org.apache.commons.exec

Interface Executor

All Known Implementing Classes:

DaemonExecutor, DefaultExecutor

public interface Executor

The main abstraction to start an external process. The interface allows to

• set a current working directory for the subprocess
• provide a set of environment variables passed to the subprocess
• capture the subprocess output of stdout and stderr using an ExecuteStreamHandler
• kill long-running processes using an ExecuteWatchdog
• define a set of expected exit values
• terminate any started processes when the main process is terminating using a ProcessDestroyer

The following example shows the basic usage:

 Executor exec = new DefaultExecutor();
 CommandLine cl = new CommandLine("ls -l");
 int exitvalue = exec.execute(cl);
 

Field Summary

Fields

Modifier and Type	Field and Description
static int	INVALID_EXITVALUE Invalid exit code.

Method Summary

Modifier and Type	Method and Description
int	execute(CommandLine command) Methods for starting synchronous execution.
void	execute(CommandLine command, ExecuteResultHandler handler) Methods for starting asynchronous execution.
int	execute(CommandLine command, java.util.Map<java.lang.String,java.lang.String> environment) Methods for starting synchronous execution.
void	execute(CommandLine command, java.util.Map<java.lang.String,java.lang.String> environment, ExecuteResultHandler handler) Methods for starting asynchronous execution.
ProcessDestroyer	getProcessDestroyer() Set the handler for cleanup of started processes if the main process is going to terminate.
ExecuteStreamHandler	getStreamHandler() Get the StreamHandler used for providing input and retrieving the output.
ExecuteWatchdog	getWatchdog() Get the watchdog used to kill of processes running, typically, too long time.
java.io.File	getWorkingDirectory() Get the working directory of the created process.
boolean	isFailure(int exitValue) Checks whether exitValue signals a failure.
void	setExitValue(int value) Define the exitValue of the process to be considered successful.
void	setExitValues(int[] values) Define a list of exitValue of the process to be considered successful.
void	setProcessDestroyer(ProcessDestroyer processDestroyer) Get the handler for cleanup of started processes if the main process is going to terminate.
void	setStreamHandler(ExecuteStreamHandler streamHandler) Set a custom the StreamHandler used for providing input and retrieving the output.
void	setWatchdog(ExecuteWatchdog watchDog) Set the watchdog used to kill of processes running, typically, too long time.
void	setWorkingDirectory(java.io.File dir) Set the working directory of the created process.

Field Detail

INVALID_EXITVALUE

static final int INVALID_EXITVALUE

Invalid exit code.

See Also:

Constant Field Values

Method Detail

setExitValue

void setExitValue(int value)

Define the exitValue of the process to be considered successful. If a different exit value is returned by the process then execute(CommandLine) will throw an ExecuteException

Parameters:

value - the exit code representing successful execution

setExitValues

void setExitValues(int[] values)

Define a list of exitValue of the process to be considered successful. The caller can pass one of the following values

• an array of exit values to be considered successful
• an empty array for auto-detect of successful exit codes relying on isFailure(int)
• null to indicate to skip checking of exit codes

If an undefined exit value is returned by the process then execute(CommandLine) will throw an ExecuteException.

Parameters:

values - a list of the exit codes

isFailure

boolean isFailure(int exitValue)

Checks whether exitValue signals a failure. If no exit values are set than the default conventions of the OS is used. e.g. most OS regard an exit code of '0' as successful execution and everything else as failure.

Parameters:

exitValue - the exit value (return code) to be checked

Returns:

true if exitValue signals a failure

getStreamHandler

ExecuteStreamHandler getStreamHandler()

Get the StreamHandler used for providing input and retrieving the output.

Returns:

the StreamHandler

setStreamHandler

void setStreamHandler(ExecuteStreamHandler streamHandler)

Set a custom the StreamHandler used for providing input and retrieving the output. If you don't provide a proper stream handler the executed process might block when writing to stdout and/or stderr (see Process).

Parameters:

streamHandler - the stream handler

getWatchdog

ExecuteWatchdog getWatchdog()

Get the watchdog used to kill of processes running, typically, too long time.

Returns:

the watchdog

setWatchdog

void setWatchdog(ExecuteWatchdog watchDog)

Set the watchdog used to kill of processes running, typically, too long time.

Parameters:

watchDog - the watchdog

getProcessDestroyer

ProcessDestroyer getProcessDestroyer()

Set the handler for cleanup of started processes if the main process is going to terminate.

Returns:

the ProcessDestroyer

setProcessDestroyer

void setProcessDestroyer(ProcessDestroyer processDestroyer)

Get the handler for cleanup of started processes if the main process is going to terminate.

Parameters:

processDestroyer - the ProcessDestroyer

getWorkingDirectory

java.io.File getWorkingDirectory()

Get the working directory of the created process.

Returns:

the working directory

setWorkingDirectory

void setWorkingDirectory(java.io.File dir)

Set the working directory of the created process. The working directory must exist when you start the process.

Parameters:

dir - the working directory

execute

int execute(CommandLine command)
     throws ExecuteException,
            java.io.IOException

Methods for starting synchronous execution. The child process inherits all environment variables of the parent process.

Parameters:

command - the command to execute

Returns:

process exit value

Throws:

ExecuteException - execution of subprocess failed or the subprocess returned a exit value indicating a failure setExitValue(int).

java.io.IOException

execute

int execute(CommandLine command,
            java.util.Map<java.lang.String,java.lang.String> environment)
     throws ExecuteException,
            java.io.IOException

Methods for starting synchronous execution.

Parameters:

command - the command to execute

environment - The environment for the new process. If null, the environment of the current process is used.

Returns:

process exit value

Throws:

ExecuteException - execution of subprocess failed or the subprocess returned a exit value indicating a failure setExitValue(int).

java.io.IOException

execute

void execute(CommandLine command,
             ExecuteResultHandler handler)
      throws ExecuteException,
             java.io.IOException

Methods for starting asynchronous execution. The child process inherits all environment variables of the parent process. Result provided to callback handler.

Parameters:

command - the command to execute

handler - capture process termination and exit code

Throws:

ExecuteException - execution of subprocess failed

java.io.IOException

execute

void execute(CommandLine command,
             java.util.Map<java.lang.String,java.lang.String> environment,
             ExecuteResultHandler handler)
      throws ExecuteException,
             java.io.IOException

Methods for starting asynchronous execution. The child process inherits all environment variables of the parent process. Result provided to callback handler.

Parameters:

command - the command to execute

environment - The environment for the new process. If null, the environment of the current process is used.

handler - capture process termination and exit code

Throws:

ExecuteException - execution of subprocess failed

java.io.IOException