/*
 * 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.format.support;

import java.util.Set;

import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.EmbeddedValueResolverAware;
import org.springframework.core.convert.support.ConversionServiceFactory;
import org.springframework.format.AnnotationFormatterFactory;
import org.springframework.format.Formatter;
import org.springframework.format.FormatterRegistrar;
import org.springframework.format.FormatterRegistry;
import org.springframework.format.Parser;
import org.springframework.format.Printer;
import org.springframework.lang.Nullable;
import org.springframework.util.StringValueResolver;

/**
 * A factory providing convenient access to a {@code FormattingConversionService}
 * configured with converters and formatters for common types such as numbers and
 * datetimes.
 *
 * <p>Additional converters and formatters can be registered declaratively through
 * {@link #setConverters(Set)} and {@link #setFormatters(Set)}. Another option
 * is to register converters and formatters in code by implementing the
 * {@link FormatterRegistrar} interface. You can then configure provide the set
 * of registrars to use through {@link #setFormatterRegistrars(Set)}.
 *
 * <p>A good example for registering converters and formatters in code is
 * {@code JodaTimeFormatterRegistrar}, which registers a number of
 * date-related formatters and converters. For a more detailed list of cases
 * see {@link #setFormatterRegistrars(Set)}
 *
 * <p>Like all {@code FactoryBean} implementations, this class is suitable for
 * use when configuring a Spring application context using Spring {@code <beans>}
 * XML. When configuring the container with
 * {@link org.springframework.context.annotation.Configuration @Configuration}
 * classes, simply instantiate, configure and return the appropriate
 * {@code FormattingConversionService} object from a
 * {@link org.springframework.context.annotation.Bean @Bean} method.
 *
 * @author Keith Donald
 * @author Juergen Hoeller
 * @author Rossen Stoyanchev
 * @author Chris Beams
 * @since 3.0
 */
public class FormattingConversionServiceFactoryBean
                implements FactoryBean<FormattingConversionService>, EmbeddedValueResolverAware, InitializingBean {

        @Nullable
        private Set<?> converters;

        @Nullable
        private Set<?> formatters;

        @Nullable
        private Set<FormatterRegistrar> formatterRegistrars;

        private boolean registerDefaultFormatters = true;

        @Nullable
        private StringValueResolver embeddedValueResolver;

        @Nullable
        private FormattingConversionService conversionService;


        /**
         * Configure the set of custom converter objects that should be added.
         * @param converters instances of any of the following:
         * {@link org.springframework.core.convert.converter.Converter},
         * {@link org.springframework.core.convert.converter.ConverterFactory},
         * {@link org.springframework.core.convert.converter.GenericConverter}
         */
        public void setConverters(Set<?> converters) {
                this.converters = converters;
        }

        /**
         * Configure the set of custom formatter objects that should be added.
         * @param formatters instances of {@link Formatter} or {@link AnnotationFormatterFactory}
         */
        public void setFormatters(Set<?> formatters) {
                this.formatters = formatters;
        }

        /**
         * <p>Configure the set of FormatterRegistrars to invoke to register
         * Converters and Formatters in addition to those added declaratively
         * via {@link #setConverters(Set)} and {@link #setFormatters(Set)}.
         * <p>FormatterRegistrars are useful when registering multiple related
         * converters and formatters for a formatting category, such as Date
         * formatting. All types related needed to support the formatting
         * category can be registered from one place.
         * <p>FormatterRegistrars can also be used to register Formatters
         * indexed under a specific field type different from its own &lt;T&gt;,
         * or when registering a Formatter from a Printer/Parser pair.
         * @see FormatterRegistry#addFormatterForFieldType(Class, Formatter)
         * @see FormatterRegistry#addFormatterForFieldType(Class, Printer, Parser)
         */
        public void setFormatterRegistrars(Set<FormatterRegistrar> formatterRegistrars) {
                this.formatterRegistrars = formatterRegistrars;
        }

        /**
         * Indicate whether default formatters should be registered or not.
         * <p>By default, built-in formatters are registered. This flag can be used
         * to turn that off and rely on explicitly registered formatters only.
         * @see #setFormatters(Set)
         * @see #setFormatterRegistrars(Set)
         */
        public void setRegisterDefaultFormatters(boolean registerDefaultFormatters) {
                this.registerDefaultFormatters = registerDefaultFormatters;
        }

        @Override
        public void setEmbeddedValueResolver(StringValueResolver embeddedValueResolver) {
                this.embeddedValueResolver = embeddedValueResolver;
        }


        @Override
        public void afterPropertiesSet() {
                this.conversionService = new DefaultFormattingConversionService(this.embeddedValueResolver, this.registerDefaultFormatters);
                ConversionServiceFactory.registerConverters(this.converters, this.conversionService);
                registerFormatters(this.conversionService);
        }

        private void registerFormatters(FormattingConversionService conversionService) {
                if (this.formatters != null) {
                        for (Object formatter : this.formatters) {
                                if (formatter instanceof Formatter<?>) {
                                        conversionService.addFormatter((Formatter<?>) formatter);
                                }
                                else if (formatter instanceof AnnotationFormatterFactory<?>) {
                                        conversionService.addFormatterForFieldAnnotation((AnnotationFormatterFactory<?>) formatter);
                                }
                                else {
                                        throw new IllegalArgumentException(
                                                        "Custom formatters must be implementations of Formatter or AnnotationFormatterFactory");
                                }
                        }
                }
                if (this.formatterRegistrars != null) {
                        for (FormatterRegistrar registrar : this.formatterRegistrars) {
                                registrar.registerFormatters(conversionService);
                        }
                }
        }


        @Override
        @Nullable
        public FormattingConversionService getObject() {
                return this.conversionService;
        }

        @Override
        public Class<? extends FormattingConversionService> getObjectType() {
                return FormattingConversionService.class;
        }

        @Override
        public boolean isSingleton() {
                return true;
        }

}