Spring Framework - AnnotationFormatterFactory Examples

package com.logicbig.example;

import org.springframework.beans.MutablePropertyValues;
import org.springframework.format.support.DefaultFormattingConversionService;
import org.springframework.validation.BindingResult;
import org.springframework.validation.DataBinder;

import java.text.DateFormat;
import java.util.Locale;

public class CustomFormatAnnotationExample {

    public static void main(String[] args) {

        DefaultFormattingConversionService service =
                new DefaultFormattingConversionService();
        service.addFormatterForFieldAnnotation(
                new LocaleFormatAnnotationFormatterFactory());

        MyBean bean = new MyBean();
        DataBinder dataBinder = new DataBinder(bean);
        dataBinder.setConversionService(service);

        MutablePropertyValues mpv = new MutablePropertyValues();
        mpv.add("myLocale", "CYP");

        dataBinder.bind(mpv);

        Object target = dataBinder.getTarget();
        System.out.println(target);

        BindingResult bindingResult = dataBinder.getBindingResult();
        System.out.println(bindingResult);
        System.out.println(bean.getMyLocale().getDisplayName());
    }
}

package com.logicbig.example;


import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;


@Target({ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
public @interface LocaleFormat {
    LocaleStyle style() default LocaleStyle.CountryDisplayName;
}

package com.logicbig.example;

public enum LocaleStyle {
    CountryDisplayName,
    ISO3Country,
    ISO3Language;
}

package com.logicbig.example;

import org.springframework.format.Formatter;

import java.text.ParseException;
import java.util.Arrays;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.Optional;

public class LocaleFormatter implements Formatter<Locale> {
    private LocaleStyle localeStyle;

    public LocaleStyle getLocaleStyle () {
        return localeStyle;
    }

    public void setLocaleStyle (
            LocaleStyle localeStyle) {
        this.localeStyle = localeStyle;
    }

    @Override
    public Locale parse (String text, Locale locale) throws ParseException {
        Optional<Locale> o = Arrays.stream(Locale.getAvailableLocales()).parallel()
                .filter(l -> this.localeByStylePredicate(l, text))
                .findAny();
        if (o.isPresent()) {
            return o.get();
        }
        return null;
    }

    @Override
    public String print (Locale object, Locale locale) {
        switch (localeStyle) {
            case CountryDisplayName:
                return object.getDisplayCountry();
            case ISO3Country:
                return object.getISO3Country();
            case ISO3Language:
                return object.getISO3Language();
        }
        return object.toString();
    }

    private boolean localeByStylePredicate (Locale locale, String text) {
        try {
            switch (localeStyle) {
                case CountryDisplayName:
                    return locale.getDisplayCountry().equalsIgnoreCase(text);
                case ISO3Country:
                    return locale.getISO3Country().equalsIgnoreCase(text);
                case ISO3Language:
                    return locale.getISO3Language().equalsIgnoreCase(text);
            }
        } catch (MissingResourceException e) {
            //ignore;
        }
        return false;
    }
}

package com.logicbig.example;

import org.springframework.format.AnnotationFormatterFactory;
import org.springframework.format.Formatter;
import org.springframework.format.Parser;
import org.springframework.format.Printer;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Locale;
import java.util.Set;

public class LocaleFormatAnnotationFormatterFactory implements
        AnnotationFormatterFactory<LocaleFormat> {

    @Override
    public Set<Class<?>> getFieldTypes() {
        return new HashSet<>(Arrays.asList(Locale.class));
    }

    @Override
    public Printer<?> getPrinter(LocaleFormat annotation, Class<?> fieldType) {
        return getLocaleFormatter(annotation, fieldType);
    }

    @Override
    public Parser<?> getParser(LocaleFormat annotation,
                               Class<?> fieldType) {
        return getLocaleFormatter(annotation, fieldType);
    }

    private Formatter<?> getLocaleFormatter(LocaleFormat annotation, Class<?> fieldType) {
        LocaleFormatter lf = new LocaleFormatter();
        lf.setLocaleStyle(annotation.style());
        return lf;
    }
}

package com.logicbig.example;

import java.util.Locale;

public class MyBean {
    @LocaleFormat(style = LocaleStyle.ISO3Country)
    private Locale myLocale;

    public Locale getMyLocale() {
        return myLocale;
    }

    public void setMyLocale(Locale myLocale) {
        this.myLocale = myLocale;
    }

    @Override
    public String toString() {
        return "MyBean{" +
                "myLocale=" + myLocale +
                '}';
    }
}