org.apache.hadoop.util

Class Shell.ShellCommandExecutor

java.lang.Object

org.apache.hadoop.util.Shell

org.apache.hadoop.util.Shell.ShellCommandExecutor

Enclosing class:

org.apache.hadoop.util.Shell

public static class Shell.ShellCommandExecutor
extends org.apache.hadoop.util.Shell

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.ExitCodeException, Shell.ShellCommandExecutor

Field Summary

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

LINK_COMMAND, LOG, READ_LINK_COMMAND, SET_GROUP_COMMAND, SET_OWNER_COMMAND, SET_PERMISSION_COMMAND, timeOutInterval, USER_NAME_COMMAND, WINDOWS

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
void	execute() Execute the shell command.
String[]	getExecString() return an array containing the command name & its parameters
String	getOutput() Get the output of the shell command.
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

execCommand, execCommand, execCommand, getExitCode, getGET_PERMISSION_COMMAND, getGroupsCommand, getGroupsForUserCommand, getProcess, getUsersForNetgroupCommand, isTimedOut, run, setEnvironment, setWorkingDirectory

Methods inherited from class java.lang.Object

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

Constructor Detail

Shell.ShellCommandExecutor

public Shell.ShellCommandExecutor(String[] execString)

Shell.ShellCommandExecutor

public Shell.ShellCommandExecutor(String[] execString,
                          File dir)

Shell.ShellCommandExecutor

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

Shell.ShellCommandExecutor

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

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 timedout. If 0, the command will not be timed out.

Method Detail

execute

public void execute()
             throws IOException

Execute the shell command.

Throws:

IOException

getExecString

public String[] getExecString()

Description copied from class: org.apache.hadoop.util.Shell

return an array containing the command name & its parameters

Specified by:

getExecString in class org.apache.hadoop.util.Shell

parseExecResult

protected void parseExecResult(BufferedReader lines)
                        throws IOException

Description copied from class: org.apache.hadoop.util.Shell

Parse the execution result

Specified by:

parseExecResult in class org.apache.hadoop.util.Shell

Throws:

IOException

getOutput

public String getOutput()

Get the output of the shell command.

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.