I have to search a string in a file and write the matched lines to another file.
I have a thread to read a file and a thread to write a file. I want to send the stringBuffer from read thread to write thread. Please help me to pass this. I amm getting null value passed.
write thread:
class OutputThread extends Thread{
/****************** Writes the line with search string to the output file *************/
Thread runner1,runner;
File Out_File;
public OutputThread() {
}
public OutputThread(Thread runner,File Out_File) {
runner1 = new Thread(this,"writeThread"); // (1) Create a new thread.
this.Out_File=Out_File;
this.runner=runner;
runner1.start(); // (2) Start the thread.
}
public void run()
{
try{
BufferedWriter bufferedWriter=new BufferedWriter(new FileWriter(Out_File,true));
System.out.println("inside write");
synchronized(runner){
System.out.println("inside wait");
runner.wait();
}
System.out.println("outside wait");
// bufferedWriter.write(line.toString());
Buffer Buf = new Buffer();
bufferedWriter.write(Buf.buffers);
System.out.println(Buf.buffers);
bufferedWriter.flush();
}
catch(Exception e){
System.out.println(e);
e.printStackTrace();
}
}
}
Read Thraed:
class FileThread extends Thread{
Thread runner;
File dir;
String search_string,stats;
File Out_File,final_output;
StringBuffer sb = new StringBuffer();
public FileThread() {
}
public FileThread(CountDownLatch latch,String threadName,File dir,String search_string,File Out_File,File final_output,String stats) {
runner = new Thread(this, threadName); // (1) Create a new thread.
this.dir=dir;
this.search_string=search_string;
this.Out_File=Out_File;
this.stats=stats;
this.final_output=final_output;
this.latch=latch;
runner.start(); // (2) Start the thread.
}
public void run()
{
try{
Enumeration entries;
ZipFile zipFile;
String source_file_name = dir.toString();
File Source_file = dir;
String extension;
OutputThread out = new OutputThread(runner,Out_File);
int dotPos = source_file_name.lastIndexOf(".");
extension = source_file_name.substring(dotPos+1);
if(extension.equals("zip"))
{
zipFile = new ZipFile(source_file_name);
entries = zipFile.entries();
while(entries.hasMoreElements()) {
ZipEntry entry = (ZipEntry)entries.nextElement();
if(entry.isDirectory()) {
(new File(entry.getName())).mkdir();
continue;
}
searchString(runner,entry.getName(),new BufferedInputStream(zipFile.getInputStream(entry)),Out_File,final_output,search_string,stats);
}
zipFile.close();
}
else
{
searchString(runner,Source_file.toString(),new BufferedInputStream(new FileInputStream(Source_file)),Out_File,final_output,search_string,stats);
}
}
catch(Exception e){
System.out.println(e);
e.printStackTrace();
}
}
/********* Reads the Input Files and Searches for the String ******************************/
public void searchString(Thread runner,String Source_File,BufferedInputStream in,File output_file,File final_output,String search,String stats)
{
int count = 0;
int countw = 0;
int countl=0;
String s;
String[] str;
String newLine = System.getProperty("line.separator");
try
{
BufferedReader br2 = new BufferedReader(new InputStreamReader(in));
//OutputFile outfile = new OutputFile();
BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(output_file,true));
Buffer Buf = new Buffer();
//StringBuffer sb = new StringBuffer();
StringBuffer sb1 = new StringBuffer();
while((s = br2.readLine()) != null )
{
str = s.split(search);
count = str.length-1;
countw += count;
if(s.contains(search)){
countl++;
sb.append(s);
sb.append(newLine);
}
if(countl%100==0)
{ System.out.println("inside count");
Buf.setBuffers(sb.toString());
sb.delete(0,sb.length());
System.out.println("outside notify");
synchronized(runner)
{
runner.notify();
}
//outfile.WriteFile(sb,bufferedWriter);
//sb.delete(0,sb.length());
}
}
}
synchronized(runner)
{
runner.notify();
}
br2.close();
in.close();
if(countw == 0)
{
System.out.println("Input File : "+Source_File );
System.out.println("Word not found");
System.exit(0);
}
else
{
System.out.println("Input File : "+Source_File );
System.out.println("Matched word count : "+countw );
System.out.println("Lines with Search String : "+countl);
System.out.println("Output File : "+output_file.toString());
System.out.println();
}
}
catch(Exception e){
System.out.println(e);
e.printStackTrace();
}
}
}
Here is the approach I would use:
Add a queue to the output thread. Make sure access is synchronized.
Add a method to the output thread (say addWork) that accepts a String and adds it to the output queue.
Let the run method of the output thread continually dequeue Strings and write them to the file.
Let the other thread pass Strings to the output thread by calling addWork(String).
Pass the stringbuffer in as a parameter to both.
Any time you access the stringbuffer, make sure you do it inside a synchronized block
synchronized(myStringBuffer) {
myStringBuffer.append("Awesome text");
}
and
synchronized(myStringBuffer) {
myFileOutput.writeln(myStringBuffer.toString());
}
examples above.
Related
I want to use Java export Oracle database, and obtain the export status(indicates success or failure), if the operation failed, should return the reason why failed.
But I have trouble in this problem, the export is success,but the label I defined is always false and return [].
What should I do to get the true status or obtain the failure details.
public class DumpFile {
/**
* Default constructor
*/
public DumpFile() {
}
/**
* #return
* #throws InterruptedException
*/
public static boolean LoadToOracle(String Path) throws InterruptedException {
String importStr = "imp scott/tiger#orcl file="+Path+" full=y ignore=y";
Process process_oracle = null;
boolean flag = false;
List<String[]> processListOracle = new ArrayList<String[]>();
try {
process_oracle = Runtime.getRuntime().exec(importStr);
process_oracle.waitFor();
BufferedReader input = new BufferedReader(new InputStreamReader(
process_oracle.getInputStream(), "utf8"));
String line = "";
while ((line = input.readLine()) != null) {
System.out.println(line);
String[] content = line.split("\n");
processListOracle.add(content);
}
int exevalue = process_oracle.waitFor();
System.out.println("exevalue:"+exevalue);
input.close();
} catch (Exception e) {
e.printStackTrace();
}
for (String[] line : processListOracle)
for (String temp : line) {
if (temp.trim().equals("successfully"))
flag = true;
}
return flag;
}
public static String exportFromOracle(String FileName) throws InterruptedException {
String Path="/home/oracle/output/";
String exportStr = "exp scott/tiger#orcl file="+Path+FileName;
Process process_oracle = null;
boolean flag = false;
List<String[]> processListOracle = new ArrayList<String[]>();
try {
process_oracle = Runtime.getRuntime().exec(exportStr);
BufferedReader input = new BufferedReader(new InputStreamReader(
process_oracle.getInputStream(), "utf8"));
String line = "";
while ((line = input.readLine()) != null) {
System.out.println("line:"+line);
String[] content = line.split("\n");
processListOracle.add(content);
}
int exevalue = process_oracle.waitFor();
System.out.println("exevalue:"+exevalue);
input.close();
} catch (Exception e) {
e.printStackTrace();
}
for (String[] line : processListOracle)
for (String temp : line) {
if (temp.trim().equals("successfully"))
flag = true;
}
System.out.println("flag:"+flag);
if (flag==true)
return flag+"test"+Path;
else{
for (String[] line : processListOracle)
System.out.println(line);
}
return processListOracle.toString();
}
public static void main(String[] args) throws Exception {
String a=exportFromOracle("test.dmp");
System.out.println("a.isEmpty:"+a.isEmpty());
System.out.println(a);
}
}
OUTPUT:
exevalue:0
a.isEmpty:false
[]
I have solved this problem by "log file", I use imp export the database and output the log file, then I use Java to read the log file, to obtain the status.
I am trying to do external merge sort. Method: opening all the files in the folder 'output' and getting 1st line and sorting it, and writing it in the 'final' file and then getting the 2nd line of that file and repeating. I get an StackOverflowError. Here my file size is greater then memory.
public class mergefile6 {
public static ArrayList<String> al = new ArrayList<String>();
static HashMap hm = new HashMap();
public static String line;
public static String[][] filepoint = new String[100][2];
public static int fileline=1;
public static int i=0;
public static void main(String[] args) throws Exception{
fileread();
}
public static void fileread() throws Exception{
FileReader fileReader = null;
BufferedReader bufferedReader = null;
try {
File folder = new File("./output/");
if (folder.isDirectory()) {
for (File file : folder.listFiles()) {
fileReader = new FileReader(file);
bufferedReader = new BufferedReader(fileReader);
int lineCount = 0;
while ((line = bufferedReader.readLine())!=null) {
lineCount++;
if (1 == lineCount) {
hm.put(line,file);
al.add(line);
filepoint[i][0]=file.toString();
filepoint[i][1]=Integer.toString(fileline);
++i;
}
}
}
}
if (null != fileReader){
try {
fileReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != bufferedReader){
try {
bufferedReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
Sorting(al);
test(al);
} catch (Exception e) {
} finally {
}
}
public static void Sorting(ArrayList<String> al)throws Exception{
int length = al.size();
ArrayList<String> tmp = new ArrayList<String>(al);
mergeSort(al, tmp, 0, al.size() - 1);
}
private static void mergeSort(ArrayList<String> al, ArrayList<String> tmp, int left, int right){
//sort code
}
public static void test(ArrayList<String> al) throws Exception{
BufferedWriter bw = null;
FileWriter fw = null;
fw = new FileWriter("final",true);
bw = new BufferedWriter(fw);
bw.write(al.get(0)+" \n");
//bw.flush();
bw.close();
fw.close();
String filename = hm.get(al.get(0)).toString();
hm.remove(al.get(0));
al.remove(0);
fileforward(filename,al);
}
public static void fileforward(String filename,ArrayList<String> al) throws Exception{
long list;
FileReader fr = null;
BufferedReader br = null;
fr = new FileReader(filename);
br = new BufferedReader(fr);
for(int j=0;j<i;++j){
if(filepoint[j][0] == filename){
fileline = Integer.parseInt(filepoint[j][1]);
list = br.skip(99*fileline);
if((line = br.readLine())!=null){
hm.put(line,filename);
al.add(line);
++fileline;
filepoint[j][1]=Integer.toString(fileline);
br.close(); fr.close();
}else{}
}
}
if(al.size()==3){
Sorting(al);
test(al); }
}
}
What may be causing this error to come?
It might be an overflow caused by the mutual calls between fileforward() and test(). I don't know try debugging the ArrayList's size with logs or prints. If it's always equal to 3 that's the problem.
I'm working on a homework assignment and have run into an odd "ArrayOutOfBoundsException" error - I know what the error means (essentially I'm trying to reference a location in an array that isn't there) but I'm not sure why it's throwing that error? I'm not sure what I'm missing, but obviously there must be some logic error somewhere that I'm not seeing.
PhoneDirectory.java
import java.util.HashMap;
import java.io.*;
class PhoneDirectory {
private HashMap<String, String> directoryMap;
File directory;
public PhoneDirectory() { //create file for phone-directory
directory = new File("phone-directory.txt");
directoryMap = new HashMap<String, String>();
try(BufferedReader buffer = new BufferedReader(new FileReader(directory))) {
String currentLine;
while((currentLine = buffer.readLine()) != null) { //set currentLine = buffer.readLine() and check if not null
String[] fileData = currentLine.split(","); //create array of values in text file - split by comma
directoryMap.put(fileData[0], fileData[1]); //add item to directoryMap
}
}
catch(IOException err) {
err.printStackTrace();
}
}
public PhoneDirectory(String phoneDirectoryFile) {
directory = new File(phoneDirectoryFile);
directoryMap = new HashMap<String, String>();
try(BufferedReader buffer = new BufferedReader(new FileReader(directory))) {
String currentLine;
while((currentLine = buffer.readLine()) != null) { //set currentLine = buffer.readLine() and check if not null
String[] fileData = currentLine.split(","); //create array of values in text file - split by comma
directoryMap.put(fileData[0], fileData[1]); //add item to directoryMap
}
}
catch(IOException err) {
err.printStackTrace();
}
}
public String Lookup(String personName) {
if(directoryMap.containsKey(personName))
return directoryMap.get(personName);
else
return "This person is not in the directory.";
}
public void AddOrChangeEntry(String name, String phoneNumber) {
//ASK IF "IF-ELSE" CHECK IS NECESSARY
if(directoryMap.containsKey(name))
directoryMap.put(name,phoneNumber); //if name is a key, update listing
else
directoryMap.put(name, phoneNumber); //otherwise - create new entry with name
}
public void DeleteEntry(String name) {
if(directoryMap.containsKey(name))
directoryMap.remove(name);
else
System.out.println("The person you are looking for is not in this directory.");
}
public void Write() {
try(BufferedWriter writeDestination = new BufferedWriter(new FileWriter(directory)))
{
for(String key : directoryMap.keySet())
{
writeDestination.write(key + ", " + directoryMap.get(key) + '\n');
writeDestination.newLine();
}
}
catch(IOException err) {
err.printStackTrace();
}
}
}
Driver.java
public class Driver {
PhoneDirectory list1;
public static void main(String[] args) {
PhoneDirectory list1 = new PhoneDirectory("test.txt");
list1.AddOrChangeEntry("Disney World","123-456-7890");
list1.Write();
}
}
Essentially I'm creating a file called "test.txt" and adding the line "Disney World, 123-456-7890" - what's weird is that the code still works - but it throws me that error anyway, so what's really happening? (For the record, I'm referring to the line(s): directoryMap.put(fileData[0], fileData[1]) - which would be line 14 and 28 respectively.)
My goal is to read in a text file and add each element to a simple array (the elements are separated by a comma). The last method readData() is the one I can't figure out.
My code so far :
public class VersionChooser {
private Scanner scan;
private StockManager aManager = new StockManager("StockManager");
public VersionChooser() {
this.scan = new Scanner(System.in);
}
public void chooseVersion() {
this.readData();
this.runTextOption();
}
private void runTextOption() {
StockTUI tui = new StockTUI(this.aManager);
}
public StockManager readData() {
String fileName;
System.out.println("Enter the name of the file to be used");
fileName = this.scan.nextLine();
System.out.println(fileName);
try (final BufferedReader br = Files.newBufferedReader(new File("fileName").toPath(),
StandardCharsets.UTF_16)) {
for (String line; (line = br.readLine()) != null;) {
final String[] data = line.split(",");
StockRecord record = new StockRecord(data[0], Double.valueOf(data[4]));
this.aManager.getStockList().add(record);
}
} catch (IOException ioe) {
ioe.printStackTrace();
}
return null;
}
}
StockRecord :
public class StockRecord {
private String date;
private double closingPrice;
public StockRecord(String date, double closingPrice) {
this.date = date;
this.closingPrice = closingPrice;
}
public String getDate() {
return this.date;
}
public double getClosingPrice() {
return this.closingPrice;
}
public String toString() {
return "On " + this.date + " this stock had a closing price of $"
+ this.closingPrice;
}
}
Step1 : Read the file line by line.
Step2: Split the line by ","
Step3 : Construct the String[] to StockRecord.
try (final BufferedReader br = Files.newBufferedReader(new File("stock.txt").toPath(),
StandardCharsets.UTF_8)) {
List<StockRecord> stocks = new ArrayList<StockRecord>();
br.readLine() ; // to avoid first line
for (String line; (line = br.readLine()) != null;) { // first step
final String[] data = line.split(","); // second step
StockRecord record = new StockRecord(data[0], Double.valueOf(data[1]));
stocks.add(record); // third step
}
} catch (IOException e) {
e.printStackTrace();
}
Your stockRecord doesn't has all records. and for demo purpose i did assumed 2 element is closing price . change accordingly
I have created a sequence file out of directory and then given index according to groups I want so that I can create groups using that index. This groups are then given one by one to my customized java class which gives information based on the file present in the group.
My problem is that some time it runs perfectly but some time gives different errors like null pointer exception, data type of field not found.
The problem is may be due to size of group. Because I am creating folder based group and then do the fetches the information from that folder inside my customized jar.
So how can I resolve this issue?
Below is my java class code:
public class OperateDirectory extends EvalFunc<DataBag>{
public TupleFactory tupleFactory = TupleFactory.getInstance();
public BagFactory bagFactory = BagFactory.getInstance();
public DataBag exec(Tuple input) throws IOException{
ArrayList<String> protoTuple = new ArrayList<>();
DataBag dataBag = bagFactory.newDefaultBag();
/* Create Directory */
if(input == null)
return dataBag;
if(input.size() != 2)
return dataBag;
long id = (long)input.get(0);
DataBag infoBag = (DataBag)input.get(1);
Iterator<Tuple> it = infoBag.iterator();
File dir = new File("/tmp/TestFolder"+id);
if(dir.exists())
{
FileUtils.cleanDirectory(dir);
}
else
{
dir.mkdir();
}
while(it.hasNext())
{
Tuple file_details = (Tuple)it.next();
if(file_details != null && file_details.size()==3)
{
String file_name = (String)file_details.get(1);
BytesWritable file_contents = (BytesWritable)file_details.get(2);
File f = new File(dir.getPath()+"/"+file_name);
f.deleteOnExit();
writeToFile(file_contents, f);
}
}
/* Perform operation here */
File f = new File("output"+id+".log");
ProcessBuilder performProcess1 = new ProcessBuilder("processes/processor", dir.getPath(),f.getPath());
Process process1 = performProcess1.start();
try
{
process1.waitFor();
if(f.exists() && f.length()>0)
{
ProcessBuilder performProcess2 = new ProcessBuilder("perl", "scripts/ParseFile.pl", f.getPath());
Process process2 = performProcess2.start();
InputStream is = process2.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
while ((line = br.readLine()) != null)
{
if(!line.isEmpty())
{
String [] tmpArray = line.split(",");
if(tmpArray.length == 2)
{
protoTuple.clear();
protoTuple.add(tmpArray[0]);
protoTuple.add(tmpArray[1]);
dataBag.add(tupleFactory.newTuple(protoTuple));
}
}
}
}
else
{
protoTuple.clear();
protoTuple.add("Error");
protoTuple.add("File "+f.getPath()+" does not exists ");
dataBag.add(tupleFactory.newTuple(protoTuple));
}
}
catch(Exception e)
{
protoTuple.clear();
protoTuple.add("Error ");
protoTuple.add(e.getMessage());
dataBag.add(tupleFactory.newTuple(protoTuple));
}
try
{
FileUtils.cleanDirectory(dir);
FileUtils.deleteDirectory(dir);
}
catch(Exception e)
{
}
return dataBag;
}
void writeToFile(BytesWritable value, File binaryFile) throws IOException{
FileOutputStream fileOut = new FileOutputStream(binaryFile);
fileOut.write(value.getBytes(), 0, value.getLength());
fileOut.close();
}
}