On Oct 17, 2007, at 5:40 PM, Doug Zwick wrote:
it waits for the osascript command to complete.
Also, note that the above is not production-quality code. Whenever
one uses Runtime.exec one should always spawn two threads to drain
the stout and stderr streams, *especially* when calling
Process.waitFor. Failure to do so will result in a deadlock if the
process generates more than a couple of hundred bytes of output.
I think the draining thing might depend on ordering as well. If a
process does not deadlock without two threads it probably never
will. I have simple Runtime exec code and more complicated where
the deadlock is a concern. The simple can usually just be inserted
as a method in a the class...
e.g.
public boolean isExecutable(String execpath) {
String[] rtargs = new String[] { "ls","-al",execpath };
String lsout = rtexec(rtargs);
String executable = lsout.substring(3,4);
return executable.equals("x");
}
public boolean setExecutable(String executable) {
String[] rtargs = new String[] { "chmod","555",executable };
String chmodout = rtexec(rtargs);
return isExecutable(executable);
}
private String rtexec(String[] args) {
try {
StringBuffer execout = new StringBuffer();
Process proc = Runtime.getRuntime().exec(args);
proc.waitFor();
InputStream inout = proc.getInputStream();
InputStream inerr = proc.getErrorStream();
byte []buffer = new byte[256];
while (true) {
int stderrLen = inerr.read(buffer, 0, buffer.length);
if (stderrLen > 0) {
execout.append(new String(buffer,0,stderrLen));
// out.write(buffer, 0, stderrLen);
}
int stdoutLen = inout.read(buffer, 0, buffer.length);
if (stdoutLen > 0) {
// out.write(buffer, 0, stdoutLen);
execout.append(new String(buffer,0,stdoutLen));
}
if (stderrLen < 0 && stdoutLen < 0)
break;
}
return execout.toString();
}
catch(Throwable tossed) { tossed.printStackTrace(); }
return "-";
}
You can also get more interactive with Runtime'd osascript if you
want. The following is from a java CLI GUI shell. It feeds
osascript the input through it's System.in and gets the output from
the appropriate stream as well.
osascript
set cd to (random number 100000) mod 52 + 1
return cd
18 Oct 2007 06:29:23,375 INFO - RuntimeExecutable: osascript
18 Oct 2007 06:29:23,379 INFO - -s
18 Oct 2007 06:29:23,379 INFO - s
18 Oct 2007 06:29:23,380 INFO - -e
18 Oct 2007 06:29:23,380 INFO - set cd to (random
number 100000) mod 52 + 1
return cd
49
Since the parms get echoed I might be wrong on this feeding the
script to osascript through System.in. It probably accumulates them
and sends the entire script as a parameter. However, I think I have
entered scripts into Terminal using osascript's system in so that
should work.
The 49 is the returned result, so this is not completely async anyhow.
Also java alone, even if the process is async, should be able to
wait as long as you might want and check for the existence of files.
Mike Hall hallmike at att dot net
http://www.geocities.com/mik3hall
http://sourceforge.net/projects/macnative
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