Package org.apache.hadoop.util

Class Shell.ShellCommandExecutor

java.lang.Object

org.apache.hadoop.util.Shell

org.apache.hadoop.util.Shell.ShellCommandExecutor

All Implemented Interfaces:

Shell.CommandExecutor

Enclosing class:

Shell

public static class Shell.ShellCommandExecutor
extends Shell
implements Shell.CommandExecutor

A simple shell command executor. ShellCommandExecutorshould be used in cases where the output of the command needs no explicit parsing and where the command, working directory and the environment remains unchanged. The output of the command is stored as-is and is expected to be small.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.util.Shell

Shell.CommandExecutor, Shell.ExitCodeException, Shell.OSType, Shell.ShellCommandExecutor

Field Summary

Fields inherited from class org.apache.hadoop.util.Shell

ENV_HADOOP_HOME, ENV_NAME_REGEX, FREEBSD, inheritParentEnv, isSetsidAvailable, LINK_COMMAND, LINUX, LOG, MAC, osType, OTHER, PPC_64, READ_LINK_COMMAND, SET_GROUP_COMMAND, SET_OWNER_COMMAND, SET_PERMISSION_COMMAND, SOLARIS, SYSPROP_HADOOP_HOME_DIR, timeOutInterval, TOKEN_SEPARATOR_REGEX, USER_NAME_COMMAND, WINDOWS, WINDOWS_MAX_SHELL_LENGHT, WINDOWS_MAX_SHELL_LENGTH, WindowsProcessLaunchLock, WINUTILS

Constructor Summary

Constructors

Constructor	Description
ShellCommandExecutor(String[] execString)
ShellCommandExecutor(String[] execString, File dir)
ShellCommandExecutor(String[] execString, File dir, Map<String,String> env)
ShellCommandExecutor(String[] execString, File dir, Map<String,String> env, long timeout)
ShellCommandExecutor(String[] execString, File dir, Map<String,String> env, long timeout, boolean inheritParentEnv)	Create a new instance of the ShellCommandExecutor to execute a command.

Method Summary

Modifier and Type	Method	Description
void	close()
void	execute()	Execute the shell command.
String[]	getExecString()	return an array containing the command name and its parameters.
String	getOutput()	Get the output of the shell command.
long	getTimeoutInterval()	Returns the timeout value set for the executor's sub-commands.
protected void	parseExecResult(BufferedReader lines)	Parse the execution result.
String	toString()	Returns the commands of this instance.

Methods inherited from class org.apache.hadoop.util.Shell

appendScriptExtension, appendScriptExtension, bashQuote, checkIsBashSupported, checkWindowsCommandLineLength, destroyAllShellProcesses, execCommand, execCommand, execCommand, getAllShells, getCheckProcessIsAliveCommand, getEnvironment, getEnvironmentVariableRegex, getExitCode, getGetPermissionCommand, getGroupsCommand, getGroupsForUserCommand, getGroupsIDForUserCommand, getHadoopHome, getMemlockLimit, getProcess, getQualifiedBin, getQualifiedBinPath, getReadlinkCommand, getRunScriptCommand, getSetOwnerCommand, getSetPermissionCommand, getSetPermissionCommand, getSignalKillCommand, getSymlinkCommand, getUsersForNetgroupCommand, getWaitingThread, getWinUtilsFile, getWinUtilsPath, hasWinutilsPath, isJava7OrAbove, isJavaVersionAtLeast, isTimedOut, run, setEnvironment, setWorkingDirectory

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.util.Shell.CommandExecutor

getExitCode

Constructor Details

ShellCommandExecutor

public ShellCommandExecutor(String[] execString)

ShellCommandExecutor

public ShellCommandExecutor(String[] execString,
 File dir)

ShellCommandExecutor

public ShellCommandExecutor(String[] execString,
 File dir,
 Map<String,String> env)

ShellCommandExecutor

public ShellCommandExecutor(String[] execString,
 File dir,
 Map<String,String> env,
 long timeout)

ShellCommandExecutor

public ShellCommandExecutor(String[] execString,
 File dir,
 Map<String,String> env,
 long timeout,
 boolean inheritParentEnv)

Create a new instance of the ShellCommandExecutor to execute a command.

Parameters:

execString - The command to execute with arguments

dir - If not-null, specifies the directory which should be set as the current working directory for the command. If null, the current working directory is not modified.

env - If not-null, environment of the command will include the key-value pairs specified in the map. If null, the current environment is not modified.

timeout - Specifies the time in milliseconds, after which the command will be killed and the status marked as timed-out. If 0, the command will not be timed out.

inheritParentEnv - Indicates if the process should inherit the env vars from the parent process or not.

Method Details

getTimeoutInterval

@VisibleForTesting
public long getTimeoutInterval()

Returns the timeout value set for the executor's sub-commands.

Returns:

The timeout value in milliseconds

execute

public void execute()
             throws IOException

Execute the shell command.

Specified by:

execute in interface Shell.CommandExecutor

Throws:

IOException - if the command fails, or if the command is not well constructed.

getExecString

public String[] getExecString()

Description copied from class: Shell

return an array containing the command name and its parameters.

Specified by:

getExecString in class Shell

Returns:

exec string array.

parseExecResult

protected void parseExecResult(BufferedReader lines)
                        throws IOException

Description copied from class: Shell

Parse the execution result.

Specified by:

parseExecResult in class Shell

Parameters:

lines - lines.

Throws:

IOException - raised on errors performing I/O.

getOutput

public String getOutput()

Get the output of the shell command.

Specified by:

getOutput in interface Shell.CommandExecutor

toString

public String toString()

Returns the commands of this instance. Arguments with spaces in are presented with quotes round; other arguments are presented raw

Overrides:

toString in class Object

Returns:

a string representation of the object.

close

public void close()

Specified by:

close in interface Shell.CommandExecutor