wamblee.org Git - utils/blob - support/general/src/main/java/org/wamblee/io/SimpleProcess.java

   1 package org.wamblee.io;
   2
   3 import java.io.BufferedReader;
   4 import java.io.File;
   5 import java.io.IOException;
   6 import java.io.InputStream;
   7 import java.io.InputStreamReader;
   8 import java.io.OutputStream;
   9 import java.io.PrintStream;
  10 import java.io.StringWriter;
  11 import java.io.Writer;
  12
  13 import org.apache.commons.logging.Log;
  14 import org.apache.commons.logging.LogFactory;
  15
  16 public class SimpleProcess {
  17
  18         private static final Log LOG = LogFactory.getLog(SimpleProcess.class);
  19
  20         private File _directory;
  21
  22         private String[] _cmd;
  23
  24         private String _stdout;
  25         private String _stderr;
  26
  27         public SimpleProcess(File aDirectory, String[] aCmd) {
  28                 _directory = aDirectory;
  29                 _cmd = aCmd;
  30         }
  31
  32     /**
  33      * @return the stdout
  34      */
  35     public String getStdout() {
  36         return _stdout;
  37     }
  38
  39     /**
  40      * @return the stderr
  41      */
  42     public String getStderr() {
  43         return _stderr;
  44     }
  45
  46         /**
  47          * Runs the process and blocks until it is done.
  48          *
  49          * @return Exit status of the process.
  50          * @throws IOException
  51          *             In case of problems.
  52          */
  53         public int run() throws IOException {
  54                 return runImpl();
  55         }
  56
  57         private int runImpl() throws IOException {
  58                 try {
  59                     String fullcmd = "";
  60                     for (String part: _cmd) {
  61                         fullcmd += " " + part;
  62                     }
  63                         LOG.debug("Executing '" + fullcmd + "' in directory '" + _directory
  64                                         + "'");
  65                         java.lang.Process proc = Runtime.getRuntime().exec(_cmd, null, _directory);
  66
  67                         // Read standard output and error in separate threads to avoid
  68                         // deadlock.
  69
  70             StringWriter stdout = new StringWriter();
  71             StringWriter stderr = new StringWriter();
  72                         Thread stdoutReader = readAndLogStream("STDOUT>  ", proc
  73                                         .getInputStream(), stdout);
  74                         Thread stderrReader = readAndLogStream("STDERR>  ", proc
  75                                         .getErrorStream(), stderr);
  76
  77                         try {
  78                                 proc.waitFor();
  79                         } catch (InterruptedException e) {
  80                                 IOException exception = new IOException(
  81                                                 "Process was terminated: " + this);
  82                                 exception.initCause(e);
  83                                 throw exception;
  84                         }
  85                         waitForReader(stdoutReader);
  86                         waitForReader(stderrReader);
  87
  88             _stdout = stdout.toString();
  89             _stderr = stderr.toString();
  90
  91                         if (proc.exitValue() != 0) {
  92                                 LOG.warn("Exit value was non-zero: " + this);
  93                         } else {
  94                                 LOG.debug("Process finished");
  95                         }
  96                         return proc.exitValue();
  97                 } catch (IOException e) {
  98                         IOException exception = new IOException("Error executing process: "
  99                                         + this);
 100                         exception.initCause(e);
 101                         throw exception;
 102                 }
 103         }
 104
 105         private void waitForReader(Thread aReaderThread) {
 106                 try {
 107                         aReaderThread.join();
 108                 } catch (InterruptedException e) {
 109                         LOG
 110                                         .warn(this
 111                                                         + ": error waiting for output stream reader of process to finish");
 112                 }
 113         }
 114
 115         private Thread readAndLogStream(final String aPrefix,
 116                         final InputStream aStream, final Writer aOutput) {
 117                 Thread inputReader = new Thread() {
 118                         @Override
 119                         public void run() {
 120                                 BufferedReader br = null;
 121                                 try {
 122                                         br = new BufferedReader(new InputStreamReader(aStream));
 123                                         String str;
 124                                         while ((str = br.readLine()) != null) {
 125                                                 LOG.debug(aPrefix + str);
 126                         aOutput.write(str);
 127                                         }
 128                                 } catch (IOException e) {
 129                                         LOG.warn(SimpleProcess.this + ": error reading input stream", e);
 130                                 } finally {
 131                                         if (br != null) {
 132                                                 try {
 133                                                         br.close();
 134                                                 } catch (IOException e) {
 135                                                         LOG.warn("Error closing stream " + aPrefix);
 136                                                 }
 137                                         }
 138                                 }
 139                         }
 140                 };
 141                 inputReader.start();
 142                 return inputReader;
 143         }
 144
 145         @Override
 146         public String toString() {
 147         String fullcmd = "";
 148         for (String part: _cmd) {
 149             fullcmd += part + " ";
 150         }
 151                 return "process(dir = '" + _directory + "', cmd = '" + fullcmd + "')";
 152         }
 153 }