/*
 * Copyright 2012-2020 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.boot.convert;

import java.util.LinkedHashSet;
import java.util.Set;

import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.converter.Converter;
import org.springframework.core.convert.converter.ConverterRegistry;
import org.springframework.core.convert.converter.GenericConverter;
import org.springframework.core.convert.support.ConfigurableConversionService;
import org.springframework.core.convert.support.DefaultConversionService;
import org.springframework.format.Formatter;
import org.springframework.format.FormatterRegistry;
import org.springframework.format.Parser;
import org.springframework.format.Printer;
import org.springframework.format.support.DefaultFormattingConversionService;
import org.springframework.format.support.FormattingConversionService;
import org.springframework.util.StringValueResolver;

A specialization of FormattingConversionService configured by default with converters and formatters appropriate for most Spring Boot applications. 
 Designed for direct instantiation but also exposes the static addApplicationConverters and addApplicationFormatters(FormatterRegistry) utility methods for ad-hoc use against registry instance. 
Author:
Phillip Webb
Since:
2.0.0/**
 * A specialization of {@link FormattingConversionService} configured by default with
 * converters and formatters appropriate for most Spring Boot applications.
 * <p>
 * Designed for direct instantiation but also exposes the static
 * {@link #addApplicationConverters} and
 * {@link #addApplicationFormatters(FormatterRegistry)} utility methods for ad-hoc use
 * against registry instance.
 *
 * @author Phillip Webb
 * @since 2.0.0
 */
public class ApplicationConversionService extends FormattingConversionService {

	private static volatile ApplicationConversionService sharedInstance;

	public ApplicationConversionService() {
		this(null);
	}

	public ApplicationConversionService(StringValueResolver embeddedValueResolver) {
		if (embeddedValueResolver != null) {
			setEmbeddedValueResolver(embeddedValueResolver);
		}
		configure(this);
	}

	
Return a shared default application ConversionService instance, lazily building it once needed. 
 Note: This method actually returns an ApplicationConversionService instance. However, the ConversionService signature has been preserved for binary compatibility. 
Returns:
the shared ApplicationConversionService instance (never null)/**
	 * Return a shared default application {@code ConversionService} instance, lazily
	 * building it once needed.
	 * <p>
	 * Note: This method actually returns an {@link ApplicationConversionService}
	 * instance. However, the {@code ConversionService} signature has been preserved for
	 * binary compatibility.
	 * @return the shared {@code ApplicationConversionService} instance (never
	 * {@code null})
	 */
	public static ConversionService getSharedInstance() {
		ApplicationConversionService sharedInstance = ApplicationConversionService.sharedInstance;
		if (sharedInstance == null) {
			synchronized (ApplicationConversionService.class) {
				sharedInstance = ApplicationConversionService.sharedInstance;
				if (sharedInstance == null) {
					sharedInstance = new ApplicationConversionService();
					ApplicationConversionService.sharedInstance = sharedInstance;
				}
			}
		}
		return sharedInstance;
	}

	
Configure the given FormatterRegistry with formatters and converters appropriate for most Spring Boot applications. 
Params:
registry – the registry of converters to add to (must also be castable to ConversionService, e.g. being a ConfigurableConversionService)
Throws:
ClassCastException – if the given FormatterRegistry could not be cast to a
ConversionService/**
	 * Configure the given {@link FormatterRegistry} with formatters and converters
	 * appropriate for most Spring Boot applications.
	 * @param registry the registry of converters to add to (must also be castable to
	 * ConversionService, e.g. being a {@link ConfigurableConversionService})
	 * @throws ClassCastException if the given FormatterRegistry could not be cast to a
	 * ConversionService
	 */
	public static void configure(FormatterRegistry registry) {
		DefaultConversionService.addDefaultConverters(registry);
		DefaultFormattingConversionService.addDefaultFormatters(registry);
		addApplicationFormatters(registry);
		addApplicationConverters(registry);
	}

	
Add converters useful for most Spring Boot applications.
Params:
registry – the registry of converters to add to (must also be castable to ConversionService, e.g. being a ConfigurableConversionService)
Throws:
ClassCastException – if the given ConverterRegistry could not be cast to a
ConversionService/**
	 * Add converters useful for most Spring Boot applications.
	 * @param registry 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 addApplicationConverters(ConverterRegistry registry) {
		addDelimitedStringConverters(registry);
		registry.addConverter(new StringToDurationConverter());
		registry.addConverter(new DurationToStringConverter());
		registry.addConverter(new NumberToDurationConverter());
		registry.addConverter(new DurationToNumberConverter());
		registry.addConverter(new StringToPeriodConverter());
		registry.addConverter(new PeriodToStringConverter());
		registry.addConverter(new NumberToPeriodConverter());
		registry.addConverter(new StringToDataSizeConverter());
		registry.addConverter(new NumberToDataSizeConverter());
		registry.addConverter(new StringToFileConverter());
		registry.addConverter(new InputStreamSourceToByteArrayConverter());
		registry.addConverterFactory(new LenientStringToEnumConverterFactory());
		registry.addConverterFactory(new LenientBooleanToEnumConverterFactory());
		if (registry instanceof ConversionService) {
			addApplicationConverters(registry, (ConversionService) registry);
		}
	}

	private static void addApplicationConverters(ConverterRegistry registry, ConversionService conversionService) {
		registry.addConverter(new CharSequenceToObjectConverter(conversionService));
	}

	
Add converters to support delimited strings.
Params:
registry – the registry of converters to add to (must also be castable to ConversionService, e.g. being a ConfigurableConversionService)
Throws:
ClassCastException – if the given ConverterRegistry could not be cast to a
ConversionService/**
	 * Add converters to support delimited strings.
	 * @param registry 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 addDelimitedStringConverters(ConverterRegistry registry) {
		ConversionService service = (ConversionService) registry;
		registry.addConverter(new ArrayToDelimitedStringConverter(service));
		registry.addConverter(new CollectionToDelimitedStringConverter(service));
		registry.addConverter(new DelimitedStringToArrayConverter(service));
		registry.addConverter(new DelimitedStringToCollectionConverter(service));
	}

	
Add formatters useful for most Spring Boot applications.
Params:
registry – the service to register default formatters with/**
	 * Add formatters useful for most Spring Boot applications.
	 * @param registry the service to register default formatters with
	 */
	public static void addApplicationFormatters(FormatterRegistry registry) {
		registry.addFormatter(new CharArrayFormatter());
		registry.addFormatter(new InetAddressFormatter());
		registry.addFormatter(new IsoOffsetFormatter());
	}

	
Add GenericConverter, Converter, Printer, Parser and Formatter beans from the specified context. 
Params:
registry – the service to register beans with
beanFactory – the bean factory to get the beans from
Since:
2.2.0/**
	 * Add {@link GenericConverter}, {@link Converter}, {@link Printer}, {@link Parser}
	 * and {@link Formatter} beans from the specified context.
	 * @param registry the service to register beans with
	 * @param beanFactory the bean factory to get the beans from
	 * @since 2.2.0
	 */
	public static void addBeans(FormatterRegistry registry, ListableBeanFactory beanFactory) {
		Set<Object> beans = new LinkedHashSet<>();
		beans.addAll(beanFactory.getBeansOfType(GenericConverter.class).values());
		beans.addAll(beanFactory.getBeansOfType(Converter.class).values());
		beans.addAll(beanFactory.getBeansOfType(Printer.class).values());
		beans.addAll(beanFactory.getBeansOfType(Parser.class).values());
		for (Object bean : beans) {
			if (bean instanceof GenericConverter) {
				registry.addConverter((GenericConverter) bean);
			}
			else if (bean instanceof Converter) {
				registry.addConverter((Converter<?, ?>) bean);
			}
			else if (bean instanceof Formatter) {
				registry.addFormatter((Formatter<?>) bean);
			}
			else if (bean instanceof Printer) {
				registry.addPrinter((Printer<?>) bean);
			}
			else if (bean instanceof Parser) {
				registry.addParser((Parser<?>) bean);
			}
		}
	}

}