Solved

Questions on Runtime.getRuntime()

Posted on 2006-06-30
7
210 Views
Last Modified: 2010-03-31
Guys couple of quick questions on Runtime.getRuntime()

First question ... waitFor?  Is it onyl used for cleanup?  If not for what?
exitCode = p.waitFor();  abnormal termations?


Second question if I want to obtain the output from running an application this way
I know I get via  InputStreamReader and BufferedReader if I was to loop
through the BufferedReader response

while ( (line = br.readLine()) != null)
{
             response=response+line;
}

it would give me all output from the program correct?  (Assuming no abnormal terminations


public static boolean executeObject(byte[] bs)
      {
            boolean resultcode = false;
            String programdir="";
            String programName="";
            String response="";

            
            
            String[] command = new String[2];
            
            
            
            try
            {
                  programdir="D:/ryno71;
                  programName="ryno71.exe";
            } catch (Exception e1)
            {
                  // TODO Auto-generated catch block
                  e1.printStackTrace();
            }
            
            command[0] = programdir+programName;
            String byte_to_string= new String(bs, 0, bs.length);

            command[1] = byte_to_string;  //put what I am executing with ryno71.exe
            //cmd[2] = "param2";
            
            InputStreamReader isr=null;
            BufferedReader br = null;
            try
            {
                  Runtime program = Runtime.getRuntime();
                  Process p = program.exec(command);
                  InputStream stdin = p.getInputStream();
                  
                  
                  
                  
                  try
                  {
                        
                        isr = new InputStreamReader(stdin);
                  }
                  
                  finally
                  {
                        try
                        {
                              if (isr != null) isr.close();
                        }
                        catch(IOException ie)
                        {
                              
                              ie.printStackTrace();
                              
                        };
                        
                        
                  }
                  
                  try
                  {
                        
                        br = new BufferedReader(isr);
                  }
                  
                  finally
                  {
                        
                        try
                        {
                              if (br != null) br.close();
                        }
                        catch(IOException e)
                        {
                              e.printStackTrace();
                              
                        };
                        
                  }
                  
                  String line=null;
                  while ( (line = br.readLine()) != null)
                  {
                                                  response=response+line;
                                                }
                                                //System.out.println(line);
                  
                  //write abnormal out somewhere here.
                  
                  
                  int exitCode = 0;
                  try
                  {
                  exitCode = p.waitFor();  
                                                /*exitCode <= used for errors if you dont want to
                                                     use a separate thread for Process.getErrorStream ?
                                                    Whats waitFor used for????
                                                 */

                  } catch (InterruptedException e)
                  {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                  }
                  if (exitCode != 0)
                  {
                        resultcode=false;
//                        
                        e1.printStackTrace();
                  }
                                                else
                                                {
                                                          resultcode=true;
                                                }

                  
            } catch (IOException e)
            {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
            }
            
            
            return resultcode;
      }

As always thanks for the input
0
Comment
Question by:ryno71
  • 4
  • 3
7 Comments
 
LVL 86

Accepted Solution

by:
CEHJ earned 125 total points
ID: 17018328
>>exitCode = p.waitFor();  abnormal termations?

Normal *and* abnormal

>>it would give me all output from the program correct?

You need to treat the streams on separate threads. See

http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html
0
 

Author Comment

by:ryno71
ID: 17018483
Thanks for the quick response.  If I am limited in opening additional new threads... (not allowed to open additional threads) what I have would work for normal output, correct?
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 17018498
It's difficult to say whether it would work. Try it out
0
Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

 

Author Comment

by:ryno71
ID: 17018507
Would I run into issues if I don't pay attention to the ErrorStream and only worry about the InputStream?
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 17018518
Again it's difficult to say
0
 

Author Comment

by:ryno71
ID: 17019824
thanks nothing abnormal, but might see something if I am playing with large amounts of data.

Have a nice weekend

ryno71
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 17019837
:-)
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Java contains several comparison operators (e.g., <, <=, >, >=, ==, !=) that allow you to compare primitive values. However, these operators cannot be used to compare the contents of objects. Interface Comparable is used to allow objects of a cl…
Go is an acronym of golang, is a programming language developed Google in 2007. Go is a new language that is mostly in the C family, with significant input from Pascal/Modula/Oberon family. Hence Go arisen as low-level language with fast compilation…
Viewers learn about the third conditional statement “else if” and use it in an example program. Then additional information about conditional statements is provided, covering the topic thoroughly. Viewers learn about the third conditional statement …
This theoretical tutorial explains exceptions, reasons for exceptions, different categories of exception and exception hierarchy.

809 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question