org.apache.ace.obr/src/org/apache/ace/obr/storage/file/BundleFileStore.java - ace - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */
 package org.apache.ace.obr.storage.file;

 import java.io.BufferedInputStream;
 import java.io.Closeable;
 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.math.BigInteger;
 import java.nio.channels.FileChannel;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
 import java.util.Dictionary;
 import java.util.List;
 import java.util.Stack;

 import org.apache.ace.obr.metadata.MetadataGenerator;
 import org.apache.ace.obr.metadata.util.ResourceMetaData;
 import org.apache.ace.obr.storage.BundleStore;
 import org.apache.ace.obr.storage.OBRFileStoreConstants;
 import org.osgi.service.cm.ConfigurationException;
 import org.osgi.service.cm.ManagedService;
 import org.osgi.service.log.LogService;

 /**
  * This BundleStore retrieves the files from the file system. Via the Configurator the relative path is set, and all
  * bundles and the index.xml should be retrievable from that path (which will internally be converted to an
  * absolute path).
  */
 public class BundleFileStore implements BundleStore, ManagedService {
     private static final String REPOSITORY_XML = "index.xml";
     private static int BUFFER_SIZE = 8 * 1024;

     private final Object m_lock = new Object();
     // injected by dependencymanager
     private volatile MetadataGenerator m_metadata;
     private volatile LogService m_log;

     private volatile String m_dirChecksum;
     private volatile File m_dir;

     /**
      * Checks if the the directory was modified since we last checked. If so, the meta-data generator is called.
      *
      * @throws IOException
      *             If there is a problem synchronizing the meta-data.
      */
     public void synchronizeMetadata() throws IOException {
         synchronized (m_lock) {
             File dir = m_dir;

             if (m_dirChecksum == null || !m_dirChecksum.equals(getDirChecksum(dir))) {
                 m_metadata.generateMetadata(dir);
                 m_dirChecksum = getDirChecksum(dir);
             }
         }
     }

     public InputStream get(String fileName) throws IOException {
         if (REPOSITORY_XML.equals(fileName)) {
             synchronizeMetadata();
         }

         FileInputStream result = null;
         try {
             result = new FileInputStream(createFile(fileName));
         }
         catch (FileNotFoundException e) {
             // Resource does not exist; notify caller by returning null...
         }

         return result;
     }

     public String put(InputStream data, String fileName, boolean replace) throws IOException {
         if (fileName == null) {
             fileName = "";
         }
         File tempFile = downloadToTempFile(data);

         ResourceMetaData metaData = ResourceMetaData.getBundleMetaData(tempFile);
         if (metaData == null) {
             metaData = ResourceMetaData.getArtifactMetaData(fileName);
         }
         if (metaData == null) {
             tempFile.delete();
             throw new IOException("Not a valid bundle and no filename found (filename = " + fileName + ")");
         }

         File storeLocation = getResourceFile(metaData);
         if (storeLocation == null) {
             tempFile.delete();
             throw new IOException("Failed to store resource (filename = " + fileName + ")");
         }

         if (storeLocation.exists()) {
             if (replace || compare(storeLocation, tempFile)) {
                 m_log.log(LogService.LOG_DEBUG, "Exact same resource already existed in OBR (filename = " + fileName + ")");
             }
             else {
                 m_log.log(LogService.LOG_ERROR, "Different resource with same name already existed in OBR (filename = " + fileName + ")");
                 return null;
             }
         }

         moveFile(tempFile, storeLocation);

         String filePath = storeLocation.toURI().toString().substring(getWorkingDir().toURI().toString().length());
         if (filePath.startsWith("/")) {
             filePath = filePath.substring(1);
         }
         return filePath;
     }

     /** Compares the contents of two files, returns <code>true</code> if they're exactly the same. */
     private boolean compare(File first, File second) throws IOException {
         BufferedInputStream bis = new BufferedInputStream(new FileInputStream(first));
         BufferedInputStream bis2 = new BufferedInputStream(new FileInputStream(second));
         int b1, b2;
         try {
             do {
                 b1 = bis.read();
                 b2 = bis2.read();
                 if (b1 != b2) {
                     return false;
                 }
             }
             while (b1 != -1 && b2 != -1);
             return (b1 == b2);
         }
         finally {
             if (bis != null) {
                 try {
                     bis.close();
                 }
                 catch (IOException e) {
                 }
             }
             if (bis2 != null) {
                 try {
                     bis2.close();
                 }
                 catch (IOException e) {
                 }
             }
         }
     }

     public boolean remove(String fileName) throws IOException {
         File dir;
         synchronized (m_lock) {
             dir = m_dir;
         }

         File file = createFile(fileName);
         if (file.exists()) {
             if (file.delete()) {
                 // deleting empty parent dirs
                 while ((file = file.getParentFile()) != null && !file.equals(dir) && file.list().length == 0) {
                     file.delete();
                 }
                 return true;
             }
             else {
                 throw new IOException("Unable to delete file (" + file.getAbsolutePath() + ")");
             }
         }
         return false;
     }

     public void updated(Dictionary<String, ?> dict) throws ConfigurationException {
         if (dict != null) {
             String path = (String) dict.get(OBRFileStoreConstants.FILE_LOCATION_KEY);
             if (path == null) {
                 throw new ConfigurationException(OBRFileStoreConstants.FILE_LOCATION_KEY, "Missing property");
             }

             File newDir = new File(path);
             File curDir = getWorkingDir();

             if (!newDir.equals(curDir)) {
                 if (!newDir.exists()) {
                     newDir.mkdirs();
                 }
                 else if (!newDir.isDirectory()) {
                     throw new ConfigurationException(OBRFileStoreConstants.FILE_LOCATION_KEY, "Is not a directory: " + newDir);
                 }

                 synchronized (m_lock) {
                     m_dir = newDir;
                     m_dirChecksum = "";
                 }
             }
         }
     }

     /**
      * Called by dependencymanager upon start of this component.
      */
     protected void start() {
         try {
             synchronizeMetadata();
         }
         catch (IOException e) {
             m_log.log(LogService.LOG_ERROR, "Could not generate initial meta data for bundle repository");
         }
     }

     /**
      * Computes a magic checksum used to determine whether there where changes in the directory without actually looking
      * into the files or using observation.
      *
      * @param dir
      *            The directory
      * @return The checksum
      */
     private String getDirChecksum(File dir) {
         MessageDigest digest = null;
         try {
             digest = MessageDigest.getInstance("MD5");
         }
         catch (NoSuchAlgorithmException e) {
             // really should not happen
             m_log.log(LogService.LOG_WARNING, "Unable to get an MD5 digest. Metadata will refresh every ten minutes.", e);
             return "" + (System.currentTimeMillis() / 600000);
         }

         Stack<File> dirs = new Stack<>();
         dirs.push(dir);
         while (!dirs.isEmpty()) {
             File pwd = dirs.pop();
             for (File file : pwd.listFiles()) {
                 if (file.isDirectory()) {
                     dirs.push(file);
                     continue;
                 }
                 // basically we hash the filenames, but...
                 // include last-modified to detect touched files
                 // include length to work around last-modified rounding issues
                 String magic = file.getName() + file.length() + file.lastModified();
                 digest.update(magic.getBytes());
             }
         }
         String checksum = new BigInteger(digest.digest()).toString();
         return checksum;
     }

     /**
      * Downloads a given input stream to a temporary file.
      *
      * @param source
      *            the input stream to download;
      * @throws IOException
      *             in case of I/O problems.
      */
     private File downloadToTempFile(InputStream source) throws IOException {
         File tempFile = File.createTempFile("obr", ".tmp");
         FileOutputStream fos = null;
         try {
             fos = new FileOutputStream(tempFile);
             int read;
             byte[] buffer = new byte[BUFFER_SIZE];
             while ((read = source.read(buffer)) >= 0) {
                 fos.write(buffer, 0, read);
             }
             fos.flush();
             fos.close();
             return tempFile;
         }
         finally {
             closeQuietly(fos);
         }
     }

     /**
      * Encapsulated the store layout strategy by creating the resource file based on the provided meta-data.
      *
      * @param metaData
      *            the meta-data for the resource
      * @return the resource file
      * @throws IOException
      *             in case of I/O problems.
      */
     private File getResourceFile(ResourceMetaData metaData) throws IOException {
         File resourceDirectory = getWorkingDir();
         String[] dirs = split(metaData.getSymbolicName());
         for (int i = 0; i < (dirs.length - 1); i++) {
             String subDir = dirs[i];
             resourceDirectory = new File(resourceDirectory, subDir);
         }
         if (!resourceDirectory.exists() && !resourceDirectory.mkdirs()) {
             throw new IOException("Failed to create store directory");
         }

         String name = metaData.getSymbolicName();
         String version = metaData.getVersion();
         if (version != null && !version.equals("") && !version.equals("0.0.0")) {
             name += "-" + version;
         }
         String extension = metaData.getExtension();
         if (extension != null && !extension.equals("")) {
             name += "." + extension;
         }
         return new File(resourceDirectory, name);
     }

     /**
      * Splits a name into parts, breaking at all dots as long as what's behind the dot resembles a Java package name
      * (ie. it starts with a lowercase character).
      *
      * @param name
      *            the name to split
      * @return an array of parts
      */
     public static String[] split(String name) {
         List<String> result = new ArrayList<>();
         int startPos = 0;
         for (int i = 0; i < (name.length() - 1); i++) {
             if (name.charAt(i) == '.') {
                 if (Character.isLowerCase(name.charAt(i + 1))) {
                     result.add(name.substring(startPos, i));
                     i++;
                     startPos = i;
                 }
                 else {
                     break;
                 }
             }
         }
         result.add(name.substring(startPos));
         return result.toArray(new String[result.size()]);
     }

     /**
      * @return the working directory of this file store.
      */
     private File getWorkingDir() {
         synchronized (m_lock) {
             return m_dir;
         }
     }

     /**
      * Moves a given source file to a destination location, effectively resulting in a rename.
      *
      * @param source
      *            the source file to move;
      * @param dest
      *            the destination file to move the file to.
      * @return <code>true</code> if the move succeeded.
      * @throws IOException
      *             in case of I/O problems.
      */
     private boolean moveFile(File source, File dest) throws IOException {
         final int bufferSize = 1024 * 1024; // 1MB

         FileInputStream fis = null;
         FileOutputStream fos = null;
         FileChannel input = null;
         FileChannel output = null;

         try {
             fis = new FileInputStream(source);
             input = fis.getChannel();

             fos = new FileOutputStream(dest);
             output = fos.getChannel();

             long size = input.size();
             long pos = 0;
             while (pos < size) {
                 pos += output.transferFrom(input, pos, Math.min(size - pos, bufferSize));
             }
         }
         finally {
             closeQuietly(fos);
             closeQuietly(fis);
             closeQuietly(output);
             closeQuietly(input);
         }

         if (source.length() != dest.length()) {
             throw new IOException("Failed to move file! Not all contents from '" + source + "' copied to '" + dest + "'!");
         }

         dest.setLastModified(source.lastModified());

         if (!source.delete()) {
             dest.delete();
             throw new IOException("Failed to move file! Source file (" + source + ") locked?");
         }

         return true;
     }

     /**
      * Safely closes a given resource, ignoring any I/O exceptions that might occur by this.
      *
      * @param resource
      *            the resource to close, can be <code>null</code>.
      */
     private void closeQuietly(Closeable resource) {
         try {
             if (resource != null) {
                 resource.close();
             }
         }
         catch (IOException e) {
             // Ignored...
         }
     }

     /**
      * Creates a {@link File} object with the given file name in the current working directory.
      *
      * @param fileName
      *            the name of the file.
      * @return a {@link File} object, never <code>null</code>.
      * @see #getWorkingDir()
      */
     private File createFile(String fileName) {
         return new File(getWorkingDir(), fileName);
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*/
	package org.apache.ace.obr.storage.file;

	import java.io.BufferedInputStream;
	import java.io.Closeable;
	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.math.BigInteger;
	import java.nio.channels.FileChannel;
	import java.security.MessageDigest;
	import java.security.NoSuchAlgorithmException;
	import java.util.ArrayList;
	import java.util.Dictionary;
	import java.util.List;
	import java.util.Stack;

	import org.apache.ace.obr.metadata.MetadataGenerator;
	import org.apache.ace.obr.metadata.util.ResourceMetaData;
	import org.apache.ace.obr.storage.BundleStore;
	import org.apache.ace.obr.storage.OBRFileStoreConstants;
	import org.osgi.service.cm.ConfigurationException;
	import org.osgi.service.cm.ManagedService;
	import org.osgi.service.log.LogService;

	/**
	* This BundleStore retrieves the files from the file system. Via the Configurator the relative path is set, and all
	* bundles and the index.xml should be retrievable from that path (which will internally be converted to an
	* absolute path).
	*/
	public class BundleFileStore implements BundleStore, ManagedService {
	private static final String REPOSITORY_XML = "index.xml";
	private static int BUFFER_SIZE = 8 * 1024;

	private final Object m_lock = new Object();
	// injected by dependencymanager
	private volatile MetadataGenerator m_metadata;
	private volatile LogService m_log;

	private volatile String m_dirChecksum;
	private volatile File m_dir;

	/**
	* Checks if the the directory was modified since we last checked. If so, the meta-data generator is called.
	*
	* @throws IOException
	* If there is a problem synchronizing the meta-data.
	*/
	public void synchronizeMetadata() throws IOException {
	synchronized (m_lock) {
	File dir = m_dir;

	if (m_dirChecksum == null \|\| !m_dirChecksum.equals(getDirChecksum(dir))) {
	m_metadata.generateMetadata(dir);
	m_dirChecksum = getDirChecksum(dir);
	}
	}
	}

	public InputStream get(String fileName) throws IOException {
	if (REPOSITORY_XML.equals(fileName)) {
	synchronizeMetadata();
	}

	FileInputStream result = null;
	try {
	result = new FileInputStream(createFile(fileName));
	}
	catch (FileNotFoundException e) {
	// Resource does not exist; notify caller by returning null...
	}

	return result;
	}

	public String put(InputStream data, String fileName, boolean replace) throws IOException {
	if (fileName == null) {
	fileName = "";
	}
	File tempFile = downloadToTempFile(data);

	ResourceMetaData metaData = ResourceMetaData.getBundleMetaData(tempFile);
	if (metaData == null) {
	metaData = ResourceMetaData.getArtifactMetaData(fileName);
	}
	if (metaData == null) {
	tempFile.delete();
	throw new IOException("Not a valid bundle and no filename found (filename = " + fileName + ")");
	}

	File storeLocation = getResourceFile(metaData);
	if (storeLocation == null) {
	tempFile.delete();
	throw new IOException("Failed to store resource (filename = " + fileName + ")");
	}

	if (storeLocation.exists()) {
	if (replace \|\| compare(storeLocation, tempFile)) {
	m_log.log(LogService.LOG_DEBUG, "Exact same resource already existed in OBR (filename = " + fileName + ")");
	}
	else {
	m_log.log(LogService.LOG_ERROR, "Different resource with same name already existed in OBR (filename = " + fileName + ")");
	return null;
	}
	}

	moveFile(tempFile, storeLocation);

	String filePath = storeLocation.toURI().toString().substring(getWorkingDir().toURI().toString().length());
	if (filePath.startsWith("/")) {
	filePath = filePath.substring(1);
	}
	return filePath;
	}

	/** Compares the contents of two files, returns <code>true</code> if they're exactly the same. */
	private boolean compare(File first, File second) throws IOException {
	BufferedInputStream bis = new BufferedInputStream(new FileInputStream(first));
	BufferedInputStream bis2 = new BufferedInputStream(new FileInputStream(second));
	int b1, b2;
	try {
	do {
	b1 = bis.read();
	b2 = bis2.read();
	if (b1 != b2) {
	return false;
	}
	}
	while (b1 != -1 && b2 != -1);
	return (b1 == b2);
	}
	finally {
	if (bis != null) {
	try {
	bis.close();
	}
	catch (IOException e) {
	}
	}
	if (bis2 != null) {
	try {
	bis2.close();
	}
	catch (IOException e) {
	}
	}
	}
	}

	public boolean remove(String fileName) throws IOException {
	File dir;
	synchronized (m_lock) {
	dir = m_dir;
	}

	File file = createFile(fileName);
	if (file.exists()) {
	if (file.delete()) {
	// deleting empty parent dirs
	while ((file = file.getParentFile()) != null && !file.equals(dir) && file.list().length == 0) {
	file.delete();
	}
	return true;
	}
	else {
	throw new IOException("Unable to delete file (" + file.getAbsolutePath() + ")");
	}
	}
	return false;
	}

	public void updated(Dictionary<String, ?> dict) throws ConfigurationException {
	if (dict != null) {
	String path = (String) dict.get(OBRFileStoreConstants.FILE_LOCATION_KEY);
	if (path == null) {
	throw new ConfigurationException(OBRFileStoreConstants.FILE_LOCATION_KEY, "Missing property");
	}

	File newDir = new File(path);
	File curDir = getWorkingDir();

	if (!newDir.equals(curDir)) {
	if (!newDir.exists()) {
	newDir.mkdirs();
	}
	else if (!newDir.isDirectory()) {
	throw new ConfigurationException(OBRFileStoreConstants.FILE_LOCATION_KEY, "Is not a directory: " + newDir);
	}

	synchronized (m_lock) {
	m_dir = newDir;
	m_dirChecksum = "";
	}
	}
	}
	}

	/**
	* Called by dependencymanager upon start of this component.
	*/
	protected void start() {
	try {
	synchronizeMetadata();
	}
	catch (IOException e) {
	m_log.log(LogService.LOG_ERROR, "Could not generate initial meta data for bundle repository");
	}
	}

	/**
	* Computes a magic checksum used to determine whether there where changes in the directory without actually looking
	* into the files or using observation.
	*
	* @param dir
	* The directory
	* @return The checksum
	*/
	private String getDirChecksum(File dir) {
	MessageDigest digest = null;
	try {
	digest = MessageDigest.getInstance("MD5");
	}
	catch (NoSuchAlgorithmException e) {
	// really should not happen
	m_log.log(LogService.LOG_WARNING, "Unable to get an MD5 digest. Metadata will refresh every ten minutes.", e);
	return "" + (System.currentTimeMillis() / 600000);
	}

	Stack<File> dirs = new Stack<>();
	dirs.push(dir);
	while (!dirs.isEmpty()) {
	File pwd = dirs.pop();
	for (File file : pwd.listFiles()) {
	if (file.isDirectory()) {
	dirs.push(file);
	continue;
	}
	// basically we hash the filenames, but...
	// include last-modified to detect touched files
	// include length to work around last-modified rounding issues
	String magic = file.getName() + file.length() + file.lastModified();
	digest.update(magic.getBytes());
	}
	}
	String checksum = new BigInteger(digest.digest()).toString();
	return checksum;
	}

	/**
	* Downloads a given input stream to a temporary file.
	*
	* @param source
	* the input stream to download;
	* @throws IOException
	* in case of I/O problems.
	*/
	private File downloadToTempFile(InputStream source) throws IOException {
	File tempFile = File.createTempFile("obr", ".tmp");
	FileOutputStream fos = null;
	try {
	fos = new FileOutputStream(tempFile);
	int read;
	byte[] buffer = new byte[BUFFER_SIZE];
	while ((read = source.read(buffer)) >= 0) {
	fos.write(buffer, 0, read);
	}
	fos.flush();
	fos.close();
	return tempFile;
	}
	finally {
	closeQuietly(fos);
	}
	}

	/**
	* Encapsulated the store layout strategy by creating the resource file based on the provided meta-data.
	*
	* @param metaData
	* the meta-data for the resource
	* @return the resource file
	* @throws IOException
	* in case of I/O problems.
	*/
	private File getResourceFile(ResourceMetaData metaData) throws IOException {
	File resourceDirectory = getWorkingDir();
	String[] dirs = split(metaData.getSymbolicName());
	for (int i = 0; i < (dirs.length - 1); i++) {
	String subDir = dirs[i];
	resourceDirectory = new File(resourceDirectory, subDir);
	}
	if (!resourceDirectory.exists() && !resourceDirectory.mkdirs()) {
	throw new IOException("Failed to create store directory");
	}

	String name = metaData.getSymbolicName();
	String version = metaData.getVersion();
	if (version != null && !version.equals("") && !version.equals("0.0.0")) {
	name += "-" + version;
	}
	String extension = metaData.getExtension();
	if (extension != null && !extension.equals("")) {
	name += "." + extension;
	}
	return new File(resourceDirectory, name);
	}

	/**
	* Splits a name into parts, breaking at all dots as long as what's behind the dot resembles a Java package name
	* (ie. it starts with a lowercase character).
	*
	* @param name
	* the name to split
	* @return an array of parts
	*/
	public static String[] split(String name) {
	List<String> result = new ArrayList<>();
	int startPos = 0;
	for (int i = 0; i < (name.length() - 1); i++) {
	if (name.charAt(i) == '.') {
	if (Character.isLowerCase(name.charAt(i + 1))) {
	result.add(name.substring(startPos, i));
	i++;
	startPos = i;
	}
	else {
	break;
	}
	}
	}
	result.add(name.substring(startPos));
	return result.toArray(new String[result.size()]);
	}

	/**
	* @return the working directory of this file store.
	*/
	private File getWorkingDir() {
	synchronized (m_lock) {
	return m_dir;
	}
	}

	/**
	* Moves a given source file to a destination location, effectively resulting in a rename.
	*
	* @param source
	* the source file to move;
	* @param dest
	* the destination file to move the file to.
	* @return <code>true</code> if the move succeeded.
	* @throws IOException
	* in case of I/O problems.
	*/
	private boolean moveFile(File source, File dest) throws IOException {
	final int bufferSize = 1024 * 1024; // 1MB

	FileInputStream fis = null;
	FileOutputStream fos = null;
	FileChannel input = null;
	FileChannel output = null;

	try {
	fis = new FileInputStream(source);
	input = fis.getChannel();

	fos = new FileOutputStream(dest);
	output = fos.getChannel();

	long size = input.size();
	long pos = 0;
	while (pos < size) {
	pos += output.transferFrom(input, pos, Math.min(size - pos, bufferSize));
	}
	}
	finally {
	closeQuietly(fos);
	closeQuietly(fis);
	closeQuietly(output);
	closeQuietly(input);
	}

	if (source.length() != dest.length()) {
	throw new IOException("Failed to move file! Not all contents from '" + source + "' copied to '" + dest + "'!");
	}

	dest.setLastModified(source.lastModified());

	if (!source.delete()) {
	dest.delete();
	throw new IOException("Failed to move file! Source file (" + source + ") locked?");
	}

	return true;
	}

	/**
	* Safely closes a given resource, ignoring any I/O exceptions that might occur by this.
	*
	* @param resource
	* the resource to close, can be <code>null</code>.
	*/
	private void closeQuietly(Closeable resource) {
	try {
	if (resource != null) {
	resource.close();
	}
	}
	catch (IOException e) {
	// Ignored...
	}
	}

	/**
	* Creates a {@link File} object with the given file name in the current working directory.
	*
	* @param fileName
	* the name of the file.
	* @return a {@link File} object, never <code>null</code>.
	* @see #getWorkingDir()
	*/
	private File createFile(String fileName) {
	return new File(getWorkingDir(), fileName);
	}
	}