added symmetry to ToString converters: SPR-8306

Author: Keith Donald

org.springframework.core/src/main/java/org/springframework/core/convert/support/DefaultConversionService.java

@@ -16,6 +16,8 @@
 
 package org.springframework.core.convert.support;
 
+import java.util.Locale;
+
 /**
  * A specialization of {@link GenericConversionService} configured by default with
  * converters appropriate for most applications.
@@ -65,19 +67,28 @@ public static void addDefaultConverters(GenericConversionService conversionServi
 		conversionService.addConverter(new StringToPropertiesConverter());
 
 		conversionService.addConverter(new StringToBooleanConverter());
+		conversionService.addConverter(Boolean.class, String.class, new ObjectToStringConverter());
+
 		conversionService.addConverter(new StringToCharacterConverter());
+		conversionService.addConverter(Character.class, String.class, new ObjectToStringConverter());
+
 		conversionService.addConverter(new StringToLocaleConverter());
+		conversionService.addConverter(Locale.class, String.class, new ObjectToStringConverter());
+		
 		conversionService.addConverterFactory(new StringToNumberConverterFactory());
+		conversionService.addConverter(Number.class, String.class, new ObjectToStringConverter());
+		
 		conversionService.addConverterFactory(new StringToEnumConverterFactory());
-
+		conversionService.addConverter(Enum.class, String.class, new EnumToStringConverter());
+		
 		conversionService.addConverter(new NumberToCharacterConverter());
 		conversionService.addConverterFactory(new CharacterToNumberFactory());
 
 		conversionService.addConverterFactory(new NumberToNumberConverterFactory());
 
-		conversionService.addConverter(new ObjectToStringConverter());
 		conversionService.addConverter(new ObjectToObjectConverter());
 		conversionService.addConverter(new IdToEntityConverter(conversionService));
+		conversionService.addConverter(new FallbackObjectToStringConverter());
 	}
 
 }

org.springframework.core/src/main/java/org/springframework/core/convert/support/EnumToStringConverter.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2002-2009 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.convert.support;
+
+import org.springframework.core.convert.converter.Converter;
+
+/**
+ * Simply calls {@link Enum#name()} to convert a source Enum to a String.
+ * @author Keith Donald
+ * @since 3.0
+ */
+final class EnumToStringConverter implements Converter<Enum<?>, String> {
+
+	public String convert(Enum<?> source) {
+		return source.name();
+	}
+
+}

org.springframework.core/src/main/java/org/springframework/core/convert/support/FallbackObjectToStringConverter.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2002-2009 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.core.convert.support;
+
+import java.io.StringWriter;
+import java.util.Collections;
+import java.util.Set;
+
+import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.core.convert.converter.ConditionalGenericConverter;
+
+/**
+ * Simply calls {@link Object#toString()} to convert any supported Object to a String.
+ * Supports CharSequence, StringWriter, and any class with a String constructor or <code>valueOf(String)</code> method.
+ *
+ * <p>Used by the default ConversionService as a fallback if there are no other explicit
+ * to-String converters registered.
+ *
+ * @author Keith Donald
+ * @author Juergen Hoeller
+ * @since 3.0
+ */
+final class FallbackObjectToStringConverter implements ConditionalGenericConverter {
+
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object.class, String.class));
+	}
+
+	public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
+		Class<?> sourceClass = sourceType.getObjectType();
+		return CharSequence.class.isAssignableFrom(sourceClass) || StringWriter.class.isAssignableFrom(sourceClass) ||
+			ObjectToObjectConverter.hasValueOfMethodOrConstructor(sourceClass, String.class);
+	}
+
+	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
+		return (source != null ? source.toString() : null);
+	}
+
+}

org.springframework.core/src/main/java/org/springframework/core/convert/support/GenericConversionService.java

@@ -88,6 +88,17 @@ public String toString() {
 			new ConcurrentHashMap<ConverterCacheKey, GenericConverter>();
 
 
+	/**
+	 * Add a converter to the register indexed under the explicit source and target types.
+	 * Allows for a general converter to be reused for multiple distinct source-to-target convertible pairs without having to create a Converter class for each pair.
+	 * Not yet part of the ConverterRegistry interface.
+	 * @since 3.1
+	 */
+	public void addConverter(Class<?> sourceType, Class<?> targetType, Converter<?, ?> converter) {
+		GenericConverter.ConvertiblePair typeInfo = new GenericConverter.ConvertiblePair(sourceType, targetType);
+		addConverter(new ConverterAdapter(typeInfo, converter));
+	}
+	
 	// implementing ConverterRegistry
 
 	public void addConverter(Converter<?, ?> converter) {

org.springframework.core/src/main/java/org/springframework/core/convert/support/ObjectToObjectConverter.java

@@ -43,16 +43,16 @@
  */
 final class ObjectToObjectConverter implements ConditionalGenericConverter {
 
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object.class, Object.class));
+	}
+
 	public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
 		Class<?> source = sourceType.getObjectType();
 		Class<?> target = targetType.getObjectType();
 		return (!source.equals(target) && hasValueOfMethodOrConstructor(target, source));
 	}
 
-	public Set<ConvertiblePair> getConvertibleTypes() {
-		return Collections.singleton(new ConvertiblePair(Object.class, Object.class));
-	}
-
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 		Class<?> sourceClass = sourceType.getObjectType();
 		Class<?> targetClass = targetType.getObjectType();

org.springframework.core/src/main/java/org/springframework/core/convert/support/ObjectToStringConverter.java

@@ -16,40 +16,17 @@
 
 package org.springframework.core.convert.support;
 
-import java.io.StringWriter;
-import java.util.Collections;
-import java.util.Set;
-
-import org.springframework.core.convert.TypeDescriptor;
-import org.springframework.core.convert.converter.ConditionalGenericConverter;
+import org.springframework.core.convert.converter.Converter;
 
 /**
- * Simply calls {@link Object#toString()} to convert any supported Object to a String.
- * Supports Number, Boolean, Character, CharSequence, StringWriter, any enum,
- * and any class with a String constructor or <code>valueOf(String)</code> method.
- *
- * <p>Used by the default ConversionService as a fallback if there are no other explicit
- * to-String converters registered.
- *
+ * Simply calls {@link Object#toString()} to convert a source Object to a String.
  * @author Keith Donald
- * @author Juergen Hoeller
  * @since 3.0
  */
-final class ObjectToStringConverter implements ConditionalGenericConverter {
-
-	public Set<ConvertiblePair> getConvertibleTypes() {
-		return Collections.singleton(new ConvertiblePair(Object.class, String.class));
-	}
-
-	public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
-		Class<?> sourceClass = sourceType.getObjectType();
-		return CharSequence.class.isAssignableFrom(sourceClass) || Number.class.isAssignableFrom(sourceClass) || 
-				Boolean.class.equals(sourceClass) || Character.class.equals(sourceClass) || StringWriter.class.isAssignableFrom(sourceClass) ||
-				sourceClass.isEnum() || ObjectToObjectConverter.hasValueOfMethodOrConstructor(sourceClass, String.class);
-	}
+final class ObjectToStringConverter implements Converter<Object, String> {
 
-	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
-		return (source != null ? source.toString() : null);
+	public String convert(Object source) {
+		return source.toString();
 	}
 
 }

org.springframework.core/src/main/java/org/springframework/core/convert/support/StringToBooleanConverter.java

@@ -36,15 +36,13 @@ final class StringToBooleanConverter implements Converter<String, Boolean> {
 
 	static {
 		trueValues.add("true");
-		falseValues.add("false");
-
 		trueValues.add("on");
-		falseValues.add("off");
-
 		trueValues.add("yes");
-		falseValues.add("no");
-
 		trueValues.add("1");
+
+		falseValues.add("false");
+		falseValues.add("off");
+		falseValues.add("no");
 		falseValues.add("0");
 	}
 
@@ -53,7 +51,8 @@ public Boolean convert(String source) {
 		if (value.length() == 0) {
 			return null;
 		}
-		else if (trueValues.contains(value)) {
+		value = value.toLowerCase();
+		if (trueValues.contains(value)) {
 			return Boolean.TRUE;
 		}
 		else if (falseValues.contains(value)) {

org.springframework.core/src/test/java/org/springframework/core/convert/support/DefaultConversionTests.java

@@ -79,6 +79,9 @@ public void testStringToBooleanTrue() {
 		assertEquals(Boolean.valueOf(true), conversionService.convert("on", Boolean.class));
 		assertEquals(Boolean.valueOf(true), conversionService.convert("yes", Boolean.class));
 		assertEquals(Boolean.valueOf(true), conversionService.convert("1", Boolean.class));
+		assertEquals(Boolean.valueOf(true), conversionService.convert("TRUE", Boolean.class));
+		assertEquals(Boolean.valueOf(true), conversionService.convert("ON", Boolean.class));
+		assertEquals(Boolean.valueOf(true), conversionService.convert("YES", Boolean.class));
 	}
 
 	@Test
@@ -87,6 +90,9 @@ public void testStringToBooleanFalse() {
 		assertEquals(Boolean.valueOf(false), conversionService.convert("off", Boolean.class));
 		assertEquals(Boolean.valueOf(false), conversionService.convert("no", Boolean.class));
 		assertEquals(Boolean.valueOf(false), conversionService.convert("0", Boolean.class));
+		assertEquals(Boolean.valueOf(false), conversionService.convert("FALSE", Boolean.class));
+		assertEquals(Boolean.valueOf(false), conversionService.convert("OFF", Boolean.class));
+		assertEquals(Boolean.valueOf(false), conversionService.convert("NO", Boolean.class));
 	}
 
 	@Test