We Keep Coding

Is there a standard way to transform a String into a File considerning the possibility of a URL/URI formatted input String

I would like to obtain the most accurate File typed representation of a String that is supposed to refer to a local (existing) file in one of several forms like:
String file0 = "/home/my_user/file.txt"
String file1 = "file:///home/my_user/file.txt"
String file2 = "file.txt"; // assuming that the working dir is /home/my_user.
Is there a (quasy) single liner using the standard library or perhaps a common third party like apache-commons that would do the trick?
Thanks.

You can define your own function for this purpose. Given below is the function definition and test code:
import java.io.File;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
public class Main {
public static void main(String[] args) {
String file0 = "/Users/arvind.avinash/file.txt";
String file1 = "file:///Users/arvind.avinash/file.txt";
String file2 = "file.txt"; // assuming that the working dir is /Users/arvind.avinash.
System.out.println(getFile(file0).exists());
System.out.println(getFile(file1).exists());
System.out.println(getFile(file2).exists());
}
static File getFile(String pathOrUri) {
URI uri;
File file = null;
try {
uri = new URL(pathOrUri).toURI();
} catch (MalformedURLException e) {
return new File(pathOrUri);
} catch (URISyntaxException e) {
return new File(pathOrUri);
}
if (uri != null) {
file = new File(uri);
}
return file;
}
}
Output:
true
true
true
[Update]
Given below is a more simplified version:
import java.io.File;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
public class Main {
public static void main(String[] args) {
String file0 = "/Users/arvind.avinash/file.txt";
String file1 = "file:///Users/arvind.avinash/file.txt";
String file2 = "file.txt"; // assuming that the working dir is /Users/arvind.avinash.
System.out.println(getFile(file0).exists());
System.out.println(getFile(file1).exists());
System.out.println(getFile(file2).exists());
}
static File getFile(String pathOrUri) {
URI uri;
try {
uri = new URL(pathOrUri).toURI();
} catch (MalformedURLException | URISyntaxException e) {
return new File(pathOrUri);
}
return new File(uri);
}
}

You be able to call new File(x) on examples 1 and 3 and it should work.
As for #2, you can create a URI, and then create File from that. In fact I think they all probably will work using URI
String fileStr = "file:///home/my_user/file.txt";
try {
URI uri = new URI(fileStr);
File f = new File(uri);
} catch (URISyntaxException ex) { ...}

How can I set an auto numeric name generator for image uploads, using a singleton pattern counter

So my Problem is that I have to create a Singleton pattern counter for numeric name giving. For example "1", "2", "3" etc. The idea is that every time i start the application and the Server(tomcat), it gets the last number and when I upload another image it should continue from there. Lets say the last one was "43", so the the next time I start the application it should know it and put "44" for the next image upload.
I'm not that good in Java so please give me some patience :)
This is my FileUploadServlet. It handles the request from the fileUploadForm.jsp by taking the file from the submit.
package upload;
import java.io.IOException;
import java.io.InputStream;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;
import utils.FormatChecker;
import utils.UnzipFile;
//Servlet for handling the Upload request from the Index.jsp
#MultipartConfig
public class FileUploadServlet extends HttpServlet {
// Instace of the FileUpload object
private FileUploader uploader = new FileUploader();
// Instance of the FormatChecker object
private FormatChecker checker = new FormatChecker();
// Instance of the UnzipFile object
private UnzipFile unzip = new UnzipFile();
private static final long serialVersionUID = 1L;
private static final String SAVE_FOLDER = "C:\\Users\\cuche\\Desktop\\tomcat\\apache-tomcat-7.0.47\\webapps\\files";
/**
* #see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.sendRedirect("error.jsp");
}
/**
* #see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
String contentType;
boolean isFormatValid;
Part filePart = request.getPart("file");
contentType = filePart.getContentType();
ServletContext context = getServletContext();
String appPath = context.getRealPath("/");
String fileNameOld = getFileName(filePart);
String fileNameNew = appPath + fileNameOld;
isFormatValid = checker.check(contentType);
pleas ignore the part with the FileUnziper
if (isFormatValid == true) {
if (contentType == ("application/x-zip-compressed")) {
unzip.FileUnziper(fileNameNew, SAVE_FOLDER);
} else {
//gets the content and saves in form of a stream
InputStream fileContent = filePart.getInputStream();
//using the uploadImage method of uploader class
uploader.uploadImage(fileNameNew, fileContent);
}
try {
response.sendRedirect("result.jsp");
} catch (IOException ex) {
response.getWriter().append(ex.getLocalizedMessage());
}
} else {
response.getWriter().append("Format is wrong");
}
}
// method for removing header for proper file upload
private String getFileName(Part part) {
for (String cd : part.getHeader("content-disposition").split(";")) {
if (cd.trim().startsWith("filename")) {
String filename = cd.substring(cd.indexOf('=') + 1).trim()
.replace("\"", "");
return filename.substring(filename.lastIndexOf('/') + 1)
.substring(filename.lastIndexOf('\\') + 1); // MSIE fix.
}
}
return null;
}
}
This is my FileUploader class
package upload;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* #author Iwan Cuche
* #date:
*/
public class FileUploader {
/**
* This method reads a File
*
* #param fileName
* #param stream
*/
public void uploadImage(String fileName, InputStream stream)
throws IOException {
try {
File file = new File(fileName);
OutputStream os = new FileOutputStream(file);
int data;
while ((data = stream.read()) != -1) {
os.write(data);
}
os.flush();
os.close();
System.out.println("Uploaded file successfully saved in "
+ file.getAbsolutePath());
} catch (IOException e) {
e.printStackTrace();
throw e;
}
}
}
This is my Singleton class
package utils;
public class ServerCounter {
private static ServerCounter INSTANCE = new ServerCounter();
private ServerCounter() {};
public static ServerCounter getInstance() {
return INSTANCE;
}
}
I hope someone can help me because I'm not sure how to go at it.

In ServerCounter, add
private final AtomicLong counter = new AtomicLong();
public String nextval() { return String.valueOf(counter.incrementAndGet()); }
Each time you call INSTANCE.nextval() you'll get a fresh numeric string.
Clearly, each time you restart your application, the counter will restart.

ok, first you have to persist your counter if you want to get it after tomcat shutdown. we need listener for tomcat:
package utils;
public class ContextListener implements ServletContextListener{
void contextInitialized(ServletContextEvent sce){ // we could call loadFromFile here as well
}
//will be executed at tomcat shutdown
void contextDestroyed(ServletContextEvent sce){
ServerCounter .getInstance().writeToFile();
}
}
now the singleton(like in Marko's answer:)):
package utils;
public class ServerCounter {
private static ServerCounter INSTANCE = new ServerCounter();
private final AtomicLong counter;
private ServerCounter() {
//load value from file, do you need help by it?
long value = this.loadCounterFromFile();
counter = new AtomicLong(value);
};
private long loadCounterFromFile(){
BufferedReader br = null;
try {
//no problem if there is no file, we will return 0 in this case
br = new BufferedReader(new FileReader("C:\\Test\\counter.txt"));
String line = br.readLine();
if(line != null && line.length() > 0)
return Long.parseLong(line);
return 0;
//catch all exceptionse, because we could get NumberFormatException or FileNotFound from parseLong
} catch (Exception e) {
return 0;
} finally {
try {
if (br != null)br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
public static ServerCounter getInstance() {
return INSTANCE;
}
public String nextval() { return String.valueOf(counter.incrementAndGet()); }
//will be executed by listener
public void writeToFile(){
//write the counter to file
writeToFile(counter.get());
}
private void writeToFile(long value){
try{
//you need folder c:\Test, file will be created automatically if there is no file, it will override the old file
BufferedWriter bw = new BufferedWriter(new FileWriter("C:\\Test\\counter.txt"));
//need "" to create String
bw.write("" + value);
bw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
now you can use ServerCounter.getInstance.nextval() to increment the counter and get the value
last thing is, you need to put the listener to your webApplication:
<web-app>
...
<listener>
<listener-class>utils.ContextListener </listener-class>
</listener>
</web-app>
EDIT: ServerCounter was implementing ServletContextListener by mistake
EDIT2: added read/write file

Read from file inside Eclipse Project

I want to make an application that splits a big text file inside inputfolder into several small XML files to be put inside outputfolder.
This is project outline:
The following code works fine when it comes to getting a file from an outside folder, but when I modified it to read from a folder inside the project, it gave me this error:
Exception in thread "main" java.lang.NullPointerException
at com.zakaria.cut.XmlCutter.cut(XmlCutter.java:45)
at com.zakaria.cut.Main.main(Main.java:8)
[XmlCutter.java]
package com.zakaria.cut;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.text.MessageFormat;
import java.util.logging.ConsoleHandler;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.Logger;
public class XmlCutter {
private static final String OUTPUT_FILE_NAME = "/file";
//private static String USER_HOME = System.getProperty("user.home");
private static final String INPUT_FOLDER = "../inputfolder";
private static String OUTPUT_FOLDER = "../outputfolder";
private static Logger LOG = Logger.getLogger("XmlCutter");
private static long COUNTER = 0;
public XmlCutter() {
super();
// TODO Auto-generated constructor stub
}
public void cut() {
Handler h = new ConsoleHandler();
h.setLevel(Level.FINE);
LOG.addHandler(h);
LOG.setLevel(Level.FINE);
File inputDir = new File(INPUT_FOLDER);
File[] filesInInputDir = inputDir.listFiles();
for (File f : filesInInputDir) {
if ((f.getName()).endsWith(".txt")) {
LOG.fine((MessageFormat.format(
"Found a text file {0}. Processing docs...",
f.getName())));
processFile(f);
}
}
}
private static void processFile(File f) {
StringBuilder out = new StringBuilder();
char prev = '#';
try {
BufferedReader br = new BufferedReader(new InputStreamReader(
new FileInputStream(f), "UTF8"));
char[] buf = new char[1];
while (br.read(buf) >= 0) {
out.append(buf[0]);
if (prev == '<' && buf[0] == '?') {
LOG.finest((MessageFormat.format(
"Start of XML PI Found: {0}{1}", prev, buf[0])));
if (out.length() > 2) {
flushToFile(out.substring(0, out.length() - 2));
}
out.setLength(2);
}
prev = buf[0];
}
LOG.finest("Writing final file");
flushToFile(out.toString());
br.close();
} catch (IOException e) {
LOG.fine(e.getMessage());
}
LOG.fine(MessageFormat.format("Generated {0} XML Documents", COUNTER));
}
private static void flushToFile(String s) {
File f = new File(OUTPUT_FOLDER + OUTPUT_FILE_NAME + (++COUNTER)
+ ".xml");
LOG.finest(MessageFormat.format("Writing file: {0}", f.getName()));
try {
FileOutputStream fos = new FileOutputStream(f);
OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF8");
osw.write(s);
osw.flush();
} catch (IOException e) {
LOG.fine(e.getMessage());
}
}
}
[Main.java]
package com.zakaria.cut;
public class Main {
public static void main(String[] args) {
XmlCutter cutter = new XmlCutter();
cutter.cut();
}
}
The problem, I guess, is definitely here:
private static final String INPUT_FOLDER = "../inputfolder";
private static String OUTPUT_FOLDER = "../outputfolder";
How can I fix it?

Do you know what folder the program is executing from? My guess is the relative links are pointing to the wrong spot? Have you tried hard coding the paths and see if they work? If they do you might have to look at the your execution folder and then change the relative paths accordingly?

File always seems to be empty

Ok, I'm really confused by some code I wrote. It's a DataSetter (didn't know a better name for it...), and has methods to change the data in my data file (data.txt). This data has the following format: #key=value (eg. #version=1.0). Now, I tried to run this line of code:
new DataSetter().setValue("version", "1.1");
It just clears the file. That's pretty much all it does. Now, I think it clears the file because it makes a new File, which is completely empty but has the same name. Here's my code:
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Scanner;
/**
* This class contains methods to set specific data in the data.txt file. <br>
* The data is rewritten every time a new value is set.
*
* #author Casper van Battum
*
*/
public class DataSetter {
private static final File DATA_FILE = new File("resources/data.txt");
private static final String lineFormat = "#%s=%s";
private FileOutputStream out;
private DataReader reader = new DataReader();
private HashMap<String, String> dataMap = reader.getDataMap();
private Scanner scanner;
public DataSetter() {
try {
out = new FileOutputStream(DATA_FILE, false);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
public void setValue(String key, String newValue) {
openDataFile();
String oldLine = String.format(lineFormat, key, dataMap.get(key));
dataMap.put(key, newValue);
String newLine = String.format(lineFormat, key, newValue);
try {
replace(oldLine, newLine);
} catch (IOException e) {
e.printStackTrace();
}
closeDataFile();
}
private void replace(String oldLine, String newLine) throws IOException {
ArrayList<String> tmpData = new ArrayList<String>();
while (scanner.hasNextLine()) {
String currentLine = scanner.nextLine();
tmpData.add((currentLine == oldLine) ? newLine : currentLine);
}
out.write(new String().getBytes());
String sep = System.getProperty("line.separator");
StringBuffer sb = new StringBuffer();
for (String string : tmpData) {
sb.append(string + sep);
}
FileWriter writer = new FileWriter(DATA_FILE);
String outString = sb.toString();
writer.write(outString);
writer.close();
}
private void openDataFile() {
try {
scanner = new Scanner(DATA_FILE);
} catch (FileNotFoundException ex) {
ex.printStackTrace();
}
}
private void closeDataFile() {
scanner.close();
}
}
So after running the setValue() method, I just have an empty file...
Im really out of idea's on how to solve this...

You are truncating your data file with the
new FileOutputStream(DATA_FILE, false)
so no nothing is written when you go to output your the elements in the tmpData ArrayList read from Scanner.
ArrayList<String> tmpData = new ArrayList<String>();
while (scanner.hasNextLine()) {
String currentLine = scanner.nextLine(); // never gets called
...
}
The typical strategy for updating a text file is to create a temporary file with old file's contents (File#renameTo), write the data to file, then delete the temporary file after closing any open streams to the file being read.

Dynamically compiling and Running a Hadoop job from another Java File

I am trying to write a Java file that receives the source code of a MapReduce job, compiles it dynamically and runs the job on a Hadoop cluster. To reach this, I have written 3 methods called compile(), makeJAR() and run_Hadoop_Job(). Everything works fine with the compilation and creation of the JAR file. However, when the job is submitted to Hadoop, as soon as the job starts, it faces problem with finding required Mapper/Reducer classes and throws a ClassNotFoundException for both the Mapper_Class and Reducer_Class *(java.lang.ClassNotFoundException: reza.rCloud.Mapper_Reducer_Classes$Mapper_Class.class)* . I know that there should be something wrong with how I have referenced the required Mapper/Reducer classes but I was not able to figure it out after several. Any help/suggestion on how to solve the issue is highly appreciated.
Regarding the details of the project: I have a file called "rCloud_test/src/reza/Mapper_Reducer_Classes.java" that contains the source code for Mapper_Class and Reducer_Class. This file is ultimately received during the runtime but for now I copied the Hadoop WordCount example in it and store it locally in the same folder as my main class file: rCloud_test/src/reza/Platform2.java.
Here below you can see the main() method of the Platform2.java which is my main class for this project:
public static void main(String[] args){
System.out.println("Code Execution Started");
String className = "Mapper_Reducer_Classes";
Platform2 myPlatform = new Platform2();
//step 1: compile the received class file dynamically:
boolean compResult = myPlatform.compile(className);
System.out.println(className + ".java compilation result: "+compResult);
//step 2: make a JAR file out of the compiled file:
if (compResult) {
compResult = myPlatform.makeJAR("jar_file", myPlatform.compilation_Output_Folder);
System.out.println("JAR creation result: "+compResult);
}
//step 3: Now let's run the Hadoop job:
if (compResult) {
compResult = myPlatform.run_Hadoop_Job(className);
System.out.println("Running on Hadoop result: "+compResult);
}
The method that is causing me all the problems is the run_Hadoop_Job() which is as below:
private boolean run_Hadoop_Job(String className){
try{
System.out.println("*Starting to run the code on Hadoop...");
String[] argsTemp = { "project_test/input", "project_test/output" };
Configuration conf = new Configuration();
conf.set("fs.default.name", "hdfs://localhost:54310");
conf.set("mapred.job.tracker", "localhost:54311");
conf.set("mapred.jar", jar_Output_Folder + "/jar_file"+".jar");
conf.set("libjars", required_Execution_Classes);
//THIS IS WHERE IT CAN'T FIND THE MENTIONED CLASSES, ALTHOUGH THEY EXIST BOTH ON DISK
// AND IN THE CREATED JAR FILE:??????
System.out.println("Getting Mapper/Reducer package name: " +
Mapper_Reducer_Classes.class.getName());
conf.set("mapreduce.map.class", "reza.rCloud.Mapper_Reducer_Classes$Mapper_Class");
conf.set("mapreduce.reduce.class", "reza.rCloud.Mapper_Reducer_Classes$Reducer_Class");
Job job = new Job(conf, "Hadoop Example for dynamically and programmatically compiling-running a job");
job.setJarByClass(Platform2.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path(argsTemp[0]));
FileSystem fs = FileSystem.get(conf);
Path out = new Path(argsTemp[1]);
fs.delete(out, true);
FileOutputFormat.setOutputPath(job, new Path(argsTemp[1]));
//job.submit();
System.out.println("*and now submitting the job to Hadoop...");
System.exit(job.waitForCompletion(true) ? 0 : 1);
System.out.println("Job Finished!");
} catch (Exception e) {
System.out.println("****************Exception!" );
e.printStackTrace();
return false;
}
return true;
}
if needed, here's the source code for the compile() method:
private boolean compile(String className) {
String fileToCompile = JOB_FOLDER + "/" +className+".java";
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
FileOutputStream errorStream = null;
try{
errorStream = new FileOutputStream(JOB_FOLDER + "/logs/Errors.txt");
} catch(FileNotFoundException e){
//if problem creating the file, default wil be console
}
int compilationResult =
compiler.run( null, null, errorStream,
"-classpath", required_Compilation_Classes,
"-d", compilation_Output_Folder,
fileToCompile);
if (compilationResult == 0) {
//Compilation is successful:
return true;
} else {
//Compilation Failed:
return false;
}
}
and the source code for makeJAR() method:
private boolean makeJAR(String outputFileName, String inputDirectory) {
Manifest manifest = new Manifest();
manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION,
"1.0");
JarOutputStream target = null;
try {
target = new JarOutputStream(new FileOutputStream(
jar_Output_Folder+ "/"
+ outputFileName+".jar" ), manifest);
add(new File(inputDirectory), target);
} catch (Exception e) { return false; }
finally {
if (target != null)
try{
target.close();
} catch (Exception e) { return false; }
}
return true;
}
private void add(File source, JarOutputStream target) throws IOException
{
BufferedInputStream in = null;
try
{
if (source.isDirectory())
{
String name = source.getPath().replace("\\", "/");
if (!name.isEmpty())
{
if (!name.endsWith("/"))
name += "/";
JarEntry entry = new JarEntry(name);
entry.setTime(source.lastModified());
target.putNextEntry(entry);
target.closeEntry();
}
for (File nestedFile: source.listFiles())
add(nestedFile, target);
return;
}
JarEntry entry = new JarEntry(source.getPath().replace("\\", "/"));
entry.setTime(source.lastModified());
target.putNextEntry(entry);
in = new BufferedInputStream(new FileInputStream(source));
byte[] buffer = new byte[1024];
while (true)
{
int count = in.read(buffer);
if (count == -1)
break;
target.write(buffer, 0, count);
}
target.closeEntry();
}
finally
{
if (in != null)
in.close();
}
}
and finally the fixed parameters used for accessing the files:
private String JOB_FOLDER = "/Users/reza/My_Software/rCloud_test/src/reza/rCloud";
private String HADOOP_SOURCE_FOLDER = "/Users/reza/My_Software/hadoop-0.20.2";
private String required_Compilation_Classes = HADOOP_SOURCE_FOLDER + "/hadoop-0.20.2-core.jar";
private String required_Execution_Classes = required_Compilation_Classes + "," +
"/Users/reza/My_Software/ActorFoundry_dist_ver/lib/commons-cli-1.1.jar," +
"/Users/reza/My_Software/ActorFoundry_dist_ver/lib/commons-logging-1.1.1.jar";
public String compilation_Output_Folder = "/Users/reza/My_Software/rCloud_test/dyn_classes";
private String jar_Output_Folder = "/Users/reza/My_Software/rCloud_test/dyn_jar";
As a result of running the Platform2, the structure of the project on disk looks as below:
rCloud_test/classes/reza/rCloud/Platform2.class: contain the Platform2 class
rCloud_test/dyn_classes/reza/rCloud/ contains the classes for Mapper_Reducer_Classes.class, Mapper_Reducer_Classes$Mapper_Class.class, and Mapper_Reducer_Classes$Reducer_Class.class
rCloud_test/dyn_jar/jar_file.jar contains the created jar file
REVSED: here's the source code for the rCloud_test/src/reza/rCloud/Mapper_Reducer_Classes.java:
package reza.rCloud;
import java.io.IOException;
import java.lang.InterruptedException;
import java.util.StringTokenizer;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
public class Mapper_Reducer_Classes {
/**
* The map class of WordCount.
*/
public static class Mapper_Class
extends Mapper<Object, Text, Text, IntWritable> {
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, Text value, Context context)
throws IOException, InterruptedException {
StringTokenizer itr = new StringTokenizer(value.toString());
while (itr.hasMoreTokens()) {
word.set(itr.nextToken());
context.write(word, one);
}
}
}
/**
* The reducer class of WordCount
*/
public static class Reducer_Class
extends Reducer<Text, IntWritable, Text, IntWritable> {
public void reduce(Text key, Iterable<IntWritable> values, Context context)
throws IOException, InterruptedException {
int sum = 0;
for (IntWritable value : values) {
sum += value.get();
}
context.write(key, new IntWritable(sum));
}
}
}

Try to set them by using the setClass() method :
conf.setClass("mapreduce.map.class",
Class.forName("reza.rCloud.Mapper_Reducer_Classes$Mapper_Class"),
Mapper.class);
conf.setClass("mapreduce.reduce.class",
Class.forName("reza.rCloud.Mapper_Reducer_Classes$Reducer_Class"),
Reducer.class);