com.aliyun.odps.counter

Class Counter

java.lang.Object

com.aliyun.odps.counter.Counter

All Implemented Interfaces:

Writable

public class Counter
extends Object
implements Writable

Counter计数器，可以自定义Counter，用于统计计数，例如统计脏数据记录个数.

Counter相关类的关系：

• Counters 是 CounterGroup 的集合
• CounterGroup 是 Counter 的集合

示例代码：

 public class UserDefinedCounterExample {
   enum MyCounter {
     DIRTY_RECORDS
   }

   public static class MyMapper extends Mapper<Text, Text> {
     Counter counter;

     protected void setup(MapContext<Text, LongWritable> context)
         throws IOException, InterruptedException {
       counter = context.getCounter(MyCounter.DIRTY_RECORDS);
     }

     public void map(LongWritable recordNum, Record record,
         MapContext<Text, Text> context) throws IOException,
         InterruptedException {
       if (dirty) {
         counter.increment(1);
       }
     }
   }

   public static void main(String[] args) throws Exception {
    JobConf job = new JobConf();
    ... ...
    RunningJob rJob = JobClient.runJob(job);
    Counters counters = rJob.getCounters();
    long count = counters.findCounter(MyCounter.DIRTY_RECORDS).getValue();
  }
 }
 

See Also:

Counters, CounterGroup, TaskAttemptContext#getCounter(Enum)

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object genericRight)
String	getDisplayName() 获取Counter的显示名称
String	getName() 获取Counter名称
long	getValue() 获取当前Counter计数值
int	hashCode()
void	increment(long incr) 增加Counter计数值
void	readFields(DataInput in) 从DataInput读取Counter信息
void	setValue(long value) 设置Counter计数值
void	write(DataOutput out) 写当前Counter到DataOutput

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Method Detail

getName

public String getName()

获取Counter名称

Returns:

Counter名称

getDisplayName

public String getDisplayName()

获取Counter的显示名称

Returns:

Counter显示名称

getValue

public long getValue()

获取当前Counter计数值

Returns:

当前Counter计数值

setValue

public void setValue(long value)

设置Counter计数值

Parameters:

value - Counter计数值

increment

public void increment(long incr)

增加Counter计数值

Parameters:

incr - Counter计数值的增量

equals

public boolean equals(Object genericRight)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

readFields

public void readFields(DataInput in)
                throws IOException

从DataInput读取Counter信息

Specified by:

readFields in interface Writable

Throws:

IOException

write

public void write(DataOutput out)
           throws IOException

写当前Counter到DataOutput

Specified by:

write in interface Writable

Throws:

IOException