feat: add download script

src/Download.java

+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
+
+public class Download {
+
+	private static Logger log = java.util.logging.Logger.getLogger(Download.class.getName());
+	public static final List<String> skipNames = List.of("target", ".settings", ".project", ".classpath");
+	public static final String TAR_GZ_PATTERN = ".*\\.tar\\.gz";
+
+	public static void main(String[] args) {
+		try {
+			if (args.length < 2) {
+				printUsage();
+			} else {
+				boolean unzip = false;
+				int cutoff = 0;
+				String url = null;
+				String destPath = null;
+				for (String arg : args) {
+					if ("-unzip".equalsIgnoreCase(arg)) {
+						unzip = true;
+					} else if (arg.toLowerCase().startsWith("-cutoff:")) {
+						String[] parts = arg.split(":");
+						if (parts.length > 1) {
+							try {
+								cutoff = Integer.parseInt(parts[1]);
+							} catch (Exception e) {
+								log.log(Level.WARNING, "Cannot cunvert cutoff count into integer.", e);
+							}
+						}
+					} else if (url == null) {
+						url = arg;
+					} else if (destPath == null) {
+						destPath = arg;
+					} else {
+						log.log(Level.WARNING, "Uknown argument '{}'.", arg);
+					}
+				}
+				if (url != null && destPath != null) {
+					download(url, Paths.get(destPath), unzip, cutoff);
+				} else {
+					printUsage();
+				}
+			}
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
+
+	private static void printUsage() {
+		log.info(
+				"Usage:\n  java [--source 21 --enable-preview] FixDirStructure.java [-unzip] [-cutoff:n] <url> <destFile> ");
+	}
+
+	private static void download(String urlString, Path destPath, boolean unzip, int cutoffParrent) {
+		try (InputStream inputStream = new URL(urlString).openStream()) {
+			if (unzip) {
+				destPath.toFile().mkdirs();
+				extractZipStream(inputStream, destPath, cutoffParrent);
+			} else {
+				Path parent = destPath.getParent();
+				if(parent != null) {
+					parent.toFile().mkdirs();
+				}
+				Files.copy(inputStream, destPath, StandardCopyOption.REPLACE_EXISTING);
+			}
+		} catch (MalformedURLException ex) {
+			log.log(Level.SEVERE, "Cannot connect to git", ex);
+		} catch (IOException ex) {
+			log.log(Level.SEVERE, "Cannot douwnload and extract multi project evaluator", ex);
+		}
+	}
+
+	private static final int BUFFER_SIZE = 4096;
+
+	/**
+	 * Extracts a zip file specified by the zipFilePath to a directory specified by
+	 * destDirectory (will be created if does not exists)
+	 *
+	 * @param zipFilePath
+	 * @throws IOException
+	 */
+	public static void unzip(File zipFilePath, Path destDir) throws IOException {
+		if (!destDir.toFile().exists()) {
+			destDir.toFile().mkdir();
+		}
+		try (InputStream in = new FileInputStream(zipFilePath)) {
+			extractZipStream(in, destDir);
+		}
+	}
+
+	private static void extractZipStream(InputStream zipInputStream, Path destDir) throws IOException {
+		extractZipStream(zipInputStream, destDir, 0);
+	}
+
+	private static void extractZipStream(InputStream zipInputStream, Path destDir, int cutoffParent)
+			throws FileNotFoundException, IOException {
+		ZipInputStream zipIn = new ZipInputStream(zipInputStream);
+		ZipEntry entry = zipIn.getNextEntry();
+		// iterates over entries in the zip file
+		while (entry != null) {
+			Path entryPath = Paths.get(entry.getName());
+			if (entry.isDirectory() && entryPath.getNameCount() <= cutoffParent) {
+				entryPath = Paths.get("");
+			} else if (!entry.isDirectory() && entryPath.getNameCount() <= cutoffParent) {
+				entryPath = entryPath.getFileName();
+			} else {
+				entryPath = entryPath.subpath(cutoffParent, entryPath.getNameCount());
+			}
+			Path filePath = destDir.resolve(entryPath);
+			if (!entry.isDirectory()) {
+				// if the entry is a file, extracts it
+				extractFile(zipIn, filePath);
+			} else {
+				// if the entry is a directory, make the directory
+				File dir = filePath.toFile();
+				dir.mkdirs();
+			}
+			zipIn.closeEntry();
+			entry = zipIn.getNextEntry();
+		}
+		zipIn.close();
+	}
+
+	/**
+	 * Extracts a zip entry (file entry)
+	 *
+	 * @param zipIn
+	 * @param filePath
+	 * @throws IOException
+	 */
+	private static void extractFile(ZipInputStream zipIn, Path filePath) throws IOException {
+		try (BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(filePath.toFile()))) {
+			byte[] bytesIn = new byte[BUFFER_SIZE];
+			int read = 0;
+			while ((read = zipIn.read(bytesIn)) != -1) {
+				bos.write(bytesIn, 0, read);
+			}
+		}
+	}
+
+}

src/FixDirStructure.java

@@ -57,7 +57,7 @@ import org.xml.sax.SAXException;
 public class FixDirStructure {
 
 	private static Logger log = java.util.logging.Logger.getLogger(FixDirStructure.class.getName());
-	public static final List<String> skipNames = List.of("target", ".settings", ".project", ".classpath");
+	public static final List<String> skipNames = List.of("target", ".settings", ".project", ".classpath", ".kelvin-utils");
 	public static final String TAR_GZ_PATTERN = ".*\\.tar\\.gz";
 
 	public static void main(String[] args) {