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Command line terminal executing on process and input interaction from this process [duplicate]

This question already has answers here:
run interactive command line application from java
(2 answers)
Closed 6 years ago.
Basically, I have a process which runs when I press a button on my java application.
And this process executes a command to the terminal of the OS.
But sometimes this command needs to have an interaction with the user.
And I would like to know if this was possible to have the interaction from the process to the user when needed?
My code:
File marsSimulator = new File("resources/mars_simulator/Mars4_5.jar");
if(marsSimulator.exists() && temp.exists()){
String res="";
try {
Process p = Runtime.getRuntime().exec(new String[]{"java","-jar",marsSimulator.getAbsolutePath(),tempAssembly.getAbsolutePath()});
p.waitFor();
InputStream is = p.getInputStream();
byte b[] = new byte[is.available()];
is.read(b, 0, b.length); // probably try b.length-1 or -2 to remove "new-line(s)"
res = new String(b);
} catch (Exception ex) {
ex.printStackTrace();
}
}
Also, I forgot to say that the application is made with SWING and that the output of the process is shown onto a TextArea... Should I change anything ?
Notice that the process blocks when there is an interaction with the user. If there isn't, the process doesn't block !
What do I need to do in this case (which I don't know how to do it ) ?
When the process needs the interaction. I need to know when the process wants some interaction.
I need to get the output generated of the process interactively (line by line).
P.S.: For people who wanna understand the process line, I am using the Mars Simulator (http://courses.missouristate.edu/KenVollmar/MARS/) and I am sending the jar application into a process with a mips assembly code associated.
This next pieces of code is working with my project
Hope it will help for the next adventurers!
And thank you to Nicolas Filotto for helping me.
My class ObservableStream:
class ObservableStream extends Observable {
private final Queue<String> lines = new ConcurrentLinkedQueue<>();
public void addLine(String line) {
lines.add(line);
setChanged();
notifyObservers();
}
public String nextLine() {
return lines.poll();
}
public String getLine(){return lines.peek();}
}
And the other part of the code:
Process p = Runtime.getRuntime().exec(new String[]{"java","-jar",marsSimulator.getAbsolutePath(),tempAssembly.getAbsolutePath()});
//This code does the interaction from the process with the GUI ! Implied, input interaction+output interaction from the process
ObservableStream out = new ObservableStream();
// Observer that simply sends to my external process line by line what we put in
// the variable output
PrintWriter writer = new PrintWriter(p.getOutputStream(), true);
out.addObserver(
(o, arg) -> {
ObservableStream stream = (ObservableStream) o;
String line;
while ((line = stream.nextLine()) != null) {
writer.println(line);
}
}
);
ObservableStream input = new ObservableStream();
input.addObserver(
(o, arg) -> {
ObservableStream stream = (ObservableStream) o;
String line;
while ((line = stream.nextLine()) != null) {
outputTextArea.appendText(line+"\n");
}
}
);
// The thread that reads the standard output stream of the external process
// and put the lines into my variable input
new Thread(
() -> {
try (BufferedReader reader = new BufferedReader(
new InputStreamReader(p.getInputStream()))
) {
String line;
while ((line = reader.readLine()) != null) {
input.addLine(line);
}
} catch (IOException e1) {
e1.printStackTrace();
}
}
).start();
new Thread(
()->{
while(p.isAlive()){
String res = input.getLine();
if(res!=null && res.equals("Enter integer value:")) {
boolean integerIsRequested=true;
Thread t=null;
while(integerIsRequested){
if(t==null) {
t = new Thread(new Runnable() {
public void run() {
String test1 = JOptionPane.showInputDialog("Enter Integer value:");
while(!test1.matches("^\\d+$")){
test1 = JOptionPane.showInputDialog("Error: Not a valid Integer.\nEnter a correct Integer value:");
}
Integer i = Integer.valueOf(test1);
if (i != null) {
out.addLine(test1);
}
}
});
t.start();
}
if(!t.isAlive()){
integerIsRequested=false;
}
}
}
}
outputTextArea.appendText("Program executed\n");
}
).start();
By the way, this post is unique Jarrod ;)

To implement such use case I would personally use:
An Observable object to notify my UI when a new line has been provided by the external process
An Observable object to which I add new lines provided by my UI
An Observer of #1 that will refresh the data of my UI
An Observer of #2 that will send the lines provided by my UI to my external process
A Thread that will check if a new line has been provided by my external process and if so it will provide those lines to #1
So as I don't have your full env, I will show you how it will work with mock objects:
First my fake external application that only does an Echo of what he receives:
public class Echo {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
while (true) {
String line = scanner.nextLine();
System.out.printf("echo > %s%n", line);
}
}
}
If this class receives foo, it will print into the standard output stream echo > foo
Then my Observable class
public class ObservableStream extends Observable {
private final Queue<String> lines = new ConcurrentLinkedQueue<>();
public void addLine(String line) {
lines.add(line);
setChanged();
notifyObservers();
}
public String nextLine() {
return lines.poll();
}
}
NB: The class ObservableStream (as it is implemented so far) is meant to have only one Observer no more which is enough according to your needs. Indeed is only used to decouple your UI from how the data is retrieved or published
Then finally the main code:
Process p = Runtime.getRuntime().exec(
new String[]{"java", "-cp", "/my/path/to/my/classes", "Echo"}
);
// The Observable object allowing to get the input lines from my external process
ObservableStream input = new ObservableStream();
// A mock observer that simply prints the lines provided by the external process
// but in your case you will update your text area instead
input.addObserver(
(o, arg) -> {
ObservableStream stream = (ObservableStream) o;
String line;
while ((line = stream.nextLine()) != null) {
System.out.printf("Line Received from the external process: %s%n", line);
}
}
);
// The thread that reads the standard output stream of the external process
// and put the lines into my variable input
new Thread(
() -> {
try (BufferedReader reader = new BufferedReader(
new InputStreamReader(p.getInputStream()))
) {
String line;
while ((line = reader.readLine()) != null) {
input.addLine(line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
).start();
// The Observable object allowing to send the input lines to my external process
ObservableStream output = new ObservableStream();
// Observer that simply sends to my external process line by line what we put in
// the variable output
PrintWriter writer = new PrintWriter(p.getOutputStream(), true);
output.addObserver(
(o, arg) -> {
ObservableStream stream = (ObservableStream) o;
String line;
while ((line = stream.nextLine()) != null) {
writer.println(line);
}
}
);
// A simple scanner used to send new messages to my external process
Scanner scanner = new Scanner(System.in);
while (true) {
output.addLine(scanner.nextLine());
}
If this code receives foo, it will print into the standard output stream Line Received from the external process: echo > foo

I hope it answers your question... subProcessStuff "emulates" that sub process. It can be anything - but this way we have all in place. It requires 2 params passed into console. String and Integer. Gobbler got Callback which is an interface, with anonymous implementation - and there are checks for params. To answer if subprocess waits we simply track what is says - just like if a user would operate with it.
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.Scanner;
class Test1 {
public static void main(String[] args) {
for (String arg : args)
System.out.println("arg: " + arg);
for (String arg : args)
if (arg.equals("-test")) {
subProcessStuff();
return;
}
mainProcess();
}
public static void subProcessStuff() {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
try {
System.out.println("Enter String");
String s = br.readLine();
System.out.println("Enered String: " + s);
System.out.println("Enter Integer:");
int i = Integer.parseInt(br.readLine());
System.out.println("Entered Integer: " + i);
} catch (IOException e) {
System.err.println("io error - " + e.getMessage());
} catch (NumberFormatException nfe) {
System.err.println("Invalid Format!");
}
}
private static PrintStream out;
public static void mainProcess() {
String[] commands = { "ls", "-alt" };
ProcessBuilder builder = new ProcessBuilder("java", "Test1", "-test");
// builder.inheritIO(); // I avoid this. It was messing me up.
try {
Process proc = builder.start();
InputStream errStream = proc.getErrorStream();
InputStream inStream = proc.getInputStream();
OutputStream outStream = proc.getOutputStream();
new Thread(new StreamGobbler("err", out, errStream)).start();
out = new PrintStream(new BufferedOutputStream(outStream));
Callback cb = new Callback() {
#Override
public void onNextLine(String line) {
if (line.equals("Enter String")) {
out.println("aaaaa");
out.flush();
}
if (line.equals("Enter Integer:")) {
out.println("123");
out.flush();
}
}
};
new Thread(new StreamGobbler("in", out, inStream, cb)).start();
int errorCode = proc.waitFor();
System.out.println("error code: " + errorCode);
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
if (out != null) {
out.close();
}
}
}
}
interface Callback {
void onNextLine(String line);
}
class StreamGobbler implements Runnable {
private PrintStream out;
private Scanner inScanner;
private String name;
private Callback cb;
public StreamGobbler(String name, PrintStream out, InputStream inStream) {
this.name = name;
this.out = out;
inScanner = new Scanner(new BufferedInputStream(inStream));
}
public StreamGobbler(String name, PrintStream out, InputStream inStream, Callback cb) {
this.name = name;
this.out = out;
inScanner = new Scanner(new BufferedInputStream(inStream));
this.cb = cb;
}
#Override
public void run() {
while (inScanner.hasNextLine()) {
String line = inScanner.nextLine();
if (cb != null)
cb.onNextLine(line);
System.out.printf("%s: %s%n", name, line);
}
}
}

I don't think you can check the state of the process from the Java. However you can do it by using some Linux command. (Of course if you're using Linux)
If your Java process has access to the /proc directory then you can read the status file for the process.
For example for a process with process id 12280
/proc/12280/status
Here's the relevant output of the status file
Name: java
State: S (sleeping)
Tgid: 12280
Pid: 12280
PPid: 12279
...
Second line gives the state of the process. You'll need to run a thread to continuously poll this file to read the status.

Line by Line The Code i use to interract with a different jar which is a speechRecognizer.I think you want to achieve something like this.
Example:
The jar i am interracting(speechRecognizer) is executing different commands and run some other Threads.Every time it has to interract with the main jar it prints something that i need.For example (user said:How are you),so you can have a same logic and when external jar need interraction with user it prints something and you read it into the main app.So:
// About Process
private Process process;
private BufferedReader bufferedReader;
private boolean stopped = true;
Thread processChecker;
//Running it in a Thread so the app don't lags
new Thread(() -> {
try {
stopped = false;
//Starting the external jar..
ProcessBuilder builder = new ProcessBuilder("java", "-jar", System.getProperty("user.home")
+ File.separator + "Desktop" + File.separator + "speechRecognizer.jar", "BITCH_PLEASE");
//Redirecting the ErrorStream
builder.redirectErrorStream(true);
process = builder.start();
bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line;
//Check continusly if the process is still alive
//i case of crash i should do something..
processChecker = new Thread(() -> {
while (process.isAlive()) {
try {
Thread.sleep(1200);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
stopSpeechReader(false);
});
processChecker.start();
// Continuesly Read Output of external process
while (!stopped) {
while ((line = bufferedReader.readLine()) != null && !line.isEmpty()) {
System.out.println(line);
checkSpeechResult(line);
}
}
// Interrupt the mf Thread if is Alive
if (processChecker.isAlive())
processChecker.interrupt();
System.out.println("SpeechReader Stopped! Process is alive:" + process.isAlive() + " >Exit Value:"
+ process.exitValue());
} catch (Exception e) {
e.printStackTrace();
}
}).start();

open an application during runtime in Mac OSX using netbeans

I want to open an application during run time in Mac using netbeans i used the following code but it throws exception. I used this code for windows with few changes i used it in Mac. Can anyone pls suggest me the correct code.
else
{
try {
Runtime r = Runtime.getRuntime();
p = Runtime.getRuntime().exec("/Applications/TextEdit.app /Users/apple/Documents/java files/scratch files/hi.rtf");
A4 a4sObj = new A4(new String[]{jComboBox2.getSelectedItem().toString()});
} catch (IOException ex) {
Logger.getLogger(serialportselection.class.getName()).log(Level.SEVERE, null, ex);
}
}

Okay, so that took a little bit of digging. It seems the preferred way to run a .app bundle is to use the open command. In order to get the app to open a file, you have to use the -a parameter, for example...
import java.io.IOException;
import java.io.InputStream;
public class Test {
public static void main(String[] args) {
String cmd = "/Applications/TextEdit.app";
//String cmd = "/Applications/Sublime Text 2.app";
String fileToEdit = "/Users/.../Documents/Test.txt";
System.out.println("Cmd = " + cmd);
ProcessBuilder pb = new ProcessBuilder("open", "-a", cmd, fileToEdit);
pb.redirectErrorStream(true);
try {
Process p = pb.start();
Thread t = new Thread(new InputStreamConsumer(p.getInputStream()));
t.start();
int exitCode = p.waitFor();
t.join();
System.out.println("Exited with " + exitCode);
} catch (IOException | InterruptedException ex) {
ex.printStackTrace();
}
}
public static class InputStreamConsumer implements Runnable {
private InputStream is;
public InputStreamConsumer(InputStream is) {
this.is = is;
}
#Override
public void run() {
int read = -1;
try {
while ((read = is.read()) != -1) {
System.out.print((char)read);
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}

Run exe by java Process, get error code 109

Process p = Runtime.getRuntime().exec("myexe.exe");
BufferedReader br = null;
try{
br = new BufferedReader(new InputStreamReader(p.getInputStream(), "GB2312"));
String value = null;
while ((line = br.readLine()) != null) {
System.out.println(line);
}
}finally{
IOUtils.close(br);
}
Then, the output likes below, not the string I want:
Child: Can't read length for data, error code 109

It seems that the problem appears, because of the output of the exe which is too long. Can ProcessBuilder solve it ?
As a general rule of thumb, you should always read the output of Process before you call waitFor (or use a background Thread to read it while you waitFor)
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
public class PBDemo {
public static void main(String[] args) throws Exception {
String s;
ProcessBuilder pb = new ProcessBuilder("myexe.exe");
pb.redirectErrorStream(true);
try {
Process pro = pb.start();
InputConsumer ic = new InputConsumer(pro.getInputStream());
System.out.println("...Waiting");
int exitCode = pro.waitFor();
ic.join();
System.out.println("Process exited with " + exitCode);
} catch (Exception e) {
System.out.println("sorry" + e);
e.printStackTrace();
}
}
public static class InputConsumer extends Thread {
private InputStream is;
public InputConsumer(InputStream is) {
this.is = is;
start();
}
#Override
public void run() {
try {
int in = -1;
while ((in = is.read()) != -1) {
System.out.print((char) in);
}
} catch (IOException exp) {
exp.printStackTrace();
}
}
}
}
In the past, I've either provided an Observer Pattern to the InputConsumer, through which some other party can be notified as new input comes in or otherwised cached the output so I can process it after the process has completed, based on your needs

getRuntime().exec() does nothing

I want a java program to execute the following shell command:
apktool.jar d /path/to/my/app.apk
This command perfectly works when executing it directly on command line.
Java Code:
public static void main(String[] args) {
String command = "apktool d /path/to/my/app.apk";
try {
Runtime.getRuntime().exec(command);
} catch (IOException e1) {
e1.printStackTrace();
}
}
There is no error, no exception. Nothing happens and i have the impression that I already searched the entire internet for a solution. Does anybody know what I am doing wrong? A simple command like
mkdir /path/to/a/new/folder
works without problems.
I tried the same using ProcessBuilder:
try {
Process process = new ProcessBuilder(command).start();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
This time i only get "Cannot run program "apktool d /path/to/my/app.apk, No such file or directory". I can't even run the mkdir command.

You need to call the jar with java.exe, and you're not doing that. Also you need to trap the input and error streams from the process, something you can't do the way you're running this. Use ProcessBuilder instead, get your streams and then run the process.
For example (and I can only do a Windows example),
import java.io.IOException;
import java.io.InputStream;
import java.util.Scanner;
public class ProcessEg {
private static Process p;
public static void main(String[] args) {
String[] commands = {"cmd", "/c", "dir"};
ProcessBuilder pBuilder = new ProcessBuilder(commands);
pBuilder.redirectErrorStream();
try {
p = pBuilder.start();
InputStream in = p.getInputStream();
final Scanner scanner = new Scanner(in);
new Thread(new Runnable() {
public void run() {
while (scanner.hasNextLine()) {
System.out.println(scanner.nextLine());
}
scanner.close();
}
}).start();
} catch (IOException e) {
e.printStackTrace();
}
try {
int result = p.waitFor();
p.destroy();
System.out.println("exit result: " + result);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}

Try doing it like this:
StringBuffer output = new StringBuffer();
Process p;
try {
p = Runtime.getRuntime().exec("./path/apktool d /path/to/my/app.apk");
p.waitFor();
BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = "";
while ((line = reader.readLine())!= null) {
output.append(line + "\n");
}
} catch (Exception e) {
e.printStackTrace();
}
system.out.println(output.toString());
Creating first a process allows you to wait for a response and reads the output of the execution of your process.
If something is failing while running your shell command, you will have the error printed at the end.
Also, make sure your java program can access your shell script, or better provide the full path to it like:
./path/to/shell/apktool d /path/to/my/app.apk

reading output of a child process Interruptibly

I want to launch a child proces and read its output until EOF or until an internal flag is cleared.
My first attempt was to call InputStream.close() in another thread, but although it works for sockets, it doesn't work with the result of Process.getInputStream(): the main thread is still waiting in read() and the killer thread either hangs in close0() (windows) or continues with no effect (linux).
Then I tried to check InputStream.available(), but it doesn't detect EOF: it returns 0.
public class BbbTest extends TestCase {
private Process proc;
private InputStream getStream() throws IOException {
//if ("".length() == 0) return new java.net.Socket("intra", 80).getInputStream();
String[] cmd;
if (System.getProperty("os.name").toLowerCase().startsWith("windows")) {
cmd = new String[] { "cmd", "/c", "more & more" };
} else {
cmd = new String[] { "sh", "-c", "cat; cat" };
}
Process proc = Runtime.getRuntime().exec(cmd);
return proc.getInputStream();
}
public void testB() throws Exception {
final InputStream in = getStream();
final Thread readingThread = Thread.currentThread();
Thread t = new Thread("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx") {
#Override
public void run() {
try {
sleep(1000);
if (proc != null) proc.destroy(); // this won't help
readingThread.interrupt(); // this won't help either
in.close(); // this will do nothing and may even hang
} catch (RuntimeException e) {
throw e;
} catch (Exception e) {
throw new RuntimeException ( );
}
}
};
t.setDaemon(true);
t.start();
try {
in.read();
assertTrue(false);
} catch (IOException e) {
// nothing
}
}
}
My last hope is to steal the channel from the returned stream and use nio

In windows , this Command will not terminate.
cmd = new String[] { "cmd", "/c", "more & more" };
Instead of try this simple command
cmd = new String[] { "cmd", "/c", "dir" };
And if you want to read your stream
public static void slurp(final InputStream is, final int bufferSize)
{
try(final Reader in = new InputStreamReader(is, "UTF-8");
BufferedReader br = new BufferedReader(in);){
String line;
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
Call this method by passing stream like this.
final BbbTest bbTest = new BbbTest();
Thread t = new Thread("xsdfds") {
#Override
public void run() {
try {
slurp(bbTest.getStream());
} catch (RuntimeException e) {
throw e;
} catch (Exception e) {
throw new RuntimeException ( );
}
}
};
t.start();
If you want to kill the process from child thread.
Create setter and getter method for Process in BbbTest like this
public class BbbTest {
private Process proc;
/**
* #return the proc
*/
public Process getProc() {
return proc;
}
/**
* #param proc the proc to set
*/
public void setProc(Process proc) {
this.proc = proc;
}
private InputStream getStream() throws IOException {
String[] cmd;
if (System.getProperty("os.name").toLowerCase().startsWith("windows")) {
// cmd = new String[] { "cmd", "/c", "more & more" };
cmd = new String[] { "cmd", "/c", "dir" };
} else {
cmd = new String[] { "sh", "-c", "cat; cat" };
}
proc = Runtime.getRuntime().exec(cmd);
return proc.getInputStream();
}
}
Now using process you can destroy
bbTest.getProc().destroy();
If you want to kill the process based on output of other stream, you can add logic in slurp method by checking line content and terminate using destroy
UPDATE
Simple Demo
public class BbbTest {
private Process startProcess(String[] commands) throws IOException {
Process proc = Runtime.getRuntime().exec(commands);
return proc;
}
public static void slurp(final InputStream is)
{
try(final Reader in = new InputStreamReader(is, "UTF-8");
BufferedReader br = new BufferedReader(in);){
String line;
while ((line = br.readLine()) != null) {
System.out.println(line);
if (line.equals("end")){
break;
}
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String args[]) throws Exception {
final BbbTest bbTest = new BbbTest();
final Process process = bbTest.startProcess(new String[] { "cmd", "/c", "more" });
Thread t = new Thread("xsdfds") {
#Override
public void run() {
try {
slurp(process.getInputStream());
process.destroy();
} catch (RuntimeException e) {
throw e;
} catch (Exception e) {
throw new RuntimeException ( );
}
}
};
t.start();
try(OutputStream out = process.getOutputStream();
BufferedOutputStream outStream = new BufferedOutputStream(out);){
outStream.write("Test".getBytes());
outStream.write("\n".getBytes());
outStream.write("end".getBytes());
outStream.write("\n".getBytes());
outStream.flush();
}
}
}
Look at this sample : You should have some condition to terminate the child thread ( reading prcoess) like if the stream writes "end" / or End of EOF ( process closed inputstream )