prod/net/jaekl/cfb/util/Command.java

   1 package net.jaekl.cfb.util;
   2
   3 // Copyright (C) 2015 Christian Jaekl
   4
   5 import java.io.BufferedReader;
   6 import java.io.IOException;
   7 import java.io.InputStream;
   8 import java.io.InputStreamReader;
   9
  10 public class Command {
  11         public static class Result
  12         {
  13                 private int m_retCode;
  14                 private String m_stdout;
  15                 private String m_stderr;
  16
  17                 Result(int retCode, String stdout, String stderr) {
  18                         m_retCode = retCode;
  19                         m_stdout = stdout;
  20                         m_stderr = stderr;
  21                 }
  22
  23                 public int getRetCode() { return m_retCode; }
  24                 public String getStdout() { return m_stdout; }
  25                 public String getStderr() { return m_stderr; }
  26         }
  27
  28         private static class StreamGobbler extends Thread {
  29
  30                 private StringBuilder m_sb;
  31                 private BufferedReader m_br;
  32
  33                 public StreamGobbler(InputStream is) {
  34                         m_sb = new StringBuilder();
  35                         m_br = new BufferedReader(new InputStreamReader(is));
  36                 }
  37
  38                 @Override
  39                 public void run() {
  40                         String line;
  41                         try {
  42                                 line = m_br.readLine();
  43                                 while (null != line) {
  44                                         m_sb.append(line).append(System.lineSeparator());
  45                                         line = m_br.readLine();
  46                                 }
  47                         } catch (IOException exc) {
  48                                 m_sb.append(Util.stringify(exc));
  49                         }
  50                         finally {
  51                                 try {
  52                                         m_br.close();
  53                                 } catch (IOException exc) {
  54                                         m_sb.append(Util.stringify(exc));
  55                                 }
  56                         }
  57                 }
  58
  59                 public String getOutput() { return m_sb.toString(); }
  60         }
  61
  62         public Command()
  63         {
  64                 // no-op
  65         }
  66
  67         public Result exec(String cmd) throws IOException
  68         {
  69                 int retCode = 0;
  70                 String stdout = "";
  71                 String stderr = "";
  72
  73                 Process proc = doRuntimeExec(cmd);
  74                 assert( null != proc );
  75
  76                 StreamGobbler stdoutGobbler = new StreamGobbler(proc.getInputStream());
  77                 StreamGobbler stderrGobbler = new StreamGobbler(proc.getErrorStream());
  78
  79                 stdoutGobbler.start();
  80                 stderrGobbler.start();
  81
  82                 try {
  83                         retCode = proc.waitFor();
  84                         stdoutGobbler.join();
  85                         stderrGobbler.join();
  86
  87                         stdout = stdoutGobbler.getOutput();
  88                         stderr = stdoutGobbler.getOutput();
  89
  90                 } catch (InterruptedException exc) {
  91                         stderr += Util.stringify(exc);
  92                 }
  93
  94                 return new Result(retCode, stdout, stderr);
  95         }
  96
  97         Process doRuntimeExec(String cmd) throws IOException {
  98                 return Runtime.getRuntime().exec(cmd);
  99         }
 100 }