com.day.util

Class ProcessRunner

java.lang.Object

com.day.util.ProcessRunner

All Implemented Interfaces:

java.lang.Runnable

public class ProcessRunner
extends java.lang.Object
implements java.lang.Runnable

The ProcessRunner class helps running external processes. This encompasses redirection of stdin, stdout and stderr as well as optionally waiting for the completion of the process. This implementation is based on the Runtime.exec(String) method and does not yet support passing specific environments or decomposed comand lines.

This class can be used in two ways. If you don't care about waiting for the processes completion and return code, you might do it like this :

Runnable pr = new ProcessRunner("command", null, null, null);
new Thread(pr).start();

If on the other hand you want to capture all output and also keep an eye on the time the process takes to execute (or wait indefinitely), you might use the class like this :

ProcessRunner pr = new ProcessRunner("command", in, out, err);
pr.run(0);
int rc = pr.getReturnCode();

Since:

coati

Field Summary

Fields

Modifier and Type	Field and Description
static int	PROCESS_ABORTED Constant to indicate the process has been aborted
static int	PROCESS_RUNNING Constant to indicate the process is running

Constructor Summary

Constructors

Constructor and Description
ProcessRunner(java.lang.String cmdLine) Creates a new ProcessRunner to execute the given command line containing the command to execute and all relevant command arguments with no redirection of stdin, stdout and stderr.
ProcessRunner(java.lang.String cmdLine, java.io.InputStream stdin, java.io.OutputStream stdout, java.io.OutputStream stderr) Creates a new ProcessRunner to execute the given command line containing the command to execute and all relevant command arguments.

Method Summary

Modifier and Type	Method and Description
int	getReturnCode() Returns the return code from running the command line.
void	run() Runs the process sending the input data and capturing output data.
void	run(long waitTime) Executes the command line and waits for the completion of the prcoess.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PROCESS_RUNNING

public static final int PROCESS_RUNNING

Constant to indicate the process is running

See Also:

Constant Field Values

PROCESS_ABORTED

public static final int PROCESS_ABORTED

Constant to indicate the process has been aborted

See Also:

Constant Field Values

Constructor Detail

ProcessRunner

public ProcessRunner(java.lang.String cmdLine,
                     java.io.InputStream stdin,
                     java.io.OutputStream stdout,
                     java.io.OutputStream stderr)

Creates a new ProcessRunner to execute the given command line containing the command to execute and all relevant command arguments. The stdin InputStream can be used to feed input data to the command executed, while the output (stdout and stderr) are redirected to the given OutputStreams or the process defaults (System.out and System.err, resp.).

None of the streams is closed after running the command line. This is the sole duty of the client of this class.

Parameters:

cmdLine - This commandline is given to the Runtime.exec(String) contains all the command arguments and is split up with a StringTokenizer. See the API docs on the Runtime.exec(String) method for details.

stdin - The InputStream containing data to be handed to the process as stdin. Set this to null if the process should not get any input. This stream is completely read after the process is started and sent to the process. Therefor the stream should be available.

stdout - The OutputStream to send the stdout output of the process to. If this is null, stdout output is written to System.out.

stderr - The OuputStream to send the stderr output of the process to. If this is null, stderr output is written to System.err.

ProcessRunner

public ProcessRunner(java.lang.String cmdLine)

Creates a new ProcessRunner to execute the given command line containing the command to execute and all relevant command arguments with no redirection of stdin, stdout and stderr.

Parameters:

cmdLine - This commandline is given to the Runtime.exec(String) contains all the command arguments and is split up with a StringTokenizer. See the API docs on the Runtime.exec(String) method for details.

Method Detail

run

public void run(long waitTime)

Executes the command line and waits for the completion of the prcoess. The process runs in its own thread which is marked as daemon thread. That is as soon as the Java VM is about to end, the process will also forcibly stopped and does not run to completion.

Parameters:

waitTime - The number of milliseconds to wait for the completion of the process. If the time has ellapsed before the process has terminated, the process will be forcibly terminated. If this value is negative, the process runs completely detached, while a value of zero indicates to wait indeterminate for the completion of the process.

getReturnCode

public int getReturnCode()

Returns the return code from running the command line. As long as the command is running, the method returns PROCESS_RUNNING. After the process has terminated, the method returns the return code from the process or PROCESS_ABORTED if the command has been terminated due to a timeout.

Returns:

The return code from the process or either PROCESS_RUNNING or PROCESS_ABORTED.

run

public void run()

Runs the process sending the input data and capturing output data.

Do not directly call this method. Instead either use new Thread(new ProcessRunner(cmd)).start() or use the run(long) method.

Specified by:

run in interface java.lang.Runnable