Package org.apache.hadoop.fs.shell

Class Truncate

java.lang.Object

org.apache.hadoop.conf.Configured

org.apache.hadoop.fs.shell.Command

org.apache.hadoop.fs.shell.FsCommand

org.apache.hadoop.fs.shell.Truncate

All Implemented Interfaces:

Configurable

@Private
@Unstable
public class Truncate
extends FsCommand

Truncates a file to a new size

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DESCRIPTION
static final String	NAME
protected long	newLength
static final String	USAGE
protected List<PathData>	waitList
protected boolean	waitOpt

Fields inherited from class org.apache.hadoop.fs.shell.Command

args, COMMAND_DESCRIPTION_FIELD, COMMAND_NAME_FIELD, COMMAND_USAGE_FIELD, err, exceptions, exitCode, name, numErrors, out, recursive

Constructor Summary

Constructors

Constructor	Description
Truncate()

Method Summary

Modifier and Type	Method	Description
protected void	processArguments(LinkedList<PathData> args)	Processes the command's list of expanded arguments.
protected void	processOptions(LinkedList<String> args)	Must be implemented by commands to process the command line flags and check the bounds of the remaining arguments.
protected void	processPath(PathData item)	Hook for commands to implement an operation to be applied on each path for the command.
static void	registerCommands(CommandFactory factory)

Methods inherited from class org.apache.hadoop.fs.shell.FsCommand

getCommandName, processRawArguments, run, runAll

Methods inherited from class org.apache.hadoop.fs.shell.Command

displayError, displayError, displayWarning, exitCodeForError, expandArgument, expandArguments, getCommandFactory, getDepth, getDescription, getListingGroupSize, getName, getReplacementCommand, getUsage, isDeprecated, isPathRecursable, isRecursive, isSorted, postProcessPath, processArgument, processNonexistentPath, processPathArgument, processPaths, processPaths, recursePath, run, run, setCommandFactory, setName, setRecursive

Methods inherited from class org.apache.hadoop.conf.Configured

getConf, setConf

Methods inherited from class java.lang.Object

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

Field Details

NAME

public static final String NAME

See Also:

• Constant Field Values

USAGE

public static final String USAGE

See Also:

• Constant Field Values

DESCRIPTION

public static final String DESCRIPTION

See Also:

• Constant Field Values

newLength

protected long newLength

waitList

protected List<PathData> waitList

waitOpt

protected boolean waitOpt

Constructor Details

Truncate

public Truncate()

Method Details

registerCommands

public static void registerCommands(CommandFactory factory)

processOptions

protected void processOptions(LinkedList<String> args)
                       throws IOException

Description copied from class: Command

Must be implemented by commands to process the command line flags and check the bounds of the remaining arguments. If an IllegalArgumentException is thrown, the FsShell object will print the short usage of the command.

Overrides:

processOptions in class Command

Parameters:

args - the command line arguments

Throws:

IOException - raised on errors performing I/O.

processArguments

protected void processArguments(LinkedList<PathData> args)
                         throws IOException

Description copied from class: Command

Processes the command's list of expanded arguments. Command.processArgument(PathData) will be invoked with each item in the list. The loop catches IOExceptions, increments the error count, and displays the exception.

Overrides:

processArguments in class Command

Parameters:

args - a list of PathData to process

Throws:

IOException - if anything goes wrong...

processPath

protected void processPath(PathData item)
                    throws IOException

Description copied from class: Command

Hook for commands to implement an operation to be applied on each path for the command. Note implementation of this method is optional if earlier methods in the chain handle the operation.

Overrides:

processPath in class Command

Parameters:

item - a PathData object

Throws:

IOException - if anything else goes wrong in the user-implementation