I want to read the stdout of a process right as it is generated. The process will send information for a progress indicator, so it doesn't make sense that I get the information all at once, which I do and which is the problem. I tried to use Scanner class as suggested in a post, but I still get the output only after the process has finished. I realize this question has been asked before, but it hasn't been answered.
You will probably want to look at class StreamGobblerOutput first.
public List<String> executeCall(String fileName)
{
StringBuilder sbOutput = new StringBuilder();
StringBuilder sbError = new StringBuilder();
File file = new File(fileName);
try ( BufferedReader br = new BufferedReader(new FileReader(file)) ) {
String line;
while ((line = br.readLine()) != null) {
String [] parts = line.split("\\s");
if(parts.length<2) {
sbError.append("Command too short for call: " + parts[0]);
continue;
}
List<String> args = new ArrayList<String>();
args.add ("sfb.exe");
for(int i = 1; i <parts.length; ++i) {
args.add (parts[i]);
}
args.add (sfbPassword);
ProcessBuilder pb = new ProcessBuilder (args);
pb.directory(new File(Support.getJustThePathFromFile(file)));
Map<String, String> envs = pb.environment();
String path = envs.get("Path");
envs.put("Path", Paths.get(".").toAbsolutePath().normalize().toString() + ";" +path);
//pb.redirectOutput(new Redirect() {});
Process p = pb.start();
String outputPathPrefix = pb.directory().getCanonicalPath();
// any output?
StreamGobblerOutput outputGobbler = new StreamGobblerOutput(p.getInputStream(), outputPathPrefix);
outputGobbler.start();
// any errors?
StreamGobblerError errorGobbler = new StreamGobblerError(p.getErrorStream());
errorGobbler.start();
try
{
p.waitFor();
}
catch (InterruptedException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
sbOutput = outputGobbler.getOutput();
sbError = errorGobbler.getErrors();
String rootPath= Support.getJustThePathFromFile(new File(fileName));
File rootFile = new File(rootPath + "/..");
String rootFolder = rootFile.getCanonicalFile().getName();
System.err.println("rootFolder: " + rootFolder);
mainApp.addModifiedFiles(outputGobbler.getModifiedFileNames(), rootFolder);
}
} catch ( IOException ex) {
sbError.append(ex.getMessage());
}
mainApp.addOutput(sbOutput.toString());
mainApp.addError(sbError.toString());
return;
}
private class StreamGobblerOutput extends Thread {
private InputStream is;
private String outputPathPrefix;
private StringBuilder sbOutput;
private List<String> modifiedFileNames;
private Scanner scanner;
private StreamGobblerOutput(InputStream is, String outputPathPrefix) {
this.is = is;
this.outputPathPrefix = outputPathPrefix;
sbOutput = new StringBuilder();
modifiedFileNames = new ArrayList<String>();
scanner = new Scanner(is);
}
public StringBuilder getOutput() {
return sbOutput;
}
public List<String> getModifiedFileNames() {
return modifiedFileNames;
}
@Override
public void run() {
//create pattern
Pattern patternProgress = Pattern.compile("\\((\\d+)%\\)");
//InputStreamReader isr = new InputStreamReader(is);
//BufferedReader br = new BufferedReader(isr);
String ligne = null;
while (scanner.hasNextLine()) {
ligne = scanner.nextLine();
sbOutput.append(ligne);
sbOutput.append("\r\n");
//bw.write("\r\n");
Matcher mProgress = patternProgress.matcher(ligne);
if (mProgress.find()) {
int percentage = Integer.parseInt(mProgress.group(1));
System.err.println("percentage=" + percentage);
mainApp.mainWindowController.setProgressExecute(percentage/100.0);
}
}
mainApp.mainWindowController.setProgressExecute(1.0);
if (scanner != null) {
scanner.close();
}
}
}
private class StreamGobblerError extends Thread {
private InputStream is;
private StringBuilder sbError;
private Scanner scanner;
private StreamGobblerError(InputStream is) {
this.is = is;
sbError = new StringBuilder();
scanner = new Scanner(is);
}
public StringBuilder getErrors() {
return sbError;
}
@Override
public void run() {
//InputStreamReader isr = new InputStreamReader(is);
//BufferedReader br = new BufferedReader(isr);
String ligne = null;
while (scanner.hasNextLine()) {
ligne = scanner.nextLine();
sbError.append(ligne);
sbError.append("\r\n");
}
if (scanner != null) {
scanner.close();
}
}
}
Update: I tried redirecting the output to a file and reading from it, but it appears this runs into the same buffering problem as the previous implementation: I get only two data points.
As a workaround, I will have to ask the creator of the .exe to include 4100 extra characters in each line showing the progress.
