Restored two helper classes from legacy module

Author: jekh

browsermob-dist/src/main/java/net/lightbody/bmp/exception/JettyException.java

@@ -0,0 +1,25 @@
+package net.lightbody.bmp.exception;
+
+/**
+ * A wrapper for exceptions coming from Jetty methods that throw Exception,
+ * rather than a useful Exception subclass.
+ */
+public class JettyException extends RuntimeException {
+	private static final long serialVersionUID = 8125833642102189196L;
+
+	public JettyException() {
+	}
+
+	public JettyException(String message) {
+		super(message);
+	}
+
+	public JettyException(Throwable cause) {
+		super(cause);
+	}
+
+	public JettyException(String message, Throwable cause) {
+		super(message, cause);
+	}
+
+}

browsermob-dist/src/main/java/net/lightbody/bmp/util/DeleteDirectoryTask.java

@@ -0,0 +1,60 @@
+package net.lightbody.bmp.util;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
+
+/**
+ * A Runnable that deletes the specified directory. Useful as a shutdown hook.
+ */
+public class DeleteDirectoryTask implements Runnable {
+    // the static final logger is in this static inner class to allow the logger initialization code to use DeleteDirectoryTask
+    // without prematurely initializing the logger when loading this class. since the 'log' field is in a static inner class, it will
+    // only be initialized when it is actually used, instead of when the classloader loads the DeleteDirectoryTask class.
+    private static class LogHolder {
+        private static final Logger log = LoggerFactory.getLogger(DeleteDirectoryTask.class);
+    }
+
+    private final Path directory;
+
+    public DeleteDirectoryTask(Path directory) {
+        this.directory = directory;
+    }
+
+    @Override
+    public void run() {
+        try {
+            Files.walkFileTree(directory, new SimpleFileVisitor<Path>() {
+                @Override
+                public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
+                    try {
+                        Files.delete(file);
+                    } catch (IOException e) {
+                        LogHolder.log.warn("Unable to delete file or directory", e);
+                    }
+
+                    return FileVisitResult.CONTINUE;
+                }
+
+                @Override
+                public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
+                    try {
+                        Files.delete(dir);
+                    } catch (IOException e) {
+                        LogHolder.log.warn("Unable to delete file or directory", e);
+                    }
+
+                    return FileVisitResult.CONTINUE;
+                }
+            });
+        } catch (IOException e) {
+            LogHolder.log.warn("Unable to delete file or directory", e);
+        }
+    }
+}