Develop Reference

Not able to read individual page using PDFTextStripper with multiple threads

I am able to create 10 threads. But the problem is when I try to access individual page using those threads in parallel style. I have tried putting the private static PDFTextStripper instance into synchronized block as well. Still I get below exception:
COSStream has been closed and cannot be read. Perhaps its enclosing PDDocument has been closed?
trying to print first word from each page for first 10 pages, but its not working. This is my first experiment with Multithreading and PDF reading. Any help would be much appreciated.
public class ReadPDFFile extends Thread implements FileInstance {
private static String fileLocation;
private static String fileNameIV;
private static String userInput;
private static int userConfidence;
private static int totalPages;
private static ConcurrentHashMap<Integer, List<String>> map = null;
private Iterator<PDDocument> iteratorForThisDoc;
private PDFTextStripperByArea text;
private static PDFTextStripper pdfStrip = null;
private static PDFParser pdParser = null;
private Splitter splitter;
private static int counter=0;
private StringWriter writer;
private static ReentrantLock counterLock = new ReentrantLock(true);
private static PDDocument doc;
private static PDDocument doc2;
private static boolean flag = false;
List<PDDocument> listOfPages;
ReadPDFFile(String filePath, String fileName, String userSearch, int confidence) throws FileNotFoundException{
fileLocation= filePath;
fileNameIV = fileName;
userInput= userSearch;
userConfidence = confidence;
System.out.println("object created");
}
#Override
public void createFileInstance(String filePath, String fileName) {
List<String> list = new ArrayList<String>();
map = new ConcurrentHashMap<Integer, List<String>>();
try(PDDocument document = PDDocument.load(new File(filePath))){
doc = document;
pdfStrip = new PDFTextStripper();
this.splitter = new Splitter();
text = new PDFTextStripperByArea();
document.getClass();
if(!document.isEncrypted()) {
totalPages = document.getNumberOfPages();
System.out.println("Number of pages in this book "+totalPages);
listOfPages = splitter.split(document);
iteratorForThisDoc = listOfPages.iterator();
}
this.createThreads();
/*
* for(int i=0;i<1759;i++) { readThisPage(i, pdfStrip); } flag= true;
*/
}
catch(IOException ie) {
ie.printStackTrace();
}
}
public void createThreads() {
counter=1;
for(int i=0;i<=9;i++) {
ReadPDFFile pdf = new ReadPDFFile();
pdf.setName("Reader"+i);
pdf.start();
}
}
public void run() {
try {
while(counter < 10){
int pgNum= pageCounterReentrant();
readThisPage(pgNum, pdfStrip);
}
doc.close();
}catch(Exception e) {
}
flag= true;
}
public static int getCounter() {
counter= counter+1;
return counter;
}
public static int pageCounterReentrant() {
counterLock.lock();
try {
counter = getCounter();
} finally {
counterLock.unlock();
}
return counter;
}
public static void readThisPage(int pageNum, PDFTextStripper ts) {
counter++;
System.out.println(Thread.currentThread().getName()+" reading page: "+pageNum+", counter: "+counter);
synchronized(ts){
String currentpageContent= new String();
try {
ts.setStartPage(pageNum);
ts.setEndPage(pageNum);
System.out.println("-->"+ts.getPageEnd());
currentpageContent = ts.getText(doc);
currentpageContent = currentpageContent.substring(0, 10);
System.out.println("\n\n "+currentpageContent);
}
/*
* further operations on currentpageContent here
*/
catch(IOException io) {
io.printStackTrace();
}finally {
}
}
}
public static void printFinalResult(ConcurrentHashMap<Integer, List<String>> map) {
/*
* simply display content of ConcurrentHashMap
*/
}
public static void main(String[] args) throws FileNotFoundException {
Scanner sc = new Scanner(System.in);
System.out.println("Search Word");
userInput = sc.nextLine();
System.out.println("Confidence");
userConfidence = sc.nextInt();
ReadPDFFile pef = new ReadPDFFile("file path", "file name",userInput, userConfidence);
pef.createFileInstance("file path ","file name");
if(flag==true)
printFinalResult(map);
}
}
If I read each page in a for loop sequentially using one thread then it is able to print the content, but not with multithreads. You can see that code commented in void createFileInstance(), after this.createThreads(); I wish to get string content of each pdf page individually, using threads, and then perform operation on it. I have the logic to collect each word token into List but before moving ahead, I need to solve this problem.

Your code looks like this:
try(PDDocument document = PDDocument.load(new File(filePath))){
doc = document;
....
this.createThreads();
} // document gets closed here
...
//threads that do text extraction still running here (and using a closed object)
These threads use doc to extract the text (ts.getText(doc)). However at this time, the PDDocument object is already closed due to the usage of try-with-resources, and its streams also closed. Thus the error message "Perhaps its enclosing PDDocument has been closed?".
You should create the thread before closing the document, and waiting for all threads to finish before closing it.
I'd advise against using multithreading on one PDDocument, see PDFBOX-4559. You could create several PDDocuments and then extract on these, or not do it at all. Text extraction works pretty fast in PDFBox (compared to rendering).

Why isn't this multithreaded code faster?

This is my java code. Before, it calls BatchGenerateResult sequentially which is a lengthy process, but I want to try some multithreading and have each one of them run at the same time. However when I test it, the new time is the same as the old time. I expected the new time to be faster. Does anyone know whats wrong?
public class PlutoMake {
public static String classDir;
public static void main(String[] args) throws JSONException, IOException,
InterruptedException {
// determine path to the class file, I will use it as current directory
String classDirFile = PlutoMake.class.getResource("PlutoMake.class")
.getPath();
classDir = classDirFile.substring(0, classDirFile.lastIndexOf("/") + 1);
// get the input arguments
final String logoPath;
final String filename;
if (args.length < 2) {
logoPath = classDir + "tests/android.png";
filename = "result.png";
} else {
logoPath = args[0];
filename = args[1];
}
// make sure the logo image exists
File logofile = new File(logoPath);
if (!logofile.exists() || logofile.isDirectory()) {
System.exit(1);
}
// get the master.js file
String text = readFile(classDir + "master.js");
JSONArray files = new JSONArray(text);
ExecutorService es = Executors.newCachedThreadPool();
// loop through all active templates
int len = files.length();
for (int i = 0; i < len; i += 1) {
final JSONObject template = files.getJSONObject(i);
if (template.getBoolean("active")) {
es.execute(new Runnable() {
#Override
public void run() {
try {
BatchGenerateResult(logoPath, template.getString("template"),
template.getString("mapping"),
template.getString("metadata"), template.getString("result")
+ filename, template.getString("filter"),
template.getString("mask"), template.getInt("x"),
template.getInt("y"), template.getInt("w"),
template.getInt("h"));
} catch (IOException | JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
}
es.shutdown();
boolean finshed = es.awaitTermination(2, TimeUnit.MINUTES);
}
private static void BatchGenerateResult(String logoPath, String templatePath,
String mappingPath, String metadataPath, String resultPath,
String filter, String maskPath, int x, int y, int w, int h)
throws IOException, JSONException {
ColorFilter filterobj = null;
if (filter.equals("none")) {
filterobj = new NoFilter();
} else if (filter.equals("darken")) {
filterobj = new Darken();
} else if (filter.equals("vividlight")) {
filterobj = new VividLight();
} else {
System.exit(1);
}
String text = readFile(classDir + metadataPath);
JSONObject metadata = new JSONObject(text);
Map<Point, Point> mapping = MyJSON.ReadMapping(classDir + mappingPath);
BufferedImage warpedimage = Exporter.GenerateWarpedLogo(logoPath, maskPath,
mapping, metadata.getInt("width"), metadata.getInt("height"));
// ImageIO.write(warpedimage, "png", new FileOutputStream(classDir +
// "warpedlogo.png"));
Exporter.StampLogo(templatePath, resultPath, x, y, w, h, warpedimage,
filterobj);
warpedimage.flush();
}
private static String readFile(String path) throws IOException {
File file = new File(path);
FileInputStream fis = new FileInputStream(file);
byte[] data = new byte[(int) file.length()];
fis.read(data);
fis.close();
String text = new String(data, "UTF-8");
return text;
}
}

It looks like, for all practical purposes the following code should be the only one which can improve performance by using multithreading.
BufferedImage warpedimage = Exporter.GenerateWarpedLogo(logoPath, maskPath,
mapping, metadata.getInt("width"), metadata.getInt("height"));
// ImageIO.write(warpedimage, "png", new FileOutputStream(classDir +
// "warpedlogo.png"));
Exporter.StampLogo(templatePath, resultPath, x, y, w, h, warpedimage,
filterobj);
The rest of it major IO - I doubt how much performance improvement you can achieve there.
Do a profile and check how long each one of the methods is executing. Depending on that you should be able to understand.

Hi sorry not able add to comment part as just joined..
would suggest to first go for dummy method any check whether it works at your end then add your business logic...
if the sample works then you might need to check your "template" class
here's the sample.. check the timestamp
package example;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class ExecutorStaticExample {
public static void main(String[] args){
ExecutorService ex = Executors.newCachedThreadPool();
for (int i=0;i<10;i++){
ex.execute(new Runnable(){
#Override
public void run() {
helloStatic();
System.out.println(System.currentTimeMillis());
}
});
}
}
static void helloStatic(){
System.out.println("hello form static");
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

PDF PrinterJob get Job status

I have an issue to print a PDF using java. I know that Java doesn't support print PDF natively cause java doesn't have a PDF renderer. So to solve this problem I'm using a PDFRenderer library and here is an example for printing with it:
File f = new File("myfile.pdf");
FileInputStream fis = new FileInputStream(f);
FileChannel fc = fis.getChannel();
ByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0,
fc.size());
PDFFile pdfFile = new PDFFile(bb);
PDFPrintPage pages = new PDFPrintPage(pdfFile);
PrinterJob pjob = PrinterJob.getPrinterJob();
PageFormat pf = PrinterJob.getPrinterJob().defaultPage();
pjob.setJobName(f.getName());
pjob.setPrintService(mPrintService);
Book book = new Book();
book.append(pages, pf, pdfFile.getNumPages());
pjob.setPageable(book);
pjob.print();
It works fine, but I need some way to get status of my printer job. I need to know when my printer job was finished that I can start another. Java API has a good solution with DocPrintJob and PrintJobListener but I need to use PrinterJob for my PDF printing. So how I can listen the job status from my PrinterJob like it does in DocPrintJob?

javafx.print
Enum PrinterJob.JobStatus
java.lang.Object
java.lang.Enum<PrinterJob.JobStatus>
javafx.print.PrinterJob.JobStatus
public static PrinterJob.JobStatus[] values()
Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:
for (PrinterJob.JobStatus c : PrinterJob.JobStatus.values())
System.out.println(c);

For anyone dealing with this problem here in 2020, I found a pretty slick way of printing PDF files while being able to monitor the print job, without using JavaFX - as people don't seem to be too hip on using JavaFX for printing PDF files, and I'm not to keen on object node printing, as it is really diffiult to get the print out to look like a normal document in my opinion ... JavaFX seems to like the idea of - basically - screen shotting a portion of your form, then rendering that snap shot as a graphic, then you have to scale it for the printer and it just ends up looking kinda weird ... whereas taking something like nicely formatted HTML, and printing it through a PDF library is really clean, and really fast. So here is what I found:
First, I used this library, which is free, to render my HTML String into a PDF file. Here is the Maven source for the library:
<dependency>
<groupId>org.icepdf.os</groupId>
<artifactId>icepdf-core</artifactId>
<version>6.2.2</version>
</dependency>
And here is my code for rendering the PDF:
String docPath = "/Users/michael/Documents/JavaFile.pdf";
String html = "<html>Any HTML Code you want, including embedded CSS for a really clean look</html>
OutputStream outputStream = new FileOutputStream(docPath);
ITextRenderer renderer = new ITextRenderer();
renderer.setDocumentFromString(html);
renderer.layout();
renderer.createPDF(outputStream);
outputStream.close();
And here is my class for printing the PDF ... its a little lengthy, but VERY simple, and it uses native Java API which is nice (i'm using 1.8):
import javafx.application.Platform;
import javafx.scene.control.Label;
import java.io.*;
import javax.print.*;
import javax.print.event.PrintJobAdapter;
import javax.print.event.PrintJobEvent;
public class PrintHandler {
private void delay(int msec) {
try {
Thread.sleep(msec);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public PrintHandler (FileInputStream fis, Label statusLabel) {
this.statusLabel = statusLabel;
this.fis = fis;
}
private FileInputStream fis;
private Label statusLabel;
private String state;
public void startPrintJob () {
try {
Platform.runLater(()->statusLabel.setText("PRINTING"));
delay(5000);
InputStream is = new BufferedInputStream(this.fis);
DocFlavor flavor = DocFlavor.INPUT_STREAM.PDF;
PrintService service = PrintServiceLookup.lookupDefaultPrintService();
DocPrintJob printJob = service.createPrintJob();
JobMonitor monitor = new JobMonitor();
printJob.addPrintJobListener(monitor);
Doc doc = new SimpleDoc(is, flavor, null);
printJob.print(doc, null);
monitor.waitForJobCompletion();
is.close();
} catch (PrintException | IOException e) {
e.printStackTrace();
}
}
private class JobMonitor extends PrintJobAdapter {
private boolean notify = false;
final int DATA_TRANSFERRED = 10;
final int JOB_COMPLETE = 11;
final int JOB_FAILED = 12;
final int JOB_CANCELED = 13;
final int JOB_NO_MORE_EVENTS = 14;
final int JOB_NEEDS_ATTENTION = 15;
private int status;
#Override
public void printDataTransferCompleted(PrintJobEvent pje) {
status = DATA_TRANSFERRED;
markAction();
}
#Override
public void printJobCompleted(PrintJobEvent pje) {
status = JOB_COMPLETE;
markAction();
}
#Override
public void printJobFailed(PrintJobEvent pje) {
status = JOB_FAILED;
markAction();
}
#Override
public void printJobCanceled(PrintJobEvent pje) {
status = JOB_CANCELED;
markAction();
}
#Override
public void printJobNoMoreEvents(PrintJobEvent pje) {
status = JOB_NO_MORE_EVENTS;
markAction();
}
#Override
public void printJobRequiresAttention(PrintJobEvent pje) {
status = JOB_NEEDS_ATTENTION;
markAction();
}
private void markAction() {
synchronized (JobMonitor.this) {
notify = true;
JobMonitor.this.notify();
}
}
public synchronized void waitForJobCompletion() {
Runnable runner = ()->{
boolean keepRunning = true;
while (keepRunning) {
try {
while (!notify) {
wait();
}
switch(this.status){
case DATA_TRANSFERRED:
state = "DATA_TRANSFERRED";
break;
case JOB_COMPLETE:
state = "JOB_FINISHED";
keepRunning = false;
break;
case JOB_FAILED:
state = "JOB_FAILED";
keepRunning = false;
break;
case JOB_CANCELED:
state = "JOB_CANCELED";
keepRunning = false;
break;
case JOB_NO_MORE_EVENTS:
state = "JOB_COMPLETE";
keepRunning = false;
break;
case JOB_NEEDS_ATTENTION:
state = "JOB_NEEDS_ATTENTION";
break;
}
Platform.runLater(()->statusLabel.setText(state));
delay(5000);
notify = false;
}
catch (InterruptedException e) {}
}
delay(5000);
Platform.runLater(()->statusLabel.setText(""));
};
Thread monitor = new Thread(runner);
monitor.start();
}
}
}
And here is how I invoke the class to print and monitor the job:
FileInputStream fis = new FileInputStream(docPath);
Label jobStatus = new Label(); //Already in my AnchorPane but included here for clarity
new PrintHandler(fis,jobStatus).startPrintJob();

Get ID lexemes in lexer class ANTLR3 that implemented to a jTable

I am building a java clone code detector in swing that implemented the ANTLR. This is the Screenshot :
https://www.dropbox.com/s/wnumgsjmpps33v5/SemogaYaAllah.png
if you see the screenshot, there are a main file that compared to another files. The way that I do is compared thats token main file to another file. The problem is, I am failed to get the ID Lexemes or tokens from my lexer class.
This is my ANTLR3JavaLexer
public class Antlr3JavaLexer extends Lexer {
public static final int PACKAGE=84;
public static final int EXPONENT=173;
public static final int STAR=49;
public static final int WHILE=103;
public static final int MOD=32;
public static final int MOD_ASSIGN=33;
public static final int CASE=58;
public static final int CHAR=60;
I ve created a JavaParser.class like this to use that lexer:
public final class JavaParser extends AParser { //Parser is my Abstract Class
JavaParser() {
}
#Override
protected boolean parseFile(JCCDFile f, final ASTManager treeContainer)throws ParseException, IOException {
BufferedReader in = new BufferedReader(new FileReader(f.getFile()));
String filePath = f.getNama(); // getName of file
final Antlr3JavaLexer lexer = new Antlr3JavaLexer();
lexer.preserveWhitespacesAndComments = false;
try {
lexer.setCharStream(new ANTLRReaderStream(in));
} catch (IOException e) {
e.printStackTrace();
return false;
}
//This is the problem
//When I am activated this code pieces, I get the output like this
https://www.dropbox.com/s/80uyva56mk1r5xy/Bismillah2.png
/*
StringBuilder sbu = new StringBuilder();
while (true) {
org.antlr.runtime.Token token = lexer.nextToken();
if (token.getType() == Antlr3JavaLexer.EOF) {
break;
}
sbu.append(token.getType());
System.out.println(token.getType() + ": :" + token.getText());
}*/
final CommonTokenStream tokens = new CommonTokenStream();
tokens.setTokenSource(lexer);
tokens.LT(10); // force load
// Create the parser
Antlr3JavaParser parser = new Antlr3JavaParser(tokens);
StringBuffer sb = new StringBuffer();
sb.append(tokens.toString());
DefaultTableModel model = (DefaultTableModel) Main_Menu.jTable2.getModel();
List<final_tugas_akhir.Report2> theListData = new ArrayList<Report2>();
final_tugas_akhir.Report2 theResult = new final_tugas_akhir.Report2();
theResult.setFile(filePath);
theResult.setId(sb.toString());
theResult.setNum(sbu.toString());
theListData.add(theResult);
for (Report2 report : theListData) {
System.out.println(report.getFile());
System.out.println(report.getId());
model.addRow(new Object[]{
report.getFile(),
report.getId(),
report.getNum(),
});
}
// in CompilationUnit
CommonTree tree;
try {
tree = (CommonTree) parser.compilationUnit().getTree();
DOTTreeGenerator gen = new DOTTreeGenerator();
StringTemplate st = gen.toDOT(tree);
} catch (RecognitionException e) {
e.printStackTrace();
return false;
}
walkThroughChildren(tree, treeContainer, parser.getTokenStream()); //this is my method to check the similiar tokens
in.close();
this.posisiFix(treeContainer); //fix position
return true;
}
Once again, this is the error code my java program link: https://www.dropbox.com/s/80uyva56mk1r5xy/Bismillah2.png.
The tokens always give me a null value.

Android/Java - How to retrieve image from web service and show it

I'm using some services of a web service which usually returns JSON respones, but one service when I send the ID of a user returns a static GIF image (Not animated).
The procedure that I'm doing is:
1.Connect to web service using DefaultHttpClient
2.Convert the InputStream received to a String with this utilitary method:
public static String inputStreamToStringScanner(InputStream in) {
Scanner fileScanner = new Scanner(in);
StringBuilder inputStreamString = new StringBuilder();
while(fileScanner.hasNextLine())
inputStreamString.append(fileScanner.nextLine()).append("\n");
fileScanner.close();
return inputStreamString.toString();
}
3.Storage the converted received String to process the server response.
For the Image Service, when I see the string converted, it begins like this:
"GIF89a?��?�� ..."
It's a static GIF file.
I'm not being able to show the image in a ImageView, I have tried different things that I found in the web:
public void onPhotoFinished (String responseData) {
InputStream is = new ByteArrayInputStream(responseData.getBytes());
Bitmap bm = BitmapFactory.decodeStream(is);
userImage.setImageBitmap(bm);
}
This is something else that I have also tried:
public void onPhotoFinished (String responseData) {
InputStream is = new ByteArrayInputStream(responseData.getBytes());
final Bitmap bm = BitmapFactory.decodeStream(new BufferedInputStream(is));
userImage.setImageBitmap(bm);
}
This also doesn't works:
public void onPhotoFinished (String responseData) {
InputStream is = new ByteArrayInputStream(responseData.getBytes());
Drawable d = Drawable.createFromStream(is, "src name");
userImage.setImageDrawable(d);
}
Finally, this doesn't work either:
public void onPhotoFinished (String responseData) {
Bitmap bm = BitmapFactory.decodeByteArray(responseData.getBytes(), 0, responseData.getBytes().length);
userImage.setImageBitmap(bm);
}
In Logcat I receive "decoder->decode returned false"
Nothing seems to work... any ideas of what is wrong?
Thanks!

Finally, I resolved it with FlushedInputStream and using directly the Input Stream, avoiding the conversion to String:
static class FlushedInputStream extends FilterInputStream {
public FlushedInputStream(InputStream inputStream) {
super(inputStream);
}
#Override
public long skip(long n) throws IOException {
long totalBytesSkipped = 0L;
while (totalBytesSkipped < n) {
long bytesSkipped = in.skip(n - totalBytesSkipped);
if (bytesSkipped == 0L) {
int byteReaded = read();
if (byteReaded < 0) {
break;
} else {
bytesSkipped = 1;
}
}
totalBytesSkipped += bytesSkipped;
}
return totalBytesSkipped;
}
}
AND:
Bitmap bitmapResponseData = BitmapFactory.decodeStream(new FlushedInputStream(is));
Regards