Harmonize default converters

Provide Converter implementations for Charset, Currency and TimeZone as
related PropertyEditors are available for those.

Issue: SPR-13020

Author: snicoll

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

@@ -16,6 +16,8 @@
 
 package org.springframework.core.convert.support;
 
+import java.nio.charset.Charset;
+import java.util.Currency;
 import java.util.Locale;
 import java.util.UUID;
 
@@ -75,7 +77,7 @@ public static void addDefaultConverters(ConverterRegistry converterRegistry) {
 
 		converterRegistry.addConverter(new ByteBufferConverter((ConversionService) converterRegistry));
 		if (jsr310Available) {
-			Jsr310ConverterRegistrar.registerZoneIdConverters(converterRegistry);
+			Jsr310ConverterRegistrar.registerJsr310Converters(converterRegistry);
 		}
 
 		converterRegistry.addConverter(new ObjectToObjectConverter());
@@ -110,6 +112,12 @@ private static void addScalarConverters(ConverterRegistry converterRegistry) {
 		converterRegistry.addConverter(new StringToLocaleConverter());
 		converterRegistry.addConverter(Locale.class, String.class, new ObjectToStringConverter());
 
+		converterRegistry.addConverter(new StringToCharsetConverter());
+		converterRegistry.addConverter(Charset.class, String.class, new ObjectToStringConverter());
+
+		converterRegistry.addConverter(new StringToCurrencyConverter());
+		converterRegistry.addConverter(Currency.class, String.class, new ObjectToStringConverter());
+
 		converterRegistry.addConverter(new StringToPropertiesConverter());
 		converterRegistry.addConverter(new PropertiesToStringConverter());
 
@@ -150,7 +158,8 @@ private static void addCollectionConverters(ConverterRegistry converterRegistry)
 	 */
 	private static final class Jsr310ConverterRegistrar {
 
-		public static void registerZoneIdConverters(ConverterRegistry converterRegistry) {
+		public static void registerJsr310Converters(ConverterRegistry converterRegistry) {
+			converterRegistry.addConverter(new StringToTimeZoneConverter());
 			converterRegistry.addConverter(new ZoneIdToTimeZoneConverter());
 			converterRegistry.addConverter(new ZonedDateTimeToCalendarConverter());
 		}

spring-core/src/main/java/org/springframework/core/convert/support/StringToCharsetConverter.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2002-2015 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.nio.charset.Charset;
+
+import org.springframework.core.convert.converter.Converter;
+
+/**
+ * Convert a String to a {@link Charset}.
+ *
+ * @author Stephane Nicoll
+ * @since 4.2
+ */
+public class StringToCharsetConverter implements Converter<String, Charset> {
+
+	@Override
+	public Charset convert(String source) {
+		return Charset.forName(source);
+	}
+
+}

spring-core/src/main/java/org/springframework/core/convert/support/StringToCurrencyConverter.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2002-2015 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.util.Currency;
+
+import org.springframework.core.convert.converter.Converter;
+
+/**
+ * Convert a String to a {@link Currency}.
+ *
+ * @author Stephane Nicoll
+ * @since 4.2
+ */
+class StringToCurrencyConverter implements Converter<String, Currency> {
+
+	@Override
+	public Currency convert(String source) {
+		return Currency.getInstance(source);
+	}
+
+}

spring-core/src/main/java/org/springframework/core/convert/support/StringToTimeZoneConverter.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2002-2015 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.util.TimeZone;
+
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.lang.UsesJava8;
+import org.springframework.util.StringUtils;
+
+/**
+ * Convert a String to a {@link TimeZone}.
+ *
+ * @author Stephane Nicoll
+ * @since 4.2
+ */
+@UsesJava8
+class StringToTimeZoneConverter implements Converter<String, TimeZone> {
+
+	@Override
+	public TimeZone convert(String source) {
+		return StringUtils.parseTimeZoneString(source);
+	}
+
+}

spring-core/src/test/java/org/springframework/core/convert/support/DefaultConversionServiceTests.java

@@ -20,12 +20,14 @@
 import java.lang.reflect.Method;
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.nio.charset.Charset;
 import java.time.ZoneId;
 import java.util.AbstractList;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Currency;
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
@@ -37,6 +39,7 @@
 import java.util.Optional;
 import java.util.Properties;
 import java.util.Set;
+import java.util.TimeZone;
 import java.util.UUID;
 import java.util.stream.Stream;
 
@@ -277,6 +280,26 @@ public void testStringToLocale() {
 		assertEquals(Locale.ENGLISH, conversionService.convert("en", Locale.class));
 	}
 
+	@Test
+	public void testStringToCharset() {
+		assertEquals(Charset.forName("UTF-8"), conversionService.convert("UTF-8", Charset.class));
+	}
+
+	@Test
+	public void testCharsetToString() {
+		assertEquals("UTF-8", conversionService.convert(Charset.forName("UTF-8"), String.class));
+	}
+
+	@Test
+	public void testStringToCurrency() {
+		assertEquals(Currency.getInstance("EUR"), conversionService.convert("EUR", Currency.class));
+	}
+
+	@Test
+	public void testCurrencyToString() {
+		assertEquals("USD", conversionService.convert(Currency.getInstance("USD"), String.class));
+	}
+
 	@Test
 	public void testStringToString() {
 		String str = "test";
@@ -801,6 +824,11 @@ public void convertObjectToObjectUsingObjectConstructor() {
 		assertEquals("toString() invocations", 0, SSN.toStringCount);
 	}
 
+	@Test
+	public void convertStringToTimezone() {
+		assertEquals("GMT+02:00", conversionService.convert("GMT+2", TimeZone.class).getID());
+	}
+
 	@Test
 	public void convertObjectToStringWithJavaTimeOfMethodPresent() {
 		assertTrue(conversionService.convert(ZoneId.of("GMT+1"), String.class).startsWith("GMT+"));