ClassPath Class — spring-boot Architecture

Source Code

build-plugin/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/ClassPath.java lines 49–149

final class ClassPath {

	private static final Collector<CharSequence, ?, String> JOIN_BY_PATH_SEPARATOR = Collectors
		.joining(File.pathSeparator);

	private final boolean preferArgFile;

	private final String path;

	private ClassPath(boolean preferArgFile, String path) {
		this.preferArgFile = preferArgFile;
		this.path = path;
	}

	/**
	 * Return the args to append to a java command line call (including {@code -cp}).
	 * @param allowArgFile if an arg file can be used
	 * @return the command line arguments
	 */
	List<String> args(boolean allowArgFile) {
		return (!this.path.isEmpty()) ? List.of("-cp", classPathArg(allowArgFile)) : Collections.emptyList();
	}

	private String classPathArg(boolean allowArgFile) {
		if (this.preferArgFile && allowArgFile) {
			try {
				return "@" + createArgFile();
			}
			catch (IOException ex) {
				return this.path;
			}
		}
		return this.path;
	}

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

	private Path createArgFile() throws IOException {
		Path argFile = Files.createTempFile("spring-boot-", ".argfile");
		argFile.toFile().deleteOnExit();
		Files.writeString(argFile, "\"" + this.path.replace("\\", "\\\\") + "\"", charset());
		return argFile;
	}

	private Charset charset() {
		try {
			String nativeEncoding = System.getProperty("native.encoding");
			return (nativeEncoding != null) ? Charset.forName(nativeEncoding) : Charset.defaultCharset();
		}
		catch (UnsupportedCharsetException ex) {
			return Charset.defaultCharset();
		}
	}

	/**
	 * Factory method to create a {@link ClassPath} of the given URLs.
	 * @param urls the class path URLs
	 * @return a new {@link ClassPath} instance
	 */
	static ClassPath of(URL... urls) {
		return of(Arrays.asList(urls));
	}

	/**
	 * Factory method to create a {@link ClassPath} of the given URLs.
	 * @param urls the class path URLs
	 * @return a new {@link ClassPath} instance
	 */
	static ClassPath of(List<URL> urls) {
		return of(System::getProperty, urls);
	}

	/**
	 * Factory method to create a {@link ClassPath} of the given URLs.
	 * @param getSystemProperty {@link UnaryOperator} allowing access to system properties
	 * @param urls the class path URLs
	 * @return a new {@link ClassPath} instance
	 */
	static ClassPath of(UnaryOperator<@Nullable String> getSystemProperty, List<URL> urls) {
		boolean preferArgFile = urls.size() > 1 && isWindows(getSystemProperty);
		return new ClassPath(preferArgFile, urls.stream().map(ClassPath::toPathString).collect(JOIN_BY_PATH_SEPARATOR));
	}

	private static boolean isWindows(UnaryOperator<@Nullable String> getSystemProperty) {
		String os = getSystemProperty.apply("os.name");
		return StringUtils.hasText(os) && os.toLowerCase(Locale.ROOT).contains("win");
	}

	private static String toPathString(URL url) {
		try {
			return Paths.get(url.toURI()).toString();
		}
		catch (URISyntaxException ex) {
			throw new IllegalArgumentException(ex);
		}
	}

}