com.asakusafw.runtime.stage.collector

Class SlotDistributor<T extends org.apache.hadoop.io.Writable>

java.lang.Object

org.apache.hadoop.mapreduce.Mapper<KEYIN,VALUEIN,KEYOUT,VALUEOUT>

com.asakusafw.runtime.flow.MapperWithRuntimeResource<Object,T,SortableSlot,WritableSlot>

com.asakusafw.runtime.stage.collector.SlotDistributor<T>

Type Parameters:

T - the data type

public abstract class SlotDistributor<T extends org.apache.hadoop.io.Writable>
extends MapperWithRuntimeResource<Object,T,SortableSlot,WritableSlot>

The skeletal implementation of Hadoop Mapper for distributing values into SlotSorter.

Since:

0.1.0

Version:

0.5.1

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.mapreduce.Mapper

org.apache.hadoop.mapreduce.Mapper.Context

Field Summary

Fields

Modifier and Type	Field and Description
static String	NAME_SET_SLOT_SPEC The method name of setSlotSpec(Writable, SortableSlot).

Constructor Summary

Constructors

Constructor and Description
SlotDistributor()

Method Summary

Modifier and Type	Method and Description
protected void	map(Object key, T value, org.apache.hadoop.mapreduce.Mapper.Context context)
protected abstract void	setSlotSpec(T value, SortableSlot slot) Sets sorting information into the target slot.

Methods inherited from class com.asakusafw.runtime.flow.MapperWithRuntimeResource

run, runInternal

Methods inherited from class org.apache.hadoop.mapreduce.Mapper

cleanup, setup

Methods inherited from class java.lang.Object

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

Field Detail

NAME_SET_SLOT_SPEC

public static final String NAME_SET_SLOT_SPEC

The method name of setSlotSpec(Writable, SortableSlot).

See Also:

Constant Field Values

Constructor Detail

SlotDistributor

public SlotDistributor()

Method Detail

setSlotSpec

protected abstract void setSlotSpec(T value,
                                    SortableSlot slot)
                             throws IOException

Sets sorting information into the target slot. Sub-class must set its slot number before write any properties as like following:

slot.begin(MY_SLOT_NUMBER);
slot.addWritable(value.getPrimaryKey());
slot.addWritable(value.getSecondaryKey());
...

Parameters:

value - the target value

slot - the target slot

Throws:

IOException - if failed to write

map

protected void map(Object key,
                   T value,
                   org.apache.hadoop.mapreduce.Mapper.Context context)
            throws IOException,
                   InterruptedException

Overrides:

map in class org.apache.hadoop.mapreduce.Mapper<Object,T extends org.apache.hadoop.io.Writable,SortableSlot,WritableSlot>

Throws:

IOException

InterruptedException