Time & Date Operations

/**
 * Time unit conversion utilities
 */
public class TimeUtil {
    /**
     * Converts time unit to milliseconds
     * @param timeUnit - TimeUnit to convert
     * @return Milliseconds for one unit of the specified time unit
     */
    public static long oneTimeUnitMillisecond(TimeUnit timeUnit);
    
    /**
     * Gets next rounded timestamp for the given time unit
     * @param timeUnit - Time unit for rounding
     * @param start - Starting timestamp
     * @return Next timestamp rounded to the time unit boundary
     */
    public static long nextStartTimestamp(TimeUnit timeUnit, long start);
}

/**
 * ISO 8601 date formatting and parsing
 */
public class DateUtil {
    /**
     * Formats date as ISO 8601 string
     * @param date - Instant to format
     * @return ISO 8601 formatted date string
     */
    public static String formatIso8601Date(Instant date);
    
    /**
     * Parses ISO 8601 date string to Instant
     * @param dateString - ISO 8601 date string
     * @return Parsed Instant
     */
    public static Instant parseIso8601Date(String dateString);
    
    /**
     * Parses ISO 8601 date string to milliseconds
     * @param dateString - ISO 8601 date string  
     * @return Milliseconds since epoch
     */
    public static long parseIso8601DateToMillis(String dateString);
}

import com.networknt.utility.TimeUtil;
import com.networknt.utility.DateUtil;
import java.time.Instant;
import java.util.concurrent.TimeUnit;

// Time unit conversions
long secondInMillis = TimeUtil.oneTimeUnitMillisecond(TimeUnit.SECONDS); // 1000
long minuteInMillis = TimeUtil.oneTimeUnitMillisecond(TimeUnit.MINUTES); // 60000
long hourInMillis = TimeUtil.oneTimeUnitMillisecond(TimeUnit.HOURS); // 3600000

// Timestamp rounding
long currentTime = System.currentTimeMillis();
long nextMinute = TimeUtil.nextStartTimestamp(TimeUnit.MINUTES, currentTime);
long nextHour = TimeUtil.nextStartTimestamp(TimeUnit.HOURS, currentTime);

// ISO 8601 date formatting
Instant now = Instant.now();
String isoDate = DateUtil.formatIso8601Date(now);
// Result: "2023-12-25T10:30:45.123Z"

// ISO 8601 date parsing
String dateString = "2023-12-25T10:30:45.123Z";
Instant parsed = DateUtil.parseIso8601Date(dateString);
long millis = DateUtil.parseIso8601DateToMillis(dateString);

// Microservice timestamp coordination
public class EventLogger {
    public void logEvent(String event) {
        Instant timestamp = Instant.now();
        String isoTimestamp = DateUtil.formatIso8601Date(timestamp);
        System.out.println(isoTimestamp + " - " + event);
    }
    
    public void scheduleNextExecution(TimeUnit interval, long currentTime) {
        long nextExecution = TimeUtil.nextStartTimestamp(interval, currentTime);
        // Schedule task at nextExecution
    }
}

// Time-based cache expiration
public class TimeBasedCache {
    private final long ttlMillis;
    
    public TimeBasedCache(long amount, TimeUnit unit) {
        this.ttlMillis = amount * TimeUtil.oneTimeUnitMillisecond(unit);
    }
    
    public boolean isExpired(long creationTime) {
        return System.currentTimeMillis() - creationTime > ttlMillis;
    }
}