icu_generators_2_pattern.java

/*

    PHP <8.1 does not support

    https://unicode-org.github.io/icu/userguide/format_parse/datetime/index#datetimepatterngenerator

 */
package com.computermind.sandbox.icu;

import com.ibm.icu.text.DateTimePatternGenerator;
import com.ibm.icu.text.SimpleDateFormat;
import com.ibm.icu.util.TimeZone;
import com.ibm.icu.util.ULocale;

import java.util.Date;
import java.util.List;

import static java.util.Arrays.asList;

public class Test {
    public static void main(String... args) {

        // TODO config here locales and generators
        final List<String> locales = asList("es", "en-US");
        final List<String> icuGenerators = asList("MMMMdjmm", "yMMMM", "M/d", "EEEEMMMMdy");

        final Date sample = new Date(2021 - 1900, 7, 25, 9, 31, 7);
        System.out.printf("  const ICU_GENERATOR_2_PATTERN = [%n");
        for (final String generator : icuGenerators) {
            System.out.printf("    \"%s\" => [%n", generator);
            for (final String locale : locales) {
                final ULocale ulocale = ULocale.forLanguageTag(locale);
                final DateTimePatternGenerator dtpg = DateTimePatternGenerator.getInstance(ulocale);
                final String pattern = dtpg.getBestPattern(generator);
                SimpleDateFormat format = new SimpleDateFormat(pattern, ulocale);
                format.setTimeZone(TimeZone.getDefault());
                System.out.printf("      \"%s\" => \"%s\", // %s%n", locale, pattern, format.format(sample));
            }
            System.out.printf("    ],%n");
        }
        System.out.printf("  ];%n");
    }
}