org.springframework.core.convert.support.DefaultConversionService Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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
*
* https://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 java.util.Currency;
import java.util.Locale;
import java.util.UUID;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.converter.ConverterRegistry;
import org.springframework.util.ClassUtils;
/**
* A specialization of {@link GenericConversionService} configured by default
* with converters appropriate for most environments.
*
* Designed for direct instantiation but also exposes the static
* {@link #addDefaultConverters(ConverterRegistry)} utility method for ad-hoc
* use against any {@code ConverterRegistry} instance.
*
* @author Chris Beams
* @author Juergen Hoeller
* @author Stephane Nicoll
* @since 3.1
*/
public class DefaultConversionService extends GenericConversionService {
/** Java 8's java.util.Optional class available? */
private static final boolean javaUtilOptionalClassAvailable =
ClassUtils.isPresent("java.util.Optional", DefaultConversionService.class.getClassLoader());
/** Java 8's java.time package available? */
private static final boolean jsr310Available =
ClassUtils.isPresent("java.time.ZoneId", DefaultConversionService.class.getClassLoader());
/** Java 8's java.util.stream.Stream class available? */
private static final boolean streamAvailable = ClassUtils.isPresent(
"java.util.stream.Stream", DefaultConversionService.class.getClassLoader());
private static volatile DefaultConversionService sharedInstance;
/**
* Create a new {@code DefaultConversionService} with the set of
* {@linkplain DefaultConversionService#addDefaultConverters(ConverterRegistry) default converters}.
*/
public DefaultConversionService() {
addDefaultConverters(this);
}
/**
* Return a shared default {@code ConversionService} instance,
* lazily building it once needed.
*
NOTE: We highly recommend constructing individual
* {@code ConversionService} instances for customization purposes.
* This accessor is only meant as a fallback for code paths which
* need simple type coercion but cannot access a longer-lived
* {@code ConversionService} instance any other way.
* @return the shared {@code ConversionService} instance (never {@code null})
* @since 4.3.5
*/
public static ConversionService getSharedInstance() {
if (sharedInstance == null) {
synchronized (DefaultConversionService.class) {
if (sharedInstance == null) {
sharedInstance = new DefaultConversionService();
}
}
}
return sharedInstance;
}
/**
* Add converters appropriate for most environments.
* @param converterRegistry the registry of converters to add to
* (must also be castable to ConversionService, e.g. being a {@link ConfigurableConversionService})
* @throws ClassCastException if the given ConverterRegistry could not be cast to a ConversionService
*/
public static void addDefaultConverters(ConverterRegistry converterRegistry) {
addScalarConverters(converterRegistry);
addCollectionConverters(converterRegistry);
converterRegistry.addConverter(new ByteBufferConverter((ConversionService) converterRegistry));
if (jsr310Available) {
Jsr310ConverterRegistrar.registerJsr310Converters(converterRegistry);
}
converterRegistry.addConverter(new ObjectToObjectConverter());
converterRegistry.addConverter(new IdToEntityConverter((ConversionService) converterRegistry));
converterRegistry.addConverter(new FallbackObjectToStringConverter());
if (javaUtilOptionalClassAvailable) {
converterRegistry.addConverter(new ObjectToOptionalConverter((ConversionService) converterRegistry));
}
}
/**
* Add common collection converters.
* @param converterRegistry the registry of converters to add to
* (must also be castable to ConversionService, e.g. being a {@link ConfigurableConversionService})
* @throws ClassCastException if the given ConverterRegistry could not be cast to a ConversionService
* @since 4.2.3
*/
public static void addCollectionConverters(ConverterRegistry converterRegistry) {
ConversionService conversionService = (ConversionService) converterRegistry;
converterRegistry.addConverter(new ArrayToCollectionConverter(conversionService));
converterRegistry.addConverter(new CollectionToArrayConverter(conversionService));
converterRegistry.addConverter(new ArrayToArrayConverter(conversionService));
converterRegistry.addConverter(new CollectionToCollectionConverter(conversionService));
converterRegistry.addConverter(new MapToMapConverter(conversionService));
converterRegistry.addConverter(new ArrayToStringConverter(conversionService));
converterRegistry.addConverter(new StringToArrayConverter(conversionService));
converterRegistry.addConverter(new ArrayToObjectConverter(conversionService));
converterRegistry.addConverter(new ObjectToArrayConverter(conversionService));
converterRegistry.addConverter(new CollectionToStringConverter(conversionService));
converterRegistry.addConverter(new StringToCollectionConverter(conversionService));
converterRegistry.addConverter(new CollectionToObjectConverter(conversionService));
converterRegistry.addConverter(new ObjectToCollectionConverter(conversionService));
if (streamAvailable) {
converterRegistry.addConverter(new StreamConverter(conversionService));
}
}
private static void addScalarConverters(ConverterRegistry converterRegistry) {
converterRegistry.addConverterFactory(new NumberToNumberConverterFactory());
converterRegistry.addConverterFactory(new StringToNumberConverterFactory());
converterRegistry.addConverter(Number.class, String.class, new ObjectToStringConverter());
converterRegistry.addConverter(new StringToCharacterConverter());
converterRegistry.addConverter(Character.class, String.class, new ObjectToStringConverter());
converterRegistry.addConverter(new NumberToCharacterConverter());
converterRegistry.addConverterFactory(new CharacterToNumberFactory());
converterRegistry.addConverter(new StringToBooleanConverter());
converterRegistry.addConverter(Boolean.class, String.class, new ObjectToStringConverter());
converterRegistry.addConverterFactory(new StringToEnumConverterFactory());
converterRegistry.addConverter(new EnumToStringConverter((ConversionService) converterRegistry));
converterRegistry.addConverterFactory(new IntegerToEnumConverterFactory());
converterRegistry.addConverter(new EnumToIntegerConverter((ConversionService) 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());
converterRegistry.addConverter(new StringToUUIDConverter());
converterRegistry.addConverter(UUID.class, String.class, new ObjectToStringConverter());
}
/**
* Inner class to avoid a hard-coded dependency on Java 8's {@code java.time} package.
*/
private static final class Jsr310ConverterRegistrar {
public static void registerJsr310Converters(ConverterRegistry converterRegistry) {
converterRegistry.addConverter(new StringToTimeZoneConverter());
converterRegistry.addConverter(new ZoneIdToTimeZoneConverter());
converterRegistry.addConverter(new ZonedDateTimeToCalendarConverter());
}
}
}