org.apache.flume.source

Class AbstractPollableSource

java.lang.Object

org.apache.flume.source.BasicSourceSemantics

org.apache.flume.source.AbstractPollableSource

All Implemented Interfaces:

Configurable, LifecycleAware, NamedComponent, PollableSource, Source

Direct Known Subclasses:

JMSSource, KafkaSource, SequenceGeneratorSource, StressSource

@InterfaceAudience.Public
 @InterfaceStability.Evolving
public abstract class AbstractPollableSource
extends BasicSourceSemantics
implements PollableSource

Base class which ensures sub-classes will inherit all the properties of BasicSourceSemantics in addition to:

1. Ensuring when configure/start throw an exception process will not be called
2. Ensure that process will not be called unless configure and start have successfully been called

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flume.PollableSource

PollableSource.Status

Constructor Summary

Constructors

Constructor and Description
AbstractPollableSource()

Method Summary

Modifier and Type	Method and Description
void	configure(Context context) Request the implementing class to (re)configure itself.
protected abstract PollableSource.Status	doProcess()
long	getBackOffSleepIncrement()
long	getMaxBackOffSleepInterval()
PollableSource.Status	process() Attempt to pull an item from the source, sending it to the channel.

Methods inherited from class org.apache.flume.source.BasicSourceSemantics

doConfigure, doStart, doStop, getChannelProcessor, getLifecycleState, getName, getStartException, isStarted, setChannelProcessor, setLifecycleState, setName, start, stop, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.flume.Source

getChannelProcessor, setChannelProcessor

Methods inherited from interface org.apache.flume.lifecycle.LifecycleAware

getLifecycleState, start, stop

Methods inherited from interface org.apache.flume.NamedComponent

getName, setName

Constructor Detail

AbstractPollableSource

public AbstractPollableSource()

Method Detail

process

public PollableSource.Status process()
                              throws EventDeliveryException

Description copied from interface: PollableSource

Attempt to pull an item from the source, sending it to the channel.

When driven by an EventDrivenSourceRunner process is guaranteed to be called only by a single thread at a time, with no concurrency. Any other mechanism driving a pollable source must follow the same semantics.

Specified by:

process in interface PollableSource

Returns:

READY if one or more events were created from the source. BACKOFF if no events could be created from the source.

Throws:

EventDeliveryException - If there was a failure in delivering to the attached channel, or if a failure occurred in acquiring data from the source.

configure

public void configure(Context context)

Description copied from interface: Configurable

Request the implementing class to (re)configure itself.

When configuration parameters are changed, they must be reflected by the component asap.

There are no thread safety guarantees on when configure might be called.

Specified by:

configure in interface Configurable

Overrides:

configure in class BasicSourceSemantics

getBackOffSleepIncrement

public long getBackOffSleepIncrement()

Specified by:

getBackOffSleepIncrement in interface PollableSource

getMaxBackOffSleepInterval

public long getMaxBackOffSleepInterval()

Specified by:

getMaxBackOffSleepInterval in interface PollableSource

doProcess

protected abstract PollableSource.Status doProcess()
                                            throws EventDeliveryException

Throws:

EventDeliveryException