Package org.apache.hadoop.hdfs.server.namenode.top.window

Class RollingWindowManager

java.lang.Object

org.apache.hadoop.hdfs.server.namenode.top.window.RollingWindowManager

@Private
public class RollingWindowManager
extends Object

A class to manage the set of RollingWindows. This class is the interface of metrics system to the RollingWindows to retrieve the current top metrics.

Thread-safety is provided by each RollingWindow being thread-safe as well as ConcurrentHashMap for the collection of them.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	RollingWindowManager.Op	Represents an operation within a TopWindow.
static class	RollingWindowManager.TopWindow	Represents a snapshot of the rolling window.
static class	RollingWindowManager.User	Represents a user who called an Op within a TopWindow.

Field Summary

Fields

Modifier and Type	Field	Description
static final org.slf4j.Logger	LOG
ConcurrentHashMap<String,org.apache.hadoop.hdfs.server.namenode.top.window.RollingWindowManager.RollingWindowMap>	metricMap	A mapping from each reported metric to its RollingWindowManager.RollingWindowMap that maintains the set of RollingWindows for the users that have operated on that metric.

Constructor Summary

Constructors

Constructor	Description
RollingWindowManager(org.apache.hadoop.conf.Configuration conf, int reportingPeriodMs)

Method Summary

Modifier and Type	Method	Description
void	recordMetric(long time, String command, String user, long delta)	Called when the metric command is changed by "delta" units at time "time" via user "user"
RollingWindowManager.TopWindow	snapshot(long time)	Take a snapshot of current top users in the past period.

Methods inherited from class java.lang.Object

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

Field Details

LOG

public static final org.slf4j.Logger LOG

metricMap

public ConcurrentHashMap<String,org.apache.hadoop.hdfs.server.namenode.top.window.RollingWindowManager.RollingWindowMap> metricMap

A mapping from each reported metric to its RollingWindowManager.RollingWindowMap that maintains the set of RollingWindows for the users that have operated on that metric.

Constructor Details

RollingWindowManager

public RollingWindowManager(org.apache.hadoop.conf.Configuration conf,
 int reportingPeriodMs)

Method Details

recordMetric

public void recordMetric(long time,
 String command,
 String user,
 long delta)

Called when the metric command is changed by "delta" units at time "time" via user "user"

Parameters:

time - the time of the event

command - the metric that is updated, e.g., the operation name

user - the user that updated the metric

delta - the amount of change in the metric, e.g., +1

snapshot

public RollingWindowManager.TopWindow snapshot(long time)

Take a snapshot of current top users in the past period.

Parameters:

time - the current time

Returns:

a TopWindow describing the top users for each metric in the window.