co.cask.cdap.data.stream

Class MultiLiveStreamFileReader

java.lang.Object

co.cask.cdap.data.stream.MultiLiveStreamFileReader

All Implemented Interfaces:

FileReader<StreamEventOffset,Iterable<StreamFileOffset>>, PositionReporter<Iterable<StreamFileOffset>>, Closeable, AutoCloseable

@NotThreadSafe
public final class MultiLiveStreamFileReader
extends Object
implements FileReader<StreamEventOffset,Iterable<StreamFileOffset>>

A FileReader that combines multiple event stream into single event stream.

Constructor Summary

Constructors

Constructor and Description
MultiLiveStreamFileReader(StreamConfig streamConfig, Iterable<? extends StreamFileOffset> offsets)

Method Summary

Methods

Modifier and Type	Method and Description
void	close()
Iterable<StreamFileOffset>	getPosition() Returns the position information.
void	initialize() Initialize the file reader.
int	read(Collection<? super StreamEventOffset> events, int maxEvents, long timeout, TimeUnit unit) Reads as much data as possible until maxEvents.
int	read(Collection<? super StreamEventOffset> events, int maxEvents, long timeout, TimeUnit unit, ReadFilter readFilter) Reads as much data as possible that passes the given filter until maxEvents.

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiLiveStreamFileReader

public MultiLiveStreamFileReader(StreamConfig streamConfig,
                         Iterable<? extends StreamFileOffset> offsets)

Method Detail

initialize

public void initialize()
                throws IOException

Description copied from interface: FileReader

Initialize the file reader.

Specified by:

initialize in interface FileReader<StreamEventOffset,Iterable<StreamFileOffset>>

Throws:

IOException - If initialization failed.

read

public int read(Collection<? super StreamEventOffset> events,
       int maxEvents,
       long timeout,
       TimeUnit unit)
         throws IOException,
                InterruptedException

Description copied from interface: FileReader

Reads as much data as possible until maxEvents.

Specified by:

read in interface FileReader<StreamEventOffset,Iterable<StreamFileOffset>>

Parameters:

events - Collection for storing data read.

maxEvents - Maximum number of events to read.

timeout - Maximum of time to spend on trying to read events

unit - Unit for the timeout.

Returns:

Number of events read, could be 0. If -1 is returned, meaning it reached EOF and all sub-sequence call to this method will also return -1.

Throws:

IOException - If failed to read.

InterruptedException - If the reading is interrupted.

read

public int read(Collection<? super StreamEventOffset> events,
       int maxEvents,
       long timeout,
       TimeUnit unit,
       ReadFilter readFilter)
         throws IOException,
                InterruptedException

Description copied from interface: FileReader

Reads as much data as possible that passes the given filter until maxEvents.

Specified by:

read in interface FileReader<StreamEventOffset,Iterable<StreamFileOffset>>

Parameters:

events - Collection for storing data read.

maxEvents - Maximum number of events to read.

timeout - Maximum of time to spend on trying to read events

unit - Unit for the timeout.

readFilter - Filter to apply during reading

Returns:

Number of events read, could be 0. If -1 is returned, meaning it reached EOF and all sub-sequence call to this method will also return -1.

Throws:

IOException - If failed to read.

InterruptedException - If the reading is interrupted.

getPosition

public Iterable<StreamFileOffset> getPosition()

Description copied from interface: PositionReporter

Returns the position information.

Specified by:

getPosition in interface PositionReporter<Iterable<StreamFileOffset>>

Returns:

An instance of type <P>

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException