src/main/java/io/mifos/core/lang/DateConverter.java

/*
 * Copyright 2018 The Apache Software Foundation
 *
 * 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
 *
 *    http://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 io.mifos.core.lang;

import org.springframework.util.Assert;

import javax.annotation.Nonnull;
import java.time.*;
import java.time.format.DateTimeFormatter;
import java.util.Date;

public interface DateConverter {
  @Nonnull
  static Long toEpochMillis(@Nonnull final LocalDateTime localDateTime) {
    Assert.notNull(localDateTime, "LocalDateTime must be given.");
    return localDateTime.toInstant(ZoneOffset.UTC).toEpochMilli();
  }

  @Nonnull
  static Long toEpochDay(@Nonnull final LocalDate localDate) {
    Assert.notNull(localDate, "LocalDate must be given.");
    return localDate.toEpochDay();
  }

  @Nonnull
  static LocalDateTime fromEpochMillis(@Nonnull final Long epochMillis) {
    Assert.notNull(epochMillis, "Epoch milliseconds must be given.");
    return LocalDateTime.from(Instant.ofEpochMilli(epochMillis).atZone(ZoneOffset.UTC));
  }

  @Nonnull
  static String toIsoString(@Nonnull final Date date) {
    return toIsoString(LocalDateTime.ofInstant(date.toInstant(), ZoneId.of("UTC")));
  }

  @Nonnull
  static String toIsoString(@Nonnull final LocalDateTime localDateTime) {
    Assert.notNull(localDateTime, "LocalDateTime must be given.");
    return localDateTime.format(DateTimeFormatter.ISO_DATE_TIME) + "Z";
  }

  @Nonnull
  static LocalDateTime fromIsoString(@Nonnull final String isoDateTimeString) {
    Assert.notNull(isoDateTimeString, "ISO date time must be given.");
    return LocalDateTime.from(Instant.parse(isoDateTimeString).atZone(ZoneOffset.UTC));
  }

  @Nonnull
  static LocalDate dateFromIsoString(@Nonnull final String isoDateString) {
    Assert.notNull(isoDateString, "ISO date time must be given.");
    final int zIndex = isoDateString.indexOf("Z");
    final String shortenedString = isoDateString.substring(0, zIndex);
    return LocalDate.from(DateTimeFormatter.ISO_LOCAL_DATE.parse(shortenedString));
  }

  @Nonnull
  static String toIsoString(@Nonnull final LocalDate localDate) {
    Assert.notNull(localDate, "LocalDateTime must be given.");
    return localDate.format(DateTimeFormatter.ISO_DATE) + "Z";
  }

  @Nonnull
  static LocalDate toLocalDate(@Nonnull final LocalDateTime localDateTime) {
    Assert.notNull(localDateTime, "LocalDateTime must be given.");
    return localDateTime.toLocalDate();
  }
}