add javadoc and make methods more robust

src/main/java/gov/hhs/aspr/ms/util/resourcehelper/ResourceError.java

@@ -3,7 +3,9 @@
 import gov.hhs.aspr.ms.util.errors.ContractError;
 
 public enum ResourceError implements ContractError {
-    UNKNOWN_FILE("Provided file does not exist");
+    UNKNOWN_FILE("Provided file does not exist"),
+    FILE_PATH_IS_DIRECTORY("The provided file path points to a directory and not a file"),
+    DIRECTORY_PATH_IS_FILE("The provided directory path points to a file and not a directory");
 
     private final String description;
 

src/main/java/gov/hhs/aspr/ms/util/resourcehelper/ResourceHelper.java

@@ -5,83 +5,270 @@
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
-import java.nio.file.Files;
 import java.nio.file.Path;
 
 import gov.hhs.aspr.ms.util.errors.ContractException;
 
+/**
+ * ResourceHelper is a class designed to solve the issue that sometimes arises
+ * when running UnitTests and using files from the resources directory within
+ * the src/test folder.
+ * <p>
+ * The issue is that the relative path to the resource folder is dependant on
+ * what folder you are executing the test from. This can vary from IDE to IDE
+ * and even from where you run the maven command if using maven to run the unit
+ * tests.
+ * <p>
+ * This solves the issues by obtaining an absolute reference to the resource
+ * directory by using the class loader and an empty resource.
+ * <p>
+ * In addition to the above, this class also provides convience methods to
+ * validate file paths and directory paths, and create directories and files.
+ */
 public class ResourceHelper {
 
-    private ResourceHelper() {
-    }
-
+    /**
+     * Given a class ref, uses the class loader from the classref and an empty
+     * resource name to obtain a URI and then creates and returns a Path from that
+     * URI. This path will be an absolute path and not a relative path. Because it
+     * uses the classloader, it no longer matters from where this method gets called
+     * with respect to the java command used to call it.
+     * <p>
+     * This solves the problem of unit tests that use files from the
+     * src/test/resources sometimes failing because of the directory from which the
+     * test was executed.
+     * 
+     * @throws RuntimeException if the url provided by the classloader cannot be
+     *                              converted to a valid URI. Note that the
+     *                              RuntimeException wraps the thrown
+     *                              {@link URISyntaxException}
+     */
     public static Path getResourceDir(Class<?> classRef) {
         return Path.of(getURI(classRef.getClassLoader().getResource("")));
     }
 
-    protected static URI getURI(URL url) {
-        try {
-            return url.toURI();
-        } catch (URISyntaxException e) {
-            throw new RuntimeException(e);
+    /**
+     * Given a path, creates the directory. This internally calls
+     * dirPath.toFile().mkdirs().
+     */
+    public static Path createDirectory(Path dirPath) {
+        if (dirPath.toFile().exists()) {
+            return dirPath;
         }
-    }
 
-    public static Path makeOutputDir(Path dirPath) {
         dirPath.toFile().mkdirs();
 
         return dirPath;
     }
 
-    public static Path makeOutputDir(Path basepath, String subDir) {
-        Path dirPath = basepath.resolve(subDir);
+    /**
+     * Given a string that is a valid path, creates the directory.
+     * <p>
+     * calls {@link ResourceHelper#createDirectory(Path)}
+     */
+    public static Path createDirectory(String directory) {
+        Path dirPath = Path.of(directory);
+
+        return createDirectory(dirPath);
+    }
+
+    /**
+     * Given a base directory path and a sub directory, resolves the sub directory
+     * against the base path and calls {@link ResourceHelper#createDirectory(Path)}
+     * <p>
+     * returns the resolved path
+     */
+    public static Path createDirectory(Path baseDirPath, String subDir) {
+        Path dirPath = baseDirPath.resolve(subDir);
+
+        return createDirectory(dirPath);
+    }
+
+    /**
+     * Given a base directory and a sub directory, resolves the sub directory
+     * against the base path and calls {@link ResourceHelper#createDirectory(Path)}
+     * <p>
+     * returns the resolved path
+     */
+    public static Path createDirectory(String baseDir, String subDir) {
+        Path dirPath = Path.of(baseDir, subDir);
+
+        return createDirectory(dirPath);
+    }
+
+    /**
+     * Given a directory path and a file name, creates a file with the given name in
+     * the given directory.
+     * 
+     * @throws RuntimeException if the file cannot be created. Note that the
+     *                              RuntimeException wraps the thrown
+     *                              {@link IOException}
+     */
+    public static void createFile(Path directory, String fileName) {
+
+        File file = directory.resolve(fileName).toFile();
+
+        if (file.exists()) {
+            return;
+        }
+
+        _createFile(file);
+    }
+
+    /**
+     * Given a directory path and a file name, creates a file with the given name in
+     * the given directory.
+     * <p>
+     * Deletes the file if it exists before creating the file.
+     * 
+     * @throws RuntimeException if the file cannot be created. Note that the
+     *                              RuntimeException wraps the thrown
+     *                              {@link IOException}
+     */
+    public static void createNewFile(Path directory, String fileName) {
+
+        File file = directory.resolve(fileName).toFile();
+
+        if (file.exists()) {
+            file.delete();
+        }
+
+        _createFile(file);
+    }
+
+    /**
+     * Given a file path, validates that the file exists.
+     * <p>
+     * calls {@link ResourceHelper#validateFilePath(Path)}
+     * 
+     * @throws ContractException {@link ResourceError#FILE_PATH_IS_DIRECTORY} if the
+     *                               file path refers to a directory
+     */
+    public static Path validateFile(String file) {
+        Path filePath = Path.of(file);
 
-        return makeOutputDir(dirPath);
+        validateFile(filePath);
+
+        return filePath;
     }
 
-    public static void createOutputFile(Path filePath, String fileName) {
+    /**
+     * Given a file path, validates that the file exists.
+     * 
+     * @throws ContractException {@link ResourceError#FILE_PATH_IS_DIRECTORY} if the
+     *                               file path refers to a directory
+     */
+    public static Path validateFile(Path filePath) {
+        File file = filePath.toFile();
 
-        File isAfile = filePath.resolve(fileName).toFile();
+        if (file.isDirectory()) {
+            throw new ContractException(ResourceError.FILE_PATH_IS_DIRECTORY);
+        }
 
-        if (isAfile.exists()) {
-            isAfile.delete();
+        if (!file.exists()) {
+            throw new ContractException(ResourceError.UNKNOWN_FILE);
         }
 
-        createFile(isAfile);
+        return filePath;
+    }
+
+    /**
+     * Given a file path, validates that the file exists.
+     * <p>
+     * calls {@link ResourceHelper#validateFilePath(Path)}
+     * 
+     * @throws ContractException {@link ResourceError#FILE_PATH_IS_DIRECTORY} if the
+     *                               file path refers to a directory
+     */
+    public static Path validateFilePath(String file) {
+        Path filePath = Path.of(file);
+
+        validateFilePath(filePath);
+
+        return filePath;
     }
 
-    public static Path validatePath(String path, boolean isOutput) {
-        Path maybePath = Path.of(path);
-        File maybeFile = maybePath.toFile();
+    /**
+     * Given a file path, validates that the file exists.
+     * 
+     * @throws ContractException {@link ResourceError#FILE_PATH_IS_DIRECTORY} if the
+     *                               file path refers to a directory
+     */
+    public static Path validateFilePath(Path filePath) {
+        File file = filePath.toFile();
 
-        boolean isDirectory = maybeFile.isDirectory();
-        boolean isFile = maybeFile.isFile();
+        if (file.isDirectory()) {
+            throw new ContractException(ResourceError.FILE_PATH_IS_DIRECTORY);
+        }
 
-        // if the given string corresponds to a file that exists, return path
-        if (isFile) {
-            return maybePath;
+        if (!file.exists()) {
+            validateDirectoryPath(filePath.getParent());
         }
 
-        // if file does not exist, ensure the path is not a directory and that the
-        // parent directory of the outputFile exists.
-        if (isOutput && !isDirectory) {
-            Path parentPath = maybePath.getParent();
+        return filePath;
+    }
+
+    /**
+     * Given a directory path, validates that the directory exists.
+     * <p>
+     * calls {@link ResourceHelper#validateDirectoryPath(Path)}
+     * 
+     * @throws ContractException {@link ResourceError#DIRECTORY_PATH_IS_FILE} if the
+     *                               directory path refers to a file
+     */
+    public static Path validateDirectoryPath(String directory) {
+        Path maybePath = Path.of(directory);
+
+        validateDirectoryPath(maybePath);
+
+        return maybePath;
+    }
+
+    /**
+     * Given a directory path, validates that the directory exists.
+     * 
+     * @throws ContractException {@link ResourceError#DIRECTORY_PATH_IS_FILE} if the
+     *                               directory path refers to a file
+     */
+    public static Path validateDirectoryPath(Path directoryPath) {
+        File maybeFile = directoryPath.toFile();
+
+        if (maybeFile.isFile()) {
+            throw new ContractException(ResourceError.DIRECTORY_PATH_IS_FILE);
+        }
 
-            if (Files.exists(parentPath)) {
-                return maybePath;
-            }
+        if (!maybeFile.exists()) {
+            createDirectory(directoryPath);
         }
 
-        // otherwise throw an exception
-        throw new ContractException(ResourceError.UNKNOWN_FILE, path);
+        return directoryPath;
+    }
+
+    /**
+     * Given a url, converts it to a URI
+     */
+    protected static URI getURI(URL url) {
+        try {
+            return url.toURI();
+        } catch (URISyntaxException e) {
+            throw new RuntimeException(e);
+        }
     }
 
-    protected static void createFile(File file) {
+    /**
+     * Given a file, attempts to create the file
+     * 
+     * package access for testing
+     */
+    static void _createFile(File file) {
         try {
             file.createNewFile();
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
     }
 
+    private ResourceHelper() {
+    }
+
 }