io.cdap.cdap.api.data.batch

Class SplitReader<KEY,VALUE>

java.lang.Object

io.cdap.cdap.api.data.batch.SplitReader<KEY,VALUE>

Type Parameters:

KEY - The key type.

VALUE - The value type.

Direct Known Subclasses:

KeyValueTable.KeyValueScanner, SplitReaderAdapter, SplitReaderBase

public abstract class SplitReader<KEY,VALUE>
extends Object

Defines a reader of a dataset Split.

Constructor Summary

Constructors

Constructor and Description
SplitReader()

Method Summary

Modifier and Type	Method and Description
abstract void	close() Close the record reader.
abstract KEY	getCurrentKey() Get the current key.
abstract VALUE	getCurrentValue() Get the current value.
float	getProgress() The current progress of the record reader through its data.
abstract void	initialize(Split split) Called once at initialization.
abstract boolean	nextKeyValue() Read the next key, value pair.

Methods inherited from class java.lang.Object

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

Constructor Detail

SplitReader

public SplitReader()

Method Detail

initialize

public abstract void initialize(Split split)
                         throws InterruptedException

Called once at initialization.

Parameters:

split - The split that defines the range of records to read.

Throws:

InterruptedException

nextKeyValue

public abstract boolean nextKeyValue()
                              throws InterruptedException

Read the next key, value pair.

Returns:

true if a key/value pair was read.

Throws:

InterruptedException

getCurrentKey

public abstract KEY getCurrentKey()
                           throws InterruptedException

Get the current key.

Returns:

The current key, or null if there is no current key.

Throws:

InterruptedException

getCurrentValue

public abstract VALUE getCurrentValue()
                               throws InterruptedException

Get the current value.

Returns:

The current value of the object that was read.

Throws:

InterruptedException

getProgress

public float getProgress()
                  throws InterruptedException

The current progress of the record reader through its data. By default progress is not reported in the middle of split reading.

Returns:

A number between 0.0 and 1.0 that is the fraction of the data that has been read.

Throws:

InterruptedException

close

public abstract void close()

Close the record reader.