A utility that generates time-based UUIDs for uploaded files

UploadVersion.java

package com.example;

import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.time.Instant;
import java.util.UUID;

import com.github.f4b6a3.uuid.UuidCreator;

/**
 * A utility that generates time-based UUIDs for uploaded files.
 * 
 * The upload date is transformed into the UUID's timestamp.
 * 
 * The file name or URL is transformed into the UUID's node identifier.
 * 
 * This example is inspired on a real use case found here in GitHub.
 */
public final class UploadVersion {

	private UploadVersion() {
	}

	public static UUID getVersion(Instant date, String name) {
		final long node = getNameHash(name);
		return UuidCreator.getTimeBased(date, null, node);
	}

	private static long getNameHash(String name) {
		try {
			MessageDigest hasher = MessageDigest.getInstance("MD5");
			byte[] md5 = hasher.digest(name.getBytes(StandardCharsets.UTF_8));
			return ByteBuffer.wrap(md5).getLong();
		} catch (NoSuchAlgorithmException var3) {
			throw new InternalError("MD5 not supported", var3);
		}
	}

	public static void main(String[] args) {
		Instant date = Instant.now();
		String name = "My uploaded file.jpg";
		UUID uuid = UploadVersion.getVersion(date, name);
		System.out.println(uuid);
	}
}