io.cdap.cdap.api.data.batch

Class RecordScanner<RECORD>

java.lang.Object

io.cdap.cdap.api.data.batch.RecordScanner<RECORD>

Type Parameters:

RECORD - the type of objects that represents a single record

@Beta
public abstract class RecordScanner<RECORD>
extends Object

Defines a reader of a dataset Split.

Constructor Summary

Constructors

Constructor and Description
RecordScanner()

Method Summary

Modifier and Type	Method and Description
abstract void	close() Close the record reader.
abstract RECORD	getCurrentRecord() Get the current record.
float	getProgress() The current progress of the record reader through its data.
abstract void	initialize(Split split) Called once at initialization.
abstract boolean	nextRecord() Read the next record.

Methods inherited from class java.lang.Object

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

Constructor Detail

RecordScanner

public RecordScanner()

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

nextRecord

public abstract boolean nextRecord()
                            throws InterruptedException

Read the next record.

Returns:

true if a record was read.

Throws:

InterruptedException

getCurrentRecord

public abstract RECORD getCurrentRecord()
                                 throws InterruptedException

Get the current record.

Returns:

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

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.