org.archive.crawler.framework
Class ToePool

java.lang.Object
  java.lang.ThreadGroup
      org.archive.crawler.framework.ToePool

All Implemented Interfaces:

java.lang.Thread.UncaughtExceptionHandler, Reporter

public class ToePool
extends java.lang.ThreadGroup
implements Reporter

A collection of ToeThreads. The class manages the ToeThreads currently running. Including increasing and decreasing their number, keeping track of their state and it can be used to kill hung threads.

Author:

Gordon Mohr, Kristinn Sigurdsson

See Also:

ToeThread

Field Summary

static java.lang.String	COMPACT_REPORT
protected CrawlController	controller
static int	DEFAULT_TOE_PRIORITY run worker thread slightly lower than usual
protected int	nextSerialNumber
protected static java.lang.String[]	REPORTS
static java.lang.String	STANDARD_REPORT
protected int	targetSize

Constructor Summary

ToePool(CrawlController c)
Constructor.

Method Summary

void	cleanup()
protected void	compactReportTo(java.io.PrintWriter writer)
int	getActiveToeCount()
CrawlController	getController()
java.lang.String[]	getReports() Get an array of report names offered by this Reporter.
int	getToeCount()
void	killThread(int threadNumber, boolean replace) Kills specified thread.
void	reportTo(java.io.PrintWriter writer) Make a default report to the passed-in Writer.
void	reportTo(java.lang.String name, java.io.PrintWriter writer) Make a report of the given name to the passed-in Writer, If null, give the default report.
void	setSize(int newsize) Change the number of ToeThreads.
java.lang.String	singleLineLegend() Return a legend for the single-line summary report as a String.
java.lang.String	singleLineReport() Return a short single-line summary report as a String.
void	singleLineReportTo(java.io.PrintWriter w) Make a single-line summary report to the passed-in writer
protected void	standardReportTo(java.io.PrintWriter writer)

Methods inherited from class java.lang.ThreadGroup

activeCount, activeGroupCount, allowThreadSuspension, checkAccess, destroy, enumerate, enumerate, enumerate, enumerate, getMaxPriority, getName, getParent, interrupt, isDaemon, isDestroyed, list, parentOf, resume, setDaemon, setMaxPriority, stop, suspend, toString, uncaughtException

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_TOE_PRIORITY

public static int DEFAULT_TOE_PRIORITY

run worker thread slightly lower than usual

controller

protected CrawlController controller

nextSerialNumber

protected int nextSerialNumber

targetSize

protected int targetSize

STANDARD_REPORT

public static java.lang.String STANDARD_REPORT

COMPACT_REPORT

public static java.lang.String COMPACT_REPORT

REPORTS

protected static java.lang.String[] REPORTS

Constructor Detail

ToePool

public ToePool(CrawlController c)

Constructor. Creates a pool of ToeThreads.

Parameters:

c - A reference to the CrawlController for the current crawl.

Method Detail

cleanup

public void cleanup()

getActiveToeCount

public int getActiveToeCount()

Returns:

The number of ToeThreads that are not available (Approximation).

getToeCount

public int getToeCount()

Returns:

The number of ToeThreads. This may include killed ToeThreads that were not replaced.

setSize

public void setSize(int newsize)

Change the number of ToeThreads.

Parameters:

newsize - The new number of ToeThreads.

killThread

public void killThread(int threadNumber,
                       boolean replace)

Kills specified thread. Killed thread can be optionally replaced with a new thread.

WARNING: This operation should be used with great care. It may destabilize the crawler.

Parameters:

threadNumber - Thread to kill

replace - If true then a new thread will be created to take the killed threads place. Otherwise the total number of threads will decrease by one.

getController

public CrawlController getController()

Returns:

Instance of CrawlController.

getReports

public java.lang.String[] getReports()

Description copied from interface: Reporter

Get an array of report names offered by this Reporter. A name in brackets indicates a free-form String, in accordance with the informal description inside the brackets, may yield a useful report.

Specified by:

getReports in interface Reporter

Returns:

String array of report names, empty if there is only one report type

reportTo

public void reportTo(java.lang.String name,
                     java.io.PrintWriter writer)

Description copied from interface: Reporter

Make a report of the given name to the passed-in Writer, If null, give the default report.

Specified by:

reportTo in interface Reporter

writer - to receive report

standardReportTo

protected void standardReportTo(java.io.PrintWriter writer)

compactReportTo

protected void compactReportTo(java.io.PrintWriter writer)

singleLineReportTo

public void singleLineReportTo(java.io.PrintWriter w)

Description copied from interface: Reporter

Make a single-line summary report to the passed-in writer

Specified by:

singleLineReportTo in interface Reporter

Parameters:

w - to receive report

singleLineLegend

public java.lang.String singleLineLegend()

Description copied from interface: Reporter

Return a legend for the single-line summary report as a String.

Specified by:

singleLineLegend in interface Reporter

Returns:

String single-line summary legend

singleLineReport

public java.lang.String singleLineReport()

Description copied from interface: Reporter

Return a short single-line summary report as a String.

Specified by:

singleLineReport in interface Reporter

Returns:

String single-line summary report

reportTo

public void reportTo(java.io.PrintWriter writer)

Description copied from interface: Reporter

Make a default report to the passed-in Writer. Should be equivalent to reportTo(null, writer)

Specified by:

reportTo in interface Reporter

Parameters:

writer - to receive report