Locale aware converters

xwork-core/src/main/java/com/opensymphony/xwork2/conversion/InternalConverter.java

@@ -0,0 +1,12 @@
+package com.opensymphony.xwork2.conversion;
+
+/**
+ * Represents specialized converters which can convert value to given type T
+ */
+public interface InternalConverter<T> {
+
+    boolean canConvert(Object value);
+
+    T convert(Object value);
+
+}

xwork-core/src/main/java/com/opensymphony/xwork2/conversion/InternalConverters.java

@@ -0,0 +1,37 @@
+package com.opensymphony.xwork2.conversion;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Holds reference to all internal converters to simplify lookup and registration
+ */
+public class InternalConverters<T> {
+
+    private final InternalConverter<T> NO_OP_CONVERTER = new InternalConverter<T>() {
+
+        public boolean canConvert(Object value) {
+            return false;
+        }
+
+        public T convert(Object value) {
+            return null;
+        }
+    };
+
+    private List<InternalConverter<T>> converters = new ArrayList<InternalConverter<T>>();
+
+    public boolean register(InternalConverter<T> converter) {
+        return converters.add(converter);
+    }
+
+    public InternalConverter<T> lookup(Object value) {
+        for (InternalConverter<T> converter : converters) {
+            if (converter.canConvert(value)) {
+                return converter;
+            }
+        }
+        return NO_OP_CONVERTER;
+    }
+
+}

xwork-core/src/main/java/com/opensymphony/xwork2/conversion/impl/StringConverter.java

@@ -1,5 +1,10 @@
 package com.opensymphony.xwork2.conversion.impl;
 
+import com.opensymphony.xwork2.LocaleProvider;
+import com.opensymphony.xwork2.conversion.InternalConverter;
+import com.opensymphony.xwork2.conversion.InternalConverters;
+import com.opensymphony.xwork2.conversion.string.StringDoubleConverter;
+import com.opensymphony.xwork2.inject.Inject;
 import org.apache.commons.lang3.StringUtils;
 
 import java.lang.reflect.Member;
@@ -12,9 +17,18 @@
 
 public class StringConverter extends DefaultTypeConverter {
 
+
+    private InternalConverters<String> converters = new InternalConverters<String>();
+
     @Override
     public Object convertValue(Map<String, Object> context, Object target, Member member, String propertyName, Object value, Class toType) {
-        String result = null;
+        String result;
+
+        InternalConverter<String> converter = converters.lookup(value);
+        result = converter.convert(value);
+        if (result != null) {
+            return result;
+        }
 
         if (value instanceof int[]) {
             int[] x = (int[]) value;
@@ -70,4 +84,13 @@ public Object convertValue(Map<String, Object> context, Object target, Member me
         }
         return result;
     }
+
+    @Inject
+    public void setLocaleProvider(LocaleProvider provider) {
+        super.setLocaleProvider(provider);
+
+        converters = new InternalConverters<String>();
+        converters.register(new StringDoubleConverter(provider));
+    }
+
 }

xwork-core/src/main/java/com/opensymphony/xwork2/conversion/string/StringDoubleConverter.java

@@ -0,0 +1,25 @@
+package com.opensymphony.xwork2.conversion.string;
+
+import com.opensymphony.xwork2.LocaleProvider;
+import com.opensymphony.xwork2.conversion.InternalConverter;
+
+import java.text.NumberFormat;
+
+public class StringDoubleConverter implements InternalConverter<String> {
+
+    private LocaleProvider provider;
+
+    public StringDoubleConverter(LocaleProvider provider) {
+        this.provider = provider;
+    }
+
+    public boolean canConvert(Object value) {
+        return value.getClass() == Double.class || value.getClass() == double.class;
+    }
+
+    public String convert(Object value) {
+        NumberFormat format = NumberFormat.getNumberInstance(provider.getLocale());
+        return format.format(value);
+    }
+
+}

xwork-core/src/test/java/com/opensymphony/xwork2/conversion/impl/StringConverterTest.java

@@ -0,0 +1,36 @@
+package com.opensymphony.xwork2.conversion.impl;
+
+import com.opensymphony.xwork2.LocaleProvider;
+import com.opensymphony.xwork2.XWorkTestCase;
+
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+
+public class StringConverterTest extends XWorkTestCase {
+
+    private Map<String, Object> context = new HashMap<String, Object>();
+
+    public void testDoubleToString() throws Exception {
+        // given
+        Double d = 10.01;
+
+        StringConverter converter = new StringConverter();
+        converter.setLocaleProvider(buildProvider("DE"));
+
+        // when
+        Object actual = converter.convertValue(context, null, null, null, d, String.class);
+
+        // then
+        assertEquals("10,01", actual);
+    }
+
+    private LocaleProvider buildProvider(final String locale) {
+        return new LocaleProvider() {
+            public Locale getLocale() {
+                return new Locale(locale);
+            }
+        };
+    }
+
+}