Package org.jppf.node.protocol

Class CommandLineTask<T>

java.lang.Object

org.jppf.node.protocol.AbstractTask<T>

org.jppf.node.protocol.CommandLineTask<T>

Type Parameters:

T - the type of results returned by this task.

All Implemented Interfaces:

Serializable, Runnable, EventListener, Interruptibility, PositionalElement<Task<T>>, Task<T>, ProcessWrapperEventListener

public abstract class CommandLineTask<T>
extends AbstractTask<T>
implements ProcessWrapperEventListener

Instances of this class encapsulate the execution of an external process, program or shell script.
This task starts and external process using command line arguments, environment variables, and a list of input and/or output files to use or generated by the external process.
This task also captures the standard and error output (i.e. equivalent to System.out and System.err) of the external process.

Author:

Laurent Cohen

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
CommandLineTask()	Default constructor.
CommandLineTask(String... commands)	Create an instance of this class and set the parameters of the external process or script to launch.
CommandLineTask(Map<String,String> env, String startDir, String... commands)	Create an instance of this class and set the parameters of the external process or script to launch.

Method Summary

Modifier and Type	Method	Description
void	errorStreamAltered(ProcessWrapperEvent event)	Notification that the process has written to its error stream.
List<String>	getCommandList()	Get the list of command-line arguments.
Map<String,String>	getEnv()	Get the environment variables to set.
String	getErrorOutput()	Get the content of the error output for the process.
int	getExitCode()	Get the exit code returned by the sub-process.
Process	getProcess()	Get the process that is launched by this task.
String	getStandardOutput()	Get the content of the standard output for the process.
String	getStartDir()	Get the directory to start the command in.
boolean	isCaptureOutput()	Determines whether the process output is captured.
int	launchProcess()	Run the external process or script.
void	outputStreamAltered(ProcessWrapperEvent event)	Notification that the process has written to its output stream.
CommandLineTask<T>	setCaptureOutput(boolean captureOutput)	Specifies whether the process output is captured.
CommandLineTask<T>	setCommandList(String... commands)	Set the list of command-line arguments.
CommandLineTask<T>	setCommandList(List<String> commandList)	Set the list of command-line arguments.
CommandLineTask<T>	setEnv(Map<String,String> env)	Get the environment variables to set.
CommandLineTask<T>	setStartDir(String startDir)	Set the directory to start the command in.

Methods inherited from class org.jppf.node.protocol.AbstractTask

compute, fireNotification, getDataProvider, getId, getJob, getMaxResubmits, getNode, getPosition, getResult, getTaskClassLoader, getTaskObject, getThrowable, getTimeoutSchedule, isInNode, isInterruptible, isResubmit, onCancel, onTimeout, run, setDataProvider, setExecutionDispatcher, setId, setInNode, setJob, setMaxResubmits, setNode, setPosition, setResubmit, setResult, setThrowable, setTimeoutSchedule

Methods inherited from class java.lang.Object

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

Constructor Details

CommandLineTask

public CommandLineTask()

Default constructor.

CommandLineTask

public CommandLineTask(String... commands)

Create an instance of this class and set the parameters of the external process or script to launch.

Parameters:

commands - the list of command-line arguments.

CommandLineTask

public CommandLineTask(Map<String,String> env,
 String startDir,
 String... commands)

Create an instance of this class and set the parameters of the external process or script to launch.

Parameters:

env - the environment variables to set.

startDir - the directory to start the command in.

commands - the list of command-line arguments.

Method Details

launchProcess

public int launchProcess()
                  throws Exception

Run the external process or script.

Returns:

the exit code returned by the sub-process.

Throws:

Exception - if an error occurs.

isCaptureOutput

public boolean isCaptureOutput()

Determines whether the process output is captured.

Returns:

true if the output is captured, false otherwise.

setCaptureOutput

public CommandLineTask<T> setCaptureOutput(boolean captureOutput)

Specifies whether the process output is captured.

Parameters:

captureOutput - true if the output is captured, false otherwise.

Returns:

this task, for method chaining.

getStandardOutput

public String getStandardOutput()

Get the content of the standard output for the process.

Returns:

the output as a string.

getErrorOutput

public String getErrorOutput()

Get the content of the error output for the process.

Returns:

the output as a string.

getCommandList

public List<String> getCommandList()

Get the list of command-line arguments.

Returns:

a list of arguments as strings.

setCommandList

public CommandLineTask<T> setCommandList(List<String> commandList)

Set the list of command-line arguments.

Parameters:

commandList - a list of arguments as strings.

Returns:

this task, for method chaining.

setCommandList

public CommandLineTask<T> setCommandList(String... commands)

Set the list of command-line arguments.

Parameters:

commands - a list of arguments as strings.

Returns:

this task, for method chaining.

getEnv

public Map<String,String> getEnv()

Get the environment variables to set.

Returns:

a map of variable names to their corresponding values.

setEnv

public CommandLineTask<T> setEnv(Map<String,String> env)

Get the environment variables to set.

Parameters:

env - a map of variable names to their corresponding values.

Returns:

this task, for method chaining.

getStartDir

public String getStartDir()

Get the directory to start the command in.

Returns:

the start directory as a string.

setStartDir

public CommandLineTask<T> setStartDir(String startDir)

Set the directory to start the command in.

Parameters:

startDir - the start directory as a string.

Returns:

this task, for method chaining.

outputStreamAltered

public void outputStreamAltered(ProcessWrapperEvent event)

Notification that the process has written to its output stream.

Specified by:

outputStreamAltered in interface ProcessWrapperEventListener

Parameters:

event - encapsulates the output stream's content.

errorStreamAltered

public void errorStreamAltered(ProcessWrapperEvent event)

Notification that the process has written to its error stream.

Specified by:

errorStreamAltered in interface ProcessWrapperEventListener

Parameters:

event - encapsulate the error stream's content.

getExitCode

public int getExitCode()

Get the exit code returned by the sub-process.

Returns:

the value of the exit code returned by the sub-process. A negative value indicates the process was never launched or never returned.

getProcess

public Process getProcess()

Get the process that is launched by this task.

Returns:

a Process instance.