org.iges.grads.server
Class Task

java.lang.Object
  |
  +--org.iges.grads.server.Task

public class Task

extends java.lang.Object

A wrapper for invoking an external process.

Field Summary

protected java.lang.String[]	cmd
protected java.lang.String	cmdString
protected java.lang.String[]	env
protected static java.lang.String	ERROR_INDICATOR String that subprocesses can print to indicate to the server that an error has occurred in their processing.
protected java.lang.StringBuffer	output
protected long	timeLimit
protected java.io.File	workDir

Constructor Summary

Task(java.lang.String[] cmd, java.lang.String[] env, java.io.File workDir, long timeLimit)
Sets up an external process.

Method Summary

protected java.lang.String	buildCmdString(java.lang.String[] cmd) Turns an array of Strings into a single space-separated String
protected void	checkErrors() Parses output looking for error messages, defined as lines beginning with the string contained in ERROR_INDICATOR (currently "error: ").
protected void	finish(java.lang.Process process, long startTime) Waits for a running process to complete (or time out), and then performs cleanup and error-handling tasks.
java.lang.String	getCmd() Returns a printable string version of the external command.
java.lang.String	getOutput() Returns a string version of the command's console output
void	run() Executes the external process, returning when it is finished or when it exceeds the time limit specified in the constructor.
void	run(long timeLimit) Executes the external process, returning when it is finished or when it exceeds the time limit specified.

Methods inherited from class java.lang.Object

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

Field Detail

ERROR_INDICATOR

protected static java.lang.String ERROR_INDICATOR

String that subprocesses can print to indicate to the server that an error has occurred in their processing.

output

protected java.lang.StringBuffer output

cmdString

protected java.lang.String cmdString

cmd

protected java.lang.String[] cmd

env

protected java.lang.String[] env

workDir

protected java.io.File workDir

timeLimit

protected long timeLimit

Constructor Detail

Task

public Task(java.lang.String[] cmd,
            java.lang.String[] env,
            java.io.File workDir,
            long timeLimit)

Sets up an external process.

Method Detail

run

public void run()
         throws AnagramException

Executes the external process, returning when it is finished or when it exceeds the time limit specified in the constructor.

Throws:

AnagramException - If the process fails, or if the output parser finds an error message in the output.

run

public void run(long timeLimit)
         throws AnagramException

Executes the external process, returning when it is finished or when it exceeds the time limit specified.

Parameters:

timeLimit - Overrides the time limit specified in the constructor.

Throws:

AnagramException - If the process fails, or if there is an error message (a line beginning with "error: ") in the output.

getCmd

public java.lang.String getCmd()

Returns a printable string version of the external command.

getOutput

public java.lang.String getOutput()

Returns a string version of the command's console output

buildCmdString

protected java.lang.String buildCmdString(java.lang.String[] cmd)

Turns an array of Strings into a single space-separated String

finish

protected void finish(java.lang.Process process,
                      long startTime)
               throws AnagramException

Waits for a running process to complete (or time out), and then performs cleanup and error-handling tasks.

AnagramException

checkErrors

protected void checkErrors()
                    throws AnagramException

Parses output looking for error messages, defined as lines beginning with the string contained in ERROR_INDICATOR (currently "error: "). The remainder of the line is treated as an error message to pass to the user.

Throws:

AnagramException - if a line containing an error message is found.