VolumeName Class — spring-boot Architecture

Source Code

buildpack/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/type/VolumeName.java lines 35–144

public final class VolumeName {

	private final String value;

	private VolumeName(String value) {
		this.value = value;
	}

	@Override
	public boolean equals(@Nullable Object obj) {
		if (this == obj) {
			return true;
		}
		if (obj == null || getClass() != obj.getClass()) {
			return false;
		}
		return this.value.equals(((VolumeName) obj).value);
	}

	@Override
	public int hashCode() {
		return this.value.hashCode();
	}

	@Override
	public String toString() {
		return this.value;
	}

	/**
	 * Factory method to create a new {@link VolumeName} with a random name.
	 * @param prefix the prefix to use with the random name
	 * @return a randomly named volume
	 */
	public static VolumeName random(String prefix) {
		return random(prefix, 10);
	}

	/**
	 * Factory method to create a new {@link VolumeName} with a random name.
	 * @param prefix the prefix to use with the random name
	 * @param randomLength the number of chars in the random part of the name
	 * @return a randomly named volume reference
	 */
	public static VolumeName random(String prefix, int randomLength) {
		return of(RandomString.generate(prefix, randomLength));
	}

	/**
	 * Factory method to create a new {@link VolumeName} based on an object. The resulting
	 * name will be based off a SHA-256 digest of the given object's {@code toString()}
	 * method.
	 * @param <S> the source object type
	 * @param source the source object
	 * @param prefix the prefix to use with the volume name
	 * @param suffix the suffix to use with the volume name
	 * @param digestLength the number of chars in the digest part of the name
	 * @return a name based off the image reference
	 */
	public static <S> VolumeName basedOn(S source, String prefix, String suffix, int digestLength) {
		return basedOn(source, Object::toString, prefix, suffix, digestLength);
	}

	/**
	 * Factory method to create a new {@link VolumeName} based on an object. The resulting
	 * name will be based off a SHA-256 digest of the given object's name.
	 * @param <S> the source object type
	 * @param source the source object
	 * @param nameExtractor a method to extract the name of the object
	 * @param prefix the prefix to use with the volume name
	 * @param suffix the suffix to use with the volume name
	 * @param digestLength the number of chars in the digest part of the name
	 * @return a name based off the image reference
	 */
	public static <S> VolumeName basedOn(S source, Function<S, String> nameExtractor, String prefix, String suffix,
			int digestLength) {
		Assert.notNull(source, "'source' must not be null");
		Assert.notNull(nameExtractor, "'nameExtractor' must not be null");
		Assert.notNull(prefix, "'prefix' must not be null");
		Assert.notNull(suffix, "'suffix' must not be null");
		return of(prefix + getDigest(nameExtractor.apply(source), digestLength) + suffix);
	}

	private static String getDigest(String name, int length) {
		try {
			MessageDigest digest = MessageDigest.getInstance("sha-256");
			return asHexString(digest.digest(name.getBytes(StandardCharsets.UTF_8)), length);
		}
		catch (NoSuchAlgorithmException ex) {
			throw new IllegalStateException(ex);
		}
	}

	private static String asHexString(byte[] digest, int digestLength) {
		Assert.isTrue(digestLength <= digest.length,
				() -> "'digestLength' must be less than or equal to " + digest.length);
		return HexFormat.of().formatHex(digest, 0, digestLength);
	}

	/**
	 * Factory method to create a {@link VolumeName} with a specific value.
	 * @param value the volume reference value
	 * @return a new {@link VolumeName} instance
	 */
	public static VolumeName of(String value) {
		Assert.notNull(value, "'value' must not be null");
		return new VolumeName(value);
	}

}