|
||||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Objectorg.apache.hadoop.util.Shell
public abstract class Shell
A base class for running a Unix command.
Shell
can be used to run unix commands like du
or
df
. It also offers facilities to gate commands by
time-intervals.
Nested Class Summary | |
---|---|
static class |
Shell.ExitCodeException
This is an IOException with exit code added. |
static class |
Shell.ShellCommandExecutor
A simple shell command executor. |
Field Summary | |
---|---|
static org.apache.commons.logging.Log |
LOG
|
static java.lang.String |
SET_GROUP_COMMAND
|
static java.lang.String |
SET_OWNER_COMMAND
a Unix command to set owner |
static java.lang.String |
SET_PERMISSION_COMMAND
a Unix command to set permission |
static java.lang.String |
USER_NAME_COMMAND
a Unix command to get the current user's name |
static boolean |
WINDOWS
Set to true on Windows platforms |
Constructor Summary | |
---|---|
Shell()
|
|
Shell(long interval)
|
Method Summary | |
---|---|
static java.lang.String |
execCommand(java.util.Map<java.lang.String,java.lang.String> env,
java.lang.String... cmd)
Static method to execute a shell command. |
static java.lang.String |
execCommand(java.lang.String... cmd)
Static method to execute a shell command. |
protected abstract java.lang.String[] |
getExecString()
return an array containing the command name & its parameters |
int |
getExitCode()
get the exit code |
static java.lang.String[] |
getGET_PERMISSION_COMMAND()
Return a Unix command to get permission information. |
static java.lang.String[] |
getGROUPS_COMMAND()
a Unix command to get the current user's groups list |
java.lang.Process |
getProcess()
get the current sub-process executing the given command |
static java.lang.String[] |
getUlimitMemoryCommand(Configuration conf)
Get the Unix command for setting the maximum virtual memory available to a given child process. |
protected abstract void |
parseExecResult(java.io.BufferedReader lines)
Parse the execution result |
protected void |
run()
check to see if a command needs to be executed and execute if needed |
protected void |
setEnvironment(java.util.Map<java.lang.String,java.lang.String> env)
set the environment for the command |
protected void |
setWorkingDirectory(java.io.File dir)
set the working directory |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
---|
public static final org.apache.commons.logging.Log LOG
public static final java.lang.String USER_NAME_COMMAND
public static final java.lang.String SET_PERMISSION_COMMAND
public static final java.lang.String SET_OWNER_COMMAND
public static final java.lang.String SET_GROUP_COMMAND
public static final boolean WINDOWS
Constructor Detail |
---|
public Shell()
public Shell(long interval)
interval
- the minimum duration to wait before re-executing the
command.Method Detail |
---|
public static java.lang.String[] getGROUPS_COMMAND()
public static java.lang.String[] getGET_PERMISSION_COMMAND()
public static java.lang.String[] getUlimitMemoryCommand(Configuration conf)
Mapper
or the
Reducer
implementations
e.g. Hadoop Pipes
or Hadoop Streaming.
It also checks to ensure that we are running on a *nix platform else
(e.g. in Cygwin/Windows) it returns null
.
conf
- configuration
String[]
with the ulimit command arguments or
null
if we are running on a non *nix platform or
if the limit is unspecified.protected void setEnvironment(java.util.Map<java.lang.String,java.lang.String> env)
env
- Mapping of environment variablesprotected void setWorkingDirectory(java.io.File dir)
dir
- The directory where the command would be executedprotected void run() throws java.io.IOException
java.io.IOException
protected abstract java.lang.String[] getExecString()
protected abstract void parseExecResult(java.io.BufferedReader lines) throws java.io.IOException
java.io.IOException
public java.lang.Process getProcess()
public int getExitCode()
public static java.lang.String execCommand(java.lang.String... cmd) throws java.io.IOException
Shell
interface.
cmd
- shell command to execute.
java.io.IOException
public static java.lang.String execCommand(java.util.Map<java.lang.String,java.lang.String> env, java.lang.String... cmd) throws java.io.IOException
Shell
interface.
env
- the map of environment key=valuecmd
- shell command to execute.
java.io.IOException
|
||||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |