org.apache.nutch.tools
Class CrawlDBScanner

java.lang.Object
  org.apache.hadoop.conf.Configured
      org.apache.nutch.tools.CrawlDBScanner

All Implemented Interfaces:

Closeable, Configurable, JobConfigurable, Mapper<Text,CrawlDatum,Text,CrawlDatum>, Reducer<Text,CrawlDatum,Text,CrawlDatum>, Tool

public class CrawlDBScanner
extends Configured
implements Tool, Mapper<Text,CrawlDatum,Text,CrawlDatum>, Reducer<Text,CrawlDatum,Text,CrawlDatum>

Dumps all the entries matching a regular expression on their URL. Generates a text representation of the CrawlDatum-s or binary objects which can then be used as a new CrawlDB. The dump mechanism of the crawldb reader is not very useful on large crawldbs as the ouput can be extremely large and the -url function can't help if we don't know what url we want to have a look at.

Author:

: Julien Nioche

Field Summary

static org.slf4j.Logger

LOG

Constructor Summary

CrawlDBScanner()

CrawlDBScanner(Configuration conf)

Method Summary

void	close()
void	configure(JobConf job)
static void	main(String[] args)
void	map(Text url, CrawlDatum crawlDatum, OutputCollector<Text,CrawlDatum> output, Reporter reporter)
void	reduce(Text key, Iterator<CrawlDatum> values, OutputCollector<Text,CrawlDatum> output, Reporter reporter)
int	run(String[] args)

Methods inherited from class org.apache.hadoop.conf.Configured

getConf, setConf

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.conf.Configurable

getConf, setConf

Field Detail

LOG

public static final org.slf4j.Logger LOG

Constructor Detail

CrawlDBScanner

public CrawlDBScanner()

CrawlDBScanner

public CrawlDBScanner(Configuration conf)

Method Detail

close

public void close()

Specified by:

close in interface Closeable

configure

public void configure(JobConf job)

Specified by:

configure in interface JobConfigurable

map

public void map(Text url,
                CrawlDatum crawlDatum,
                OutputCollector<Text,CrawlDatum> output,
                Reporter reporter)
         throws IOException

Specified by:

map in interface Mapper<Text,CrawlDatum,Text,CrawlDatum>

Throws:

IOException

reduce

public void reduce(Text key,
                   Iterator<CrawlDatum> values,
                   OutputCollector<Text,CrawlDatum> output,
                   Reporter reporter)
            throws IOException

Specified by:

reduce in interface Reducer<Text,CrawlDatum,Text,CrawlDatum>

Throws:

IOException

main

public static void main(String[] args)
                 throws Exception

Throws:

Exception

run

public int run(String[] args)
        throws Exception

Specified by:

run in interface Tool

Throws:

Exception