com.asakusafw.runtime.flow

Class ResultOutput<T>

java.lang.Object

com.asakusafw.runtime.flow.ResultOutput<T>

Type Parameters:

T - the data model type

All Implemented Interfaces:

Result<T>

public class ResultOutput<T>
extends Object
implements Result<T>

An implementation of Result which put data model objects into the final output.

Since:

0.1.0

Version:

0.5.0

Nested Class Summary

Nested classes/interfaces inherited from interface com.asakusafw.runtime.core.Result

Result.OutputException

Constructor Summary

Constructors

Constructor and Description
ResultOutput(org.apache.hadoop.mapreduce.TaskAttemptContext context, org.apache.hadoop.mapreduce.RecordWriter writer) Creates a new instance.
ResultOutput(org.apache.hadoop.mapreduce.TaskAttemptContext context, org.apache.hadoop.mapreduce.RecordWriter writer, List<org.apache.hadoop.mapreduce.Counter> counters) Creates a new instance.

Method Summary

Modifier and Type	Method and Description
void	add(T result) Adds an object into this result.
void	close() Finalizes and closes this output.
protected Object	getKey(T result) Returns a key for the value.
String	toString()
static <K,V> void	write(org.apache.hadoop.mapreduce.TaskInputOutputContext<?,?,? super K,? super V> context, K key, V value) Writes a key and value into current context.

Methods inherited from class java.lang.Object

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

Constructor Detail

ResultOutput

public ResultOutput(org.apache.hadoop.mapreduce.TaskAttemptContext context,
                    org.apache.hadoop.mapreduce.RecordWriter writer)
             throws IOException,
                    InterruptedException

Creates a new instance.

Parameters:

context - the current context

writer - the record writer for writing data model objects

Throws:

IOException - if failed to initialize the output

InterruptedException - if interrupted while initializing the output

IllegalArgumentException - if some parameters are null

ResultOutput

public ResultOutput(org.apache.hadoop.mapreduce.TaskAttemptContext context,
                    org.apache.hadoop.mapreduce.RecordWriter writer,
                    List<org.apache.hadoop.mapreduce.Counter> counters)
             throws IOException,
                    InterruptedException

Creates a new instance.

Parameters:

context - current context

writer - target writer

counters - record counters

Throws:

IOException - if initialization failed by I/O exception

InterruptedException - if interrupted

IllegalArgumentException - if some parameters were null

Since:

0.2.5

Method Detail

write

public static <K,V> void write(org.apache.hadoop.mapreduce.TaskInputOutputContext<?,?,? super K,? super V> context,
                               K key,
                               V value)

Writes a key and value into current context.

Type Parameters:

K - type of key object

V - type of value object

Parameters:

context - current context

key - the key object (nullable)

value - the value object (nullable)

Throws:

Result.OutputException - if failed to write the objects

Since:

0.5.0

add

public void add(T result)

Description copied from interface: Result

Adds an object into this result. Generally, this object accepts two or more objects per an operation. This method will modify properties in the added object, so that clients should create a copy the object if the object will be continuously used.

Specified by:

add in interface Result<T>

Parameters:

result - the target object

getKey

protected Object getKey(T result)

Returns a key for the value.

Parameters:

result - target value

Returns:

a corresponded key

close

public void close()
           throws IOException,
                  InterruptedException

Finalizes and closes this output.

Throws:

IOException - if failed to finalize the output

InterruptedException - if interrupted while finalizing the output

toString

public String toString()

Overrides:

toString in class Object