3 * This class can be used to execute a system command from a Java application.
4 * See the documentation for the public methods of this class for more
7 * Documentation for this class is available at this URL:
9 * http://devdaily.com/java/java-processbuilder-process-system-exec
12 * Copyright 2010 alvin j. alexander, devdaily.com.
14 * This program is free software: you can redistribute it and/or modify it under
15 * the terms of the GNU Lesser Public License as published by the Free Software
16 * Foundation, either version 3 of the License, or (at your option) any later
19 * This program is distributed in the hope that it will be useful, but WITHOUT
20 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
21 * FOR A PARTICULAR PURPOSE. See the GNU Lesser Public License for more details.
23 * You should have received a copy of the GNU Lesser Public License along with
24 * this program. If not, see <http://www.gnu.org/licenses/>.
26 * Please ee the following page for the LGPL license:
27 * http://www.gnu.org/licenses/lgpl.txt
31 package org.forester.util;
34 import java.io.IOException;
35 import java.io.InputStream;
36 import java.io.OutputStream;
37 import java.util.List;
39 public class SystemCommandExecutor {
41 private final List<String> commandInformation;
42 private final String adminPassword;
43 private ThreadedStreamHandler inputStreamHandler;
44 private ThreadedStreamHandler errorStreamHandler;
47 * Pass in the system command you want to run as a List of Strings, as shown here:
49 * List<String> commands = new ArrayList<String>();
50 * commands.add("/sbin/ping");
53 * commands.add("www.google.com");
54 * SystemCommandExecutor commandExecutor = new SystemCommandExecutor(commands);
55 * commandExecutor.executeCommand();
57 * Note: I've removed the other constructor that was here to support executing
58 * the sudo command. I'll add that back in when I get the sudo command
59 * working to the point where it won't hang when the given password is
62 * @param commandInformation The command you want to run.
64 public SystemCommandExecutor( final List<String> commandInformation ) {
65 if ( ( commandInformation == null ) || commandInformation.isEmpty() ) {
66 throw new IllegalArgumentException( "The commandInformation is required." );
68 checkCmdFile( new File( commandInformation.get( 0 ) ) );
69 this.commandInformation = commandInformation;
73 public static boolean isExecuteableFile( final File path_to_cmd_f ) {
74 if ( !path_to_cmd_f.exists() ) {
77 else if ( path_to_cmd_f.isDirectory() ) {
80 else if ( !path_to_cmd_f.canExecute() ) {
86 private void checkCmdFile( final File path_to_cmd_f ) {
87 if ( !path_to_cmd_f.exists() ) {
88 throw new IllegalArgumentException( "[" + path_to_cmd_f.getAbsolutePath() + "] does not exist" );
90 else if ( path_to_cmd_f.isDirectory() ) {
91 throw new IllegalArgumentException( "[" + path_to_cmd_f.getAbsolutePath() + "] is a directory" );
93 else if ( !path_to_cmd_f.canExecute() ) {
94 throw new IllegalArgumentException( "[" + path_to_cmd_f.getAbsolutePath() + "] is not executeable" );
98 public int executeCommand() throws IOException, InterruptedException {
101 final ProcessBuilder pb = new ProcessBuilder( commandInformation );
102 final Process process = pb.start();
103 // you need this if you're going to write something to the command's input stream
104 // (such as when invoking the 'sudo' command, and it prompts you for a password).
105 final OutputStream stdOutput = process.getOutputStream();
106 // i'm currently doing these on a separate line here in case i need to set them to null
107 // to get the threads to stop.
108 // see http://java.sun.com/j2se/1.5.0/docs/guide/misc/threadPrimitiveDeprecation.html
109 final InputStream inputStream = process.getInputStream();
110 final InputStream errorStream = process.getErrorStream();
111 // these need to run as java threads to get the standard output and error from the command.
112 // the inputstream handler gets a reference to our stdOutput in case we need to write
113 // something to it, such as with the sudo command
114 inputStreamHandler = new ThreadedStreamHandler( inputStream, stdOutput, adminPassword );
115 errorStreamHandler = new ThreadedStreamHandler( errorStream );
116 // TODO the inputStreamHandler has a nasty side-effect of hanging if the given password is wrong; fix it
117 inputStreamHandler.start();
118 errorStreamHandler.start();
119 // TODO a better way to do this?
120 exitValue = process.waitFor();
121 // TODO a better way to do this?
122 inputStreamHandler.interrupt();
123 errorStreamHandler.interrupt();
124 inputStreamHandler.join();
125 errorStreamHandler.join();
127 catch ( final IOException e ) {
128 // TODO deal with this here, or just throw it?
131 catch ( final InterruptedException e ) {
132 // generated by process.waitFor() call
133 // TODO deal with this here, or just throw it?
142 * Get the standard error (stderr) from the command you just exec'd.
144 public StringBuilder getStandardErrorFromCommand() {
145 return errorStreamHandler.getOutputBuffer();
149 * Get the standard output (stdout) from the command you just exec'd.
151 public StringBuilder getStandardOutputFromCommand() {
152 return inputStreamHandler.getOutputBuffer();