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Last modified by Pascal Robert on 2012/08/11 18:16
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Pascal Robert 6.1 1 = The Project Wonder way =
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Pascal Robert 7.1 3 Project Wonder, in the ERExtensions framework, have a utility class to help you run command-line applications, [[ERXRuntimeUtilities>>url:http://jenkins.wocommunity.org/job/Wonder/javadoc/er/extensions/foundation/ERXRuntimeUtilities.html||shape="rect"]]. This utility class is used inside Wonder, for example ERAttachment use it to call ImageMagick when you want to resize images.
Pascal Robert 6.1 4
Pascal Robert 7.1 5 Check the Javadoc for the [[execute>>url:http://jenkins.wocommunity.org/job/Wonder/javadoc/er/extensions/foundation/ERXRuntimeUtilities.html#execute||shape="rect"]] method to see examples.
Pascal Robert 6.1 6
7 = The Java way =
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smmccraw 1.1 9 Here, the "cat" and "outputCat" are debugging output categories:
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Quinton Dolan 3.1 11 {{code}}
smmccraw 1.1 12
Quinton Dolan 3.1 13 Process process=null;
14 try {
15 process = Runtime.getRuntime().exec(commandLine);
16 OutputStream output = process.getOutputStream();
17 output.write(inputString.getBytes());
18 output.close();
19 process.waitFor();
20 DataInputStream dis=new DataInputStream(process.getInputStream());
21 String output;
22 do {
23 output = dis.readLine();
24 if (output != null)
25 outputCat.debug(output);
26 } while (output != null);
27 dis.close();
28 } catch (IOException e) {
29 cat.error("IOException: " + e.toString());
30 } catch (InterruptedException e) {
31 cat.error("Interrupted process: " + e.toString());
32 } finally {
33 if (process != null)
34 process.destroy();
35 outputCat.debug("Process finished.");
36 }
smmccraw 1.1 37
Quinton Dolan 3.1 38 {{/code}}
smmccraw 1.1 39
40 Note: A number of people have reported problems with process.waitFor() on Windows. The WebObjects Development List at Omnigroup has a number of people's workaround code for this problem.
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42 **Note 2:** The procedure given here, of course, is to call anything executable from the command line from your Java program, not just Perl scripts.
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Pascal Robert 4.1 44 === Mike Schrag ===
smmccraw 1.1 45
Pascal Robert 7.1 46 process.waitFor() is not just a problem on Windows. This code //will// cause problems. Process maintains buffers for stdout and stderr. If you do not consume those streams, you will run into deadlocks. The proper way to use Runtime.exec is to setup a thread for stderr and a thread for stdout and consume them yourself into your own buffer that does not have the same restrictions that the stock VM has.
smmccraw 1.1 47
Pascal Robert 7.1 48 There's a good example of this technique on [[JavaWorld>>url:http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html||shape="rect"]].