org.apache.hadoop.mapreduce
Class Counters

java.lang.Object
  org.apache.hadoop.mapreduce.Counters

All Implemented Interfaces:

Iterable<CounterGroup>, Writable

public class Counters
extends Object
implements Writable, Iterable<CounterGroup>

Constructor Summary

Counters()

Counters(Counters counters)

Method Summary

int	countCounters() Returns the total number of counters, by summing the number of counters in each group.
boolean	equals(Object genericRight)
Counter	findCounter(Enum<?> key) Find the counter for the given enum.
Counter	findCounter(String groupName, String counterName)
CounterGroup	getGroup(String groupName) Returns the named counter group, or an empty group if there is none with the specified name.
Collection<String>	getGroupNames() Returns the names of all counter classes.
int	hashCode()
void	incrAllCounters(Counters other) Increments multiple counters by their amounts in another Counters instance.
Iterator<CounterGroup>	iterator()
void	readFields(DataInput in) Read a set of groups.
String	toString() Return textual representation of the counter values.
void	write(DataOutput out) Write the set of groups.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Counters

public Counters()

Counters

public Counters(Counters counters)

Method Detail

findCounter

public Counter findCounter(String groupName,
                           String counterName)

findCounter

public Counter findCounter(Enum<?> key)

Find the counter for the given enum. The same enum will always return the same counter.

Parameters:

key - the counter key

Returns:

the matching counter object

getGroupNames

public Collection<String> getGroupNames()

Returns the names of all counter classes.

Returns:

Set of counter names.

iterator

public Iterator<CounterGroup> iterator()

Specified by:

iterator in interface Iterable<CounterGroup>

getGroup

public CounterGroup getGroup(String groupName)

Returns the named counter group, or an empty group if there is none with the specified name.

countCounters

public int countCounters()

Returns the total number of counters, by summing the number of counters in each group.

write

public void write(DataOutput out)
           throws IOException

Write the set of groups. The external format is: #groups (groupName group)* i.e. the number of groups followed by 0 or more groups, where each group is of the form: groupDisplayName #counters (false | true counter)* where each counter is of the form: name (false | true displayName) value

Specified by:

write in interface Writable

Parameters:

out - DataOuput to serialize this object into.

Throws:

IOException

readFields

public void readFields(DataInput in)
                throws IOException

Read a set of groups.

Specified by:

readFields in interface Writable

Parameters:

in - DataInput to deseriablize this object from.

Throws:

IOException

toString

public String toString()

Return textual representation of the counter values.

Overrides:

toString in class Object

incrAllCounters

public void incrAllCounters(Counters other)

Increments multiple counters by their amounts in another Counters instance.

Parameters:

other - the other Counters instance

equals

public boolean equals(Object genericRight)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object