Package org.apache.nutch.fetcher

Class FetchItemQueues

java.lang.Object

org.apache.nutch.fetcher.FetchItemQueues

public class FetchItemQueues
extends Object

A collection of queues that keeps track of the total number of items, and provides items eligible for fetching from any queue.

Field Summary

Fields

Modifier and Type	Field	Description
static String	DEFAULT_ID
static String	QUEUE_MODE_DOMAIN
static String	QUEUE_MODE_HOST
static String	QUEUE_MODE_IP

Constructor Summary

Constructors

Constructor	Description
FetchItemQueues(Configuration conf)

Method Summary

Modifier and Type	Method	Description
org.apache.nutch.fetcher.FetchItemQueues.QueuingStatus	addFetchItem(Text url, CrawlDatum datum)
org.apache.nutch.fetcher.FetchItemQueues.QueuingStatus	addFetchItem(FetchItem it)
int	checkExceptionThreshold(String queueid)	Increment the exception counter of a queue in case of an exception e.g.
int	checkExceptionThreshold(String queueid, int maxExceptions, long delay)	Increment the exception counter of a queue in case of an exception e.g.
protected static String	checkQueueMode(String queueMode)	Check whether queue mode is valid, fall-back to default mode if not.
int	checkTimelimit()
void	dump()
int	emptyQueues()
void	finishFetchItem(FetchItem it)
void	finishFetchItem(FetchItem it, boolean asap)
FetchItem	getFetchItem()
FetchItemQueue	getFetchItemQueue(String id)
int	getQueueCount()
int	getQueueCountMaxExceptions()
int	getTotalSize()
boolean	redirectIsQueuedRecently(Text redirUrl)
void	setTimeoutReached()	Signal that the hard timeout is reached because new fetches / requests where made during half of the MapReduce task timeout (mapreduce.task.timeout, default value: 10 minutes).
boolean	timelimitExceeded()

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_ID

public static final String DEFAULT_ID

See Also:

Constant Field Values

QUEUE_MODE_HOST

public static final String QUEUE_MODE_HOST

See Also:

Constant Field Values

QUEUE_MODE_DOMAIN

public static final String QUEUE_MODE_DOMAIN

See Also:

Constant Field Values

QUEUE_MODE_IP

public static final String QUEUE_MODE_IP

See Also:

Constant Field Values

Constructor Detail

FetchItemQueues

public FetchItemQueues(Configuration conf)

Method Detail

checkQueueMode

protected static String checkQueueMode(String queueMode)

Check whether queue mode is valid, fall-back to default mode if not.

Parameters:

queueMode - queue mode to check

Returns:

valid queue mode or default

getTotalSize

public int getTotalSize()

getQueueCount

public int getQueueCount()

getQueueCountMaxExceptions

public int getQueueCountMaxExceptions()

addFetchItem

public org.apache.nutch.fetcher.FetchItemQueues.QueuingStatus addFetchItem(Text url,
                                                                           CrawlDatum datum)

addFetchItem

public org.apache.nutch.fetcher.FetchItemQueues.QueuingStatus addFetchItem(FetchItem it)

finishFetchItem

public void finishFetchItem(FetchItem it)

finishFetchItem

public void finishFetchItem(FetchItem it,
                            boolean asap)

getFetchItemQueue

public FetchItemQueue getFetchItemQueue(String id)

getFetchItem

public FetchItem getFetchItem()

timelimitExceeded

public boolean timelimitExceeded()

Returns:

true if the fetcher timelimit is defined and has been exceeded (fetcher.timelimit.mins minutes after fetching started)

checkTimelimit

public int checkTimelimit()

setTimeoutReached

public void setTimeoutReached()

Signal that the hard timeout is reached because new fetches / requests where made during half of the MapReduce task timeout (mapreduce.task.timeout, default value: 10 minutes). In order to avoid that the task timeout is hit and the fetcher job is failed, we stop the fetching now. See also the property fetcher.threads.timeout.divisor.

emptyQueues

public int emptyQueues()

checkExceptionThreshold

public int checkExceptionThreshold(String queueid,
                                   int maxExceptions,
                                   long delay)

Increment the exception counter of a queue in case of an exception e.g. timeout; when higher than a given threshold simply empty the queue. The next fetch is delayed if specified by the param delay or configured by the property fetcher.exceptions.per.queue.delay.

Parameters:

queueid - a queue identifier to locate and check

maxExceptions - custom-defined number of max. exceptions - if negative the value of the property fetcher.max.exceptions.per.queue is used.

delay - a custom-defined time span in milliseconds to delay the next fetch in addition to the delay defined for the given queue. If a negative value is passed the delay is chosen by fetcher.exceptions.per.queue.delay

Returns:

number of purged items

checkExceptionThreshold

public int checkExceptionThreshold(String queueid)

Increment the exception counter of a queue in case of an exception e.g. timeout; when higher than a given threshold simply empty the queue.

Parameters:

queueid - queue identifier to locate and check

Returns:

number of purged items

See Also:

checkExceptionThreshold(String, int, long)

redirectIsQueuedRecently

public boolean redirectIsQueuedRecently(Text redirUrl)

Parameters:

redirUrl - redirect target

Returns:

true if redirects are deduplicated and redirUrl has been queued recently

dump

public void dump()