Package org.apache.nutch.crawl

Class CrawlDbMerger

java.lang.Object

org.apache.hadoop.conf.Configured

org.apache.nutch.crawl.CrawlDbMerger

All Implemented Interfaces:

Configurable, Tool

public class CrawlDbMerger
extends Configured
implements Tool

This tool merges several CrawlDb-s into one, optionally filtering URLs through the current URLFilters, to skip prohibited pages.

It's possible to use this tool just for filtering - in that case only one CrawlDb should be specified in arguments.

If more than one CrawlDb contains information about the same URL, only the most recent version is retained, as determined by the value of CrawlDatum.getFetchTime(). However, all metadata information from all versions is accumulated, with newer values taking precedence over older values.

Author:

Andrzej Bialecki

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CrawlDbMerger.Merger

Constructor Summary

Constructors

Constructor	Description
CrawlDbMerger()
CrawlDbMerger(Configuration conf)

Method Summary

Modifier and Type	Method	Description
static Job	createMergeJob(Configuration conf, Path output, boolean normalize, boolean filter)
static void	main(String[] args)	Run the tool.
void	merge(Path output, Path[] dbs, boolean normalize, boolean filter)
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

Constructor Detail

CrawlDbMerger

public CrawlDbMerger()

CrawlDbMerger

public CrawlDbMerger(Configuration conf)

Method Detail

merge

public void merge(Path output,
                  Path[] dbs,
                  boolean normalize,
                  boolean filter)
           throws Exception

Throws:

Exception

createMergeJob

public static Job createMergeJob(Configuration conf,
                                 Path output,
                                 boolean normalize,
                                 boolean filter)
                          throws IOException

Throws:

IOException

main

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

Run the tool.

Parameters:

args - job parameters

Throws:

Exception - if there is an issue executing this job

run

public int run(String[] args)
        throws Exception

Specified by:

run in interface Tool

Throws:

Exception