org.apache.nifi.processor.util.listen

Class AbstractListenEventProcessor<E extends Event>

java.lang.Object

org.apache.nifi.components.AbstractConfigurableComponent

org.apache.nifi.processor.AbstractSessionFactoryProcessor

org.apache.nifi.processor.AbstractProcessor

org.apache.nifi.processor.util.listen.AbstractListenEventProcessor<E>

Type Parameters:

E - the type of events being produced

All Implemented Interfaces:

ConfigurableComponent, Processor

Direct Known Subclasses:

AbstractListenEventBatchingProcessor

public abstract class AbstractListenEventProcessor<E extends Event>
extends AbstractProcessor

An abstract processor to extend from when listening for events over a channel. This processor will start a ChannelDispatcher, and optionally a ChannelResponseDispatcher, in a background thread which will end up placing events on a queue to polled by the onTrigger method. Sub-classes are responsible for providing the dispatcher implementations.

Field Summary

Fields

Modifier and Type	Field and Description
protected Charset	charset
static PropertyDescriptor	CHARSET
protected List<PropertyDescriptor>	descriptors
protected ChannelDispatcher	dispatcher
protected BlockingQueue<E>	errorEvents
protected BlockingQueue<E>	events
static PropertyDescriptor	MAX_CONNECTIONS
static PropertyDescriptor	MAX_MESSAGE_QUEUE_SIZE
static PropertyDescriptor	MAX_SOCKET_BUFFER_SIZE
static int	POLL_TIMEOUT_MS
protected int	port
static PropertyDescriptor	PORT
static PropertyDescriptor	RECV_BUFFER_SIZE
static Relationship	REL_SUCCESS
protected Set<Relationship>	relationships

Constructor Summary

Constructors

Constructor and Description
AbstractListenEventProcessor()

Method Summary

Modifier and Type	Method and Description
protected BlockingQueue<ByteBuffer>	createBufferPool(int poolSize, int bufferSize) Creates a pool of ByteBuffers with the given size.
protected abstract ChannelDispatcher	createDispatcher(ProcessContext context, BlockingQueue<E> events)
protected List<PropertyDescriptor>	getAdditionalProperties() Override to provide additional properties for the processor.
protected List<Relationship>	getAdditionalRelationships() Override to provide additional relationships for the processor.
int	getDispatcherPort()
int	getErrorQueueSize()
protected long	getLongPollTimeout()
protected E	getMessage(boolean longPoll, boolean pollErrorQueue, ProcessSession session) If pollErrorQueue is true, the error queue will be checked first and event will be returned from the error queue if available.
int	getQueueSize()
Set<Relationship>	getRelationships()
List<PropertyDescriptor>	getSupportedPropertyDescriptors()
protected void	init(ProcessorInitializationContext context)
void	onScheduled(ProcessContext context)
void	onUnscheduled()

Methods inherited from class org.apache.nifi.processor.AbstractProcessor

onTrigger, onTrigger

Methods inherited from class org.apache.nifi.processor.AbstractSessionFactoryProcessor

getControllerServiceLookup, getIdentifier, getLogger, getNodeTypeProvider, initialize, isConfigurationRestored, isScheduled, toString, updateConfiguredRestoredTrue, updateScheduledFalse, updateScheduledTrue

Methods inherited from class org.apache.nifi.components.AbstractConfigurableComponent

customValidate, equals, getPropertyDescriptor, getPropertyDescriptors, getSupportedDynamicPropertyDescriptor, hashCode, onPropertyModified, validate

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.nifi.components.ConfigurableComponent

getPropertyDescriptor, getPropertyDescriptors, onPropertyModified, validate

Field Detail

PORT

public static final PropertyDescriptor PORT

CHARSET

public static final PropertyDescriptor CHARSET

RECV_BUFFER_SIZE

public static final PropertyDescriptor RECV_BUFFER_SIZE

MAX_SOCKET_BUFFER_SIZE

public static final PropertyDescriptor MAX_SOCKET_BUFFER_SIZE

MAX_MESSAGE_QUEUE_SIZE

public static final PropertyDescriptor MAX_MESSAGE_QUEUE_SIZE

MAX_CONNECTIONS

public static final PropertyDescriptor MAX_CONNECTIONS

REL_SUCCESS

public static final Relationship REL_SUCCESS

POLL_TIMEOUT_MS

public static final int POLL_TIMEOUT_MS

See Also:

Constant Field Values

relationships

protected Set<Relationship> relationships

descriptors

protected List<PropertyDescriptor> descriptors

port

protected volatile int port

charset

protected volatile Charset charset

dispatcher

protected volatile ChannelDispatcher dispatcher

events

protected volatile BlockingQueue<E extends Event> events

errorEvents

protected volatile BlockingQueue<E extends Event> errorEvents

Constructor Detail

AbstractListenEventProcessor

public AbstractListenEventProcessor()

Method Detail

init

protected void init(ProcessorInitializationContext context)

Overrides:

init in class AbstractSessionFactoryProcessor

getAdditionalRelationships

protected List<Relationship> getAdditionalRelationships()

Override to provide additional relationships for the processor.

Returns:

a list of relationships

getAdditionalProperties

protected List<PropertyDescriptor> getAdditionalProperties()

Override to provide additional properties for the processor.

Returns:

a list of properties

getRelationships

public final Set<Relationship> getRelationships()

Specified by:

getRelationships in interface Processor

Overrides:

getRelationships in class AbstractSessionFactoryProcessor

getSupportedPropertyDescriptors

public final List<PropertyDescriptor> getSupportedPropertyDescriptors()

Overrides:

getSupportedPropertyDescriptors in class AbstractConfigurableComponent

onScheduled

@OnScheduled
public void onScheduled(ProcessContext context)
                              throws IOException

Throws:

IOException

createDispatcher

protected abstract ChannelDispatcher createDispatcher(ProcessContext context,
                                                      BlockingQueue<E> events)
                                               throws IOException

Parameters:

context - the ProcessContext to retrieve property values from

Returns:

a ChannelDispatcher to handle incoming connections

Throws:

IOException - if unable to listen on the requested port

getDispatcherPort

public final int getDispatcherPort()

getErrorQueueSize

public int getErrorQueueSize()

getQueueSize

public int getQueueSize()

onUnscheduled

@OnUnscheduled
public void onUnscheduled()

createBufferPool

protected BlockingQueue<ByteBuffer> createBufferPool(int poolSize,
                                                     int bufferSize)

Creates a pool of ByteBuffers with the given size.

Parameters:

poolSize - the number of buffers to initialize the pool with

bufferSize - the size of each buffer

Returns:

a blocking queue with size equal to poolSize and each buffer equal to bufferSize

getMessage

protected E getMessage(boolean longPoll,
                       boolean pollErrorQueue,
                       ProcessSession session)

If pollErrorQueue is true, the error queue will be checked first and event will be returned from the error queue if available. If pollErrorQueue is false, or no data is in the error queue, the regular queue is polled. If longPoll is true, the regular queue will be polled with a short timeout, otherwise it will poll with no timeout which will return immediately.

Parameters:

longPoll - whether or not to poll the main queue with a small timeout

pollErrorQueue - whether or not to poll the error queue first

Returns:

an event from one of the queues, or null if none are available

getLongPollTimeout

protected long getLongPollTimeout()