Package org.apache.hadoop.fs

Class CachingGetSpaceUsed

java.lang.Object

org.apache.hadoop.fs.CachingGetSpaceUsed

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, GetSpaceUsed

Direct Known Subclasses:

DFCachingGetSpaceUsed, DU, WindowsGetSpaceUsed

@LimitedPrivate({"HDFS","MapReduce"})
@Evolving
public abstract class CachingGetSpaceUsed
extends java.lang.Object
implements java.io.Closeable, GetSpaceUsed

Interface for class that can tell estimate much space is used in a directory.

The implementor is fee to cache space used. As such there are methods to update the cached value with any known changes.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.fs.GetSpaceUsed

GetSpaceUsed.Builder

Field Summary

Fields

Modifier and Type	Field	Description
protected java.util.concurrent.atomic.AtomicLong	used

Constructor Summary

Constructors

Constructor	Description
CachingGetSpaceUsed(GetSpaceUsed.Builder builder)	This is the constructor used by the builder.

Method Summary

Modifier and Type	Method	Description
void	close()
java.lang.String	getDirPath()
long	getJitter()	Randomize the refresh interval timing by this amount, the actual interval will be chosen uniformly between interval-jitter and interval+jitter.
long	getRefreshInterval()	How long in between runs of the background refresh.
long	getUsed()
void	incDfsUsed(long value)	Increment the cached value of used space.
protected abstract void	refresh()
protected void	setShouldFirstRefresh(boolean shouldFirstRefresh)	Reset that if we need to do the first refresh.
protected void	setUsed(long usedValue)	Reset the current used data amount.

Methods inherited from class java.lang.Object

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

Field Detail

used

protected final java.util.concurrent.atomic.AtomicLong used

Constructor Detail

CachingGetSpaceUsed

public CachingGetSpaceUsed(GetSpaceUsed.Builder builder)
                    throws java.io.IOException

This is the constructor used by the builder. All overriding classes should implement this.

Parameters:

builder - builder.

Throws:

java.io.IOException - raised on errors performing I/O.

Method Detail

refresh

protected abstract void refresh()

setShouldFirstRefresh

protected void setShouldFirstRefresh(boolean shouldFirstRefresh)

Reset that if we need to do the first refresh.

Parameters:

shouldFirstRefresh - The flag value to set.

getUsed

public long getUsed()
             throws java.io.IOException

Specified by:

getUsed in interface GetSpaceUsed

Returns:

an estimate of space used in the directory path.

Throws:

java.io.IOException

getDirPath

public java.lang.String getDirPath()

Returns:

The directory path being monitored.

incDfsUsed

public void incDfsUsed(long value)

Increment the cached value of used space.

Parameters:

value - dfs used value.

getRefreshInterval

@VisibleForTesting
public long getRefreshInterval()

How long in between runs of the background refresh.

Returns:

refresh interval.

getJitter

@VisibleForTesting
public long getJitter()

Randomize the refresh interval timing by this amount, the actual interval will be chosen uniformly between interval-jitter and interval+jitter.

Returns:

between interval-jitter and interval+jitter.

setUsed

protected void setUsed(long usedValue)

Reset the current used data amount. This should be called when the cached value is re-computed.

Parameters:

usedValue - new value that should be the disk usage.

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.io.Closeable

Throws:

java.io.IOException