeRegistry.getDefaultParameterTransformer();
+        final LocaleParameterByTypeTransformer defaultTransformer = parameterTypeRegistry.getDefaultParameterTransformer();
         final List<ParameterType<?>> parameterTypes = new ArrayList<>();
         int typeHintIndex = 0;
         for (GroupBuilder groupBuilder : treeRegexp.getGroupBuilder().getChildren()) {
@@ -63,7 +63,8 @@ public List<Argument<?>> match(String text, Type... typeHints) {
 
             // Either from createAnonymousParameterType or lookupByRegexp
             if (parameterType.isAnonymous()) {
-                parameterType = parameterType.deAnonymize(typeHint, arg -> defaultTransformer.transform(arg, typeHint));
+                parameterType = parameterType.deAnonymize(typeHint, arg -> defaultTransformer.transform(arg, typeHint,
+                    parameterTypeRegistry.getLocale()));
             }
 
             parameterTypes.add(parameterType);