# All Classes

- All Classes Interface Summary Class Summary Enum Summary Exception Summary
  Class | Description
  --- | ---
  AbstractChecker | Scaffolding class for the various Checker implementations.
  AbstractCommonCrawlFormat | Abstract class that implements { @see org.apache.nutch.tools.CommonCrawlFormat } interface.
  AbstractFetchSchedule | This class provides common methods for implementations of `FetchSchedule`.
  AbstractResource |
  AbstractScoringFilter |
  AdaptiveFetchSchedule | This class implements an adaptive re-fetch algorithm.
  AdminResource |
  AjaxURLNormalizer | URLNormalizer capable of dealing with AJAX URL's.
  AnchorIndexingFilter | Indexing filter that offers an option to either index all inbound anchor text for a document or deduplicate anchors.
  ArbitraryIndexingFilter | Adds arbitrary searchable fields to a document from the class and method the user identifies in the config.
  ArcInputFormat | A input format the reads arc files.
  ArcRecordReader | The `ArchRecordReader` class provides a record reader which reads records from arc files.
  ArcSegmentCreator | The `ArcSegmentCreator` is a replacement for fetcher that will take arc files as input and produce a nutch segment as output.
  ArcSegmentCreator.ArcSegmentCreatorMapper |
  AutomatonURLFilter | RegexURLFilterBase implementation based on the dk.brics.automaton Finite-State Automata for JavaTM.
  BasicIndexingFilter | Adds basic searchable fields to a document.
  BasicURLNormalizer | Converts URLs to a normal form: remove dot segments in path: `/./` or `/../` remove default ports, e.g.
  BlockedException |
  CaseInsensitiveMetadata | A decorator to Metadata that adds for case-insensitive lookup of keys.
  CCIndexingFilter | Adds basic searchable fields to a document.
  CCParseFilter | Adds metadata identifying the Creative Commons license used, if any.
  CCParseFilter.Walker | Walks DOM tree, looking for RDF in comments and licenses in anchors.
  CIDR | Parse a CIDR block notation and test whether an IP address is contained in the subnet range defined by the CIDR.
  CircularDependencyException | `CircularDependencyException` will be thrown if a circular dependency is detected.
  Classify |
  CleaningJob | The class scans CrawlDB looking for entries with status DB_GONE (404) or DB_DUPLICATE and sends delete requests to indexers for those documents.
  CleaningJob.DBFilter |
  CleaningJob.DeleterReducer |
  Client | Client.java encapsulates functionalities necessary for nutch to get dir list and retrieve file from an FTP server.
  CloudSearchConstants |
  CloudSearchIndexWriter | Writes documents to CloudSearch.
  CloudSearchUtils |
  CollectionManager |
  CommandRunner |
  CommonCrawlConfig |
  CommonCrawlDataDumper | The Common Crawl Data Dumper tool enables one to reverse generate the raw content from Nutch segment data directories into a common crawling data format, consumed by many applications.
  CommonCrawlFormat | Interface for all CommonCrawl formatter.
  CommonCrawlFormatFactory | Factory class that creates new `CommonCrawlFormat` objects (a.k.a.
  CommonCrawlFormatJackson | This class provides methods to map crawled data on JSON using Jackson Streaming APIs.
  CommonCrawlFormatJettinson | This class provides methods to map crawled data on JSON using Jettinson APIs.
  CommonCrawlFormatSimple | This class provides methods to map crawled data on JSON using a StringBuilder object.
  CommonCrawlFormatWARC |
  ConfigResource |
  ConfManager |
  ConfManagerImpl |
  Content |
  ContentAsTextInputFormat | An input format that takes Nutch Content objects and converts them to text while converting newline endings to spaces.
  CosineSimilarity |
  CrawlCompletionStats | Extracts some simple crawl completion stats from the crawldb Stats will be sorted by host/domain and will be of the form: 1 www.spitzer.caltech.edu FETCHED 50 www.spitzer.caltech.edu UNFETCHED
  CrawlCompletionStats.CrawlCompletionStatsCombiner |
  CrawlDatum |
  CrawlDatum.Comparator | A Comparator optimized for CrawlDatum.
  CrawlDatumProcessor | These are instantiated once for each host.
  CrawlDb | This class takes the output of the fetcher and updates the crawldb accordingly.
  CrawlDbFilter | This class provides a way to separate the URL normalization and filtering steps from the rest of CrawlDb manipulation code.
  CrawlDbMerger | This tool merges several CrawlDb-s into one, optionally filtering URLs through the current URLFilters, to skip prohibited pages.
  CrawlDbMerger.Merger |
  CrawlDbReader | Read utility for the CrawlDB.
  CrawlDbReader.CrawlDatumCsvOutputFormat |
  CrawlDbReader.CrawlDatumCsvOutputFormat.LineRecordWriter |
  CrawlDbReader.CrawlDatumJsonOutputFormat |
  CrawlDbReader.CrawlDatumJsonOutputFormat.LineRecordWriter |
  CrawlDbReader.CrawlDatumJsonOutputFormat.WritableSerializer |
  CrawlDbReader.CrawlDbDumpMapper |
  CrawlDbReader.CrawlDbStatMapper |
  CrawlDbReader.CrawlDbStatReducer |
  CrawlDbReader.CrawlDbTopNMapper |
  CrawlDbReader.CrawlDbTopNReducer |
  CrawlDbReader.JsonIndenter |
  CrawlDbReducer | Merge new page entries with existing entries.
  CreativeCommons | A collection of Creative Commons properties names.
  CSVConstants |
  CSVIndexWriter | Write Nutch documents to a CSV file (comma separated values), i.e., dump index as CSV or tab-separated plain text table.
  DbQuery |
  DbResource |
  DebugParseFilter | Adds serialized DOM to parse data, useful for debugging, to understand how the parser implementation interprets a document (not only HTML).
  DeduplicationJob | Generic deduplicator which groups fetched URLs with the same digest and marks all of them as duplicate except the one with the highest score (based on the score in the crawldb, which is not necessarily the same as the score indexed).
  DeduplicationJob.DBFilter |
  DeduplicationJob.DedupReducer<K extends Writable> |
  DeduplicationJob.StatusUpdateReducer | Combine multiple new entries for a url.
  DefalultMultiInteractionHandler | This is a placeholder/example of a technique or use case where we do multiple interaction with the web driver and need data from each such interaction in the end.
  DefaultClickAllAjaxLinksHandler | This handler clicks all the `` tags because it considers them as not usual links but ajax links/interactions.
  DefaultFetchSchedule | This class implements the default re-fetch schedule.
  DefaultHandler |
  DeflateUtils | A collection of utility methods for working on deflated data.
  DepthScoringFilter | This scoring filter limits the number of hops from the initial seed urls.
  DmozParser | Utility that converts DMOZ RDF into a flat file of URLs to be injected.
  DocVector |
  DomainDenylistURLFilter | Filters URLs based on a file containing domain suffixes, domain names, and hostnames.
  DomainStatistics | Extracts some very basic statistics about domains from the crawldb
  DomainStatistics.DomainStatisticsCombiner |
  DomainStatistics.MyCounter |
  DomainURLFilter | Filters URLs based on a file containing domain suffixes, domain names, and hostnames.
  DOMBuilder | This class takes SAX events (in addition to some extra events that SAX doesn't handle yet) and adds the result to a document or document fragment.
  DOMContentUtils | A collection of methods for extracting content from DOM trees.
  DOMContentUtils | A collection of methods for extracting content from DOM trees.
  DOMContentUtils.LinkParams |
  DomUtil |
  DublinCore | A collection of Dublin Core metadata names.
  DummyConstants |
  DummyIndexWriter | DummyIndexWriter.
  DummySSLProtocolSocketFactory |
  DummyX509TrustManager |
  DummyX509TrustManager |
  DummyX509TrustManager |
  DummyX509TrustManager |
  DummyX509TrustManager |
  DumpFileUtil |
  ElasticConstants |
  ElasticIndexWriter | Sends NutchDocuments to a configured Elasticsearch index.
  EncodingDetector | A simple class for detecting character encodings.
  Exchange |
  ExchangeConfig |
  Exchanges |
  ExemptionUrlFilter | This implementation of `URLExemptionFilter` uses regex configuration to check if URL is eligible for exemption from the `db.ignore.external.links` configuration property.
  Extension | An `Extension` is a kind of listener descriptor that will be installed on a concrete `ExtensionPoint` that acts as kind of Publisher.
  ExtensionPoint | The `ExtensionPoint` provide meta information of a extension point.
  ExtParser | A wrapper that invokes external command to do real parsing job.
  FastURLFilter | Filters URLs based on a file of regular expressions using host/domains matching first.
  FastURLFilter.DenyAllRule | Rule for `DenyPath .*` or `DenyPath .?`
  FastURLFilter.DenyPathQueryRule |
  FastURLFilter.DenyPathRule |
  FastURLFilter.Rule |
  Feed | A collection of Feed property names extracted by the ROME library.
  FeedIndexingFilter |
  FeedParser |
  Fetcher | A queue-based fetcher.
  Fetcher.FetcherRun |
  Fetcher.InputFormat |
  FetcherOutputFormat | Splits FetcherOutput entries into multiple map files.
  FetcherThread | This class picks items from queues and fetches the pages.
  FetcherThreadEvent | This class is used to capture the various events occurring at fetch time.
  FetcherThreadEvent.PublishEventType | Type of event to specify start, end or reporting of a fetch item.
  FetcherThreadPublisher | This class handles the publishing of the events to the queue implementation.
  FetchItem | This class describes the item to be fetched.
  FetchItemQueue | This class handles FetchItems which come from the same host ID (be it a proto/hostname or proto/IP pair).
  FetchItemQueues | A collection of queues that keeps track of the total number of items, and provides items eligible for fetching from any queue.
  FetchNode |
  FetchNodeDb |
  FetchNodeDbInfo |
  FetchOverdueCrawlDatumProcessor | Simple custom crawl datum processor that counts the number of records that are overdue for fetching, e.g.
  FetchSchedule | This interface defines the contract for implementations that manipulate fetch times and re-fetch intervals.
  FetchScheduleFactory | Creates and caches a `FetchSchedule` implementation.
  FieldReplacer | POJO to store a filename, its match pattern and its replacement string.
  File | This class is a protocol plugin used for file: scheme.
  FileDumper | The file dumper tool enables one to reverse generate the raw content from Nutch segment data directories.
  FileError | Thrown for File error codes.
  FileException |
  FileResponse | FileResponse.java mimics file replies as http response.
  FreeGenerator | This tool generates fetchlists (segments to be fetched) from plain text files containing one URL per line.
  FreeGenerator.FG |
  FreeGenerator.FG.FGMapper |
  FreeGenerator.FG.FGReducer |
  FSUtils | Utility methods for common filesystem operations.
  Ftp | This class is a protocol plugin used for ftp: scheme.
  FtpError | Thrown for Ftp error codes.
  FtpException | Superclass for important exceptions thrown during FTP talk, that must be handled with care.
  FtpExceptionBadSystResponse | Exception indicating bad reply of SYST command.
  FtpExceptionCanNotHaveDataConnection | Exception indicating failure of opening data connection.
  FtpExceptionControlClosedByForcedDataClose | Exception indicating control channel is closed by server end, due to forced closure of data channel at client (our) end.
  FtpExceptionUnknownForcedDataClose | Exception indicating unrecognizable reply from server after forced closure of data channel by client (our) side.
  FtpResponse | FtpResponse.java mimics ftp replies as http response.
  FtpRobotRulesParser | This class is used for parsing robots for urls belonging to FTP protocol.
  Generator | Generates a subset of a CrawlDb to fetch.
  Generator.CrawlDbUpdater | Update the CrawlDB so that the next generate won't include the same URLs.
  Generator.CrawlDbUpdater.CrawlDbUpdateMapper |
  Generator.CrawlDbUpdater.CrawlDbUpdateReducer |
  Generator.DecreasingFloatComparator |
  Generator.HashComparator | Sort fetch lists by hash of URL.
  Generator.PartitionReducer |
  Generator.Selector | Selects entries due for fetch.
  Generator.SelectorEntry |
  Generator.SelectorInverseMapper |
  Generator.SelectorMapper | Select and invert subset due for fetch.
  Generator.SelectorReducer | Collect until limit is reached.
  GenericWritableConfigurable | A generic Writable wrapper that can inject Configuration to `Configurable`s
  GeoIPDocumentCreator | Simple utility class which enables efficient, structured `NutchDocument` building based on input from `GeoIPIndexingFilter`, where configuration is also read.
  GeoIPIndexingFilter | This plugin implements an indexing filter which takes advantage of the GeoIP2-java API.
  GZIPUtils | A collection of utility methods for working on GZIPed data.
  HadoopFSUtil |
  HeadingsParseFilter | HtmlParseFilter to retrieve h1 and h2 values from the DOM.
  HostDatum |
  HostURLNormalizer | URL normalizer for mapping hosts to their desired form.
  HTMLLanguageParser |
  HTMLMetaProcessor | Class for parsing META Directives from DOM trees.
  HTMLMetaProcessor | Class for parsing META Directives from DOM trees.
  HTMLMetaTags | This class holds the information about HTML "meta" tags extracted from a page.
  HtmlParseFilter | Extension point for DOM-based HTML parsers.
  HtmlParseFilters | Creates and caches `HtmlParseFilter` implementing plugins.
  HtmlParser |
  HtmlUnitWebDriver |
  HtmlUnitWebWindowListener |
  Http |
  Http |
  Http | This class is a protocol plugin that configures an HTTP client for Basic, Digest and NTLM authentication schemes for web server as well as proxy server.
  Http |
  Http |
  HttpAuthentication | The base level of services required for Http Authentication
  HttpAuthenticationException | Can be used to identify problems during creation of Authentication objects.
  HttpAuthenticationFactory | Provides the Http protocol implementation with the ability to authenticate when prompted.
  HttpBase |
  HttpBasicAuthentication | Implementation of RFC 2617 Basic Authentication.
  HttpDateFormat | Parse and format HTTP dates in HTTP headers, e.g., used to fill the "If-Modified-Since" request header field.
  HttpException |
  HttpFormAuthConfigurer |
  HttpFormAuthentication |
  HttpHeaders | A collection of HTTP header names.
  HttpResponse | An HTTP response.
  HttpResponse | An HTTP response.
  HttpResponse | An HTTP response.
  HttpResponse |
  HttpResponse |
  HttpResponse.Scheme |
  HttpResponse.Scheme |
  HttpResponse.Scheme |
  HttpResponse.Scheme |
  HttpRobotRulesParser | This class is used for parsing robots for urls belonging to HTTP protocol.
  HttpWebClient |
  IndexerMapReduce | This class is typically invoked from within `IndexingJob` and handles all MapReduce functionality required when undertaking indexing.
  IndexerMapReduce.IndexerMapper |
  IndexerMapReduce.IndexerReducer |
  IndexerOutputFormat |
  IndexingException |
  IndexingFilter | Extension point for indexing.
  IndexingFilters | Creates and caches `IndexingFilter` implementing plugins.
  IndexingFiltersChecker | Reads and parses a URL and run the indexers on it.
  IndexingJob | Generic indexer which relies on the plugins implementing IndexWriter
  IndexWriter |
  IndexWriterConfig |
  IndexWriterParams |
  IndexWriters | Creates and caches `IndexWriter` implementing plugins.
  Injector | Injector takes a flat text file of URLs (or a folder containing text files) and merges ("injects") these URLs into the CrawlDb.
  Injector.InjectMapper | InjectMapper reads the CrawlDb seeds are injected into the plain-text seed files and parses each line into the URL and metadata.
  Injector.InjectReducer | Combine multiple new entries for a url.
  Inlink | An incoming link to a page.
  Inlinks | A list of `Inlink`s.
  InteractiveSeleniumHandler |
  IPFilterRules | Optionally limit or block connections to IP address ranges (localhost/loopback or site-local addresses, subnet ranges given in CIDR notation, or single IP addresses).
  JexlExchange |
  JexlIndexingFilter | An `IndexingFilter` that allows filtering of documents based on a JEXL expression.
  JexlUtil | Utility methods for handling JEXL expressions
  JobConfig | Job-specific configuration.
  JobFactory |
  JobInfo | This is the response object containing Job information
  JobInfo.State |
  JobManager |
  JobManager.JobType |
  JobManagerImpl |
  JobResource |
  JobWorker |
  JSParseFilter | This class is a heuristic link extractor for JavaScript files and code snippets.
  KafkaConstants |
  KafkaIndexWriter | Sends Nutch documents to a configured Kafka Cluster
  LanguageIndexingFilter | An `IndexingFilter` that add a `lang` (language) field to the document.
  LinkAnalysisScoringFilter |
  LinkDatum | A class for holding link information including the url, anchor text, a score, the timestamp of the link and a link type.
  LinkDb | Maintains an inverted link map, listing incoming links for each url.
  LinkDb.LinkDbMapper |
  LinkDbFilter | This class provides a way to separate the URL normalization and filtering steps from the rest of LinkDb manipulation code.
  LinkDbMerger | This tool merges several LinkDb-s into one, optionally filtering URLs through the current URLFilters, to skip prohibited URLs and links.
  LinkDbMerger.LinkDbMergeReducer |
  LinkDbReader | Read utility for the LinkDb.
  LinkDbReader.LinkDBDumpMapper |
  LinkDumper | The LinkDumper tool creates a database of node to inlink information that can be read using the nested Reader class.
  LinkDumper.Inverter | Inverts outlinks from the WebGraph to inlinks and attaches node information.
  LinkDumper.Inverter.InvertMapper | Wraps all values in ObjectWritables.
  LinkDumper.Inverter.InvertReducer | Inverts outlinks to inlinks while attaching node information to the outlink.
  LinkDumper.LinkNode | Bean class which holds url to node information.
  LinkDumper.LinkNodes | Writable class which holds an array of LinkNode objects.
  LinkDumper.Merger | Merges LinkNode objects into a single array value per url.
  LinkDumper.Reader | Reader class which will print out the url and all of its inlinks to system out.
  LinkRank |
  LinkReader |
  LinksIndexingFilter | An `IndexingFilter` that adds `outlinks` and `inlinks` field(s) to the document.
  LockUtil | Utility methods for handling application-level locking.
  LuceneAnalyzerUtil | Creates a custom analyzer based on user provided inputs
  LuceneAnalyzerUtil.StemFilterType |
  LuceneTokenizer |
  LuceneTokenizer.TokenizerType |
  MD5Signature | Default implementation of a page signature.
  Metadata | A multi-valued metadata container.
  MetadataIndexer | Indexer which can be configured to extract metadata from the crawldb, parse metadata or content metadata.
  MetadataScoringFilter | For documentation: `org.apache.nutch.scoring.metadata`
  MetaTagsParser | Parse HTML meta tags (keywords, description) and store them in the parse metadata so that they can be indexed with the index-metadata plugin with the prefix 'metatag.'.
  MetaWrapper | This is a simple decorator that adds metadata to any Writable-s that can be serialized by `NutchWritable`.
  MimeAdaptiveFetchSchedule | Extension of @see AdaptiveFetchSchedule that allows for more flexible configuration of DEC and INC factors for various MIME-types.
  MimeTypeIndexingFilter | An `IndexingFilter` that allows filtering of documents based on the MIME Type detected by Tika
  MimeUtil | This is a facade class to insulate Nutch from its underlying Mime Type substrate library, Apache Tika.
  MissingDependencyException | `MissingDependencyException` will be thrown if a plugin dependency cannot be found.
  Model | This class creates a model used to store Document vector representation of the corpus.
  MoreIndexingFilter | Add (or reset) a few metaData properties as respective fields (if they are available), so that they can be accurately used within the search index.
  NaiveBayesParseFilter | Html Parse filter that classifies the outlinks from the parseresult as relevant or irrelevant based on the parseText's relevancy (using a training file where you can give positive and negative example texts see the description of parsefilter.naivebayes.trainfile) and if found irrelevant it gives the link a second chance if it contains any of the words from the list given in parsefilter.naivebayes.wordlist.
  Node | A class which holds the number of inlinks and outlinks for a given url along with an inlink score from a link analysis program and any metadata.
  NodeDumper | A tools that dumps out the top urls by number of inlinks, number of outlinks, or by score, to a text file.
  NodeDumper.Dumper | Outputs the hosts or domains with an associated value.
  NodeDumper.Dumper.DumperMapper | Outputs the host or domain as key for this record and numInlinks, numOutlinks or score as the value.
  NodeDumper.Dumper.DumperReducer | Outputs either the sum or the top value for this record.
  NodeDumper.Sorter | Outputs the top urls sorted in descending order.
  NodeDumper.Sorter.SorterMapper | Outputs the url with the appropriate number of inlinks, outlinks, or for score.
  NodeDumper.Sorter.SorterReducer | Flips and collects the url and numeric sort value.
  NodeReader | Reads and prints to system out information for a single node from the NodeDb in the WebGraph.
  NodeReader |
  NodeWalker | A utility class that allows the walking of any DOM tree using a stack instead of recursion.
  Nutch | A collection of Nutch internal metadata constants.
  NutchConfig |
  NutchConfiguration | Utility to create Hadoop `Configuration`s that include Nutch-specific resources.
  NutchDocument | A `NutchDocument` is the unit of indexing.
  NutchField | This class represents a multi-valued field with a weight.
  NutchIndexAction | A `NutchIndexAction` is the new unit of indexing holding the document and action information.
  NutchJob | A `Job` for Nutch jobs.
  NutchPublisher | All publisher subscriber model implementations should implement this interface.
  NutchPublishers |
  NutchReader |
  NutchServer |
  NutchServerInfo |
  NutchServerPoolExecutor |
  NutchTool |
  NutchWritable |
  ObjectCache |
  OkHttp |
  OkHttpResponse |
  OkHttpResponse.TruncatedContent | Container to store whether and why content has been truncated
  OpenSearch1xConstants |
  OpenSearch1xIndexWriter | Sends NutchDocuments to a configured OpenSearch index.
  OPICScoringFilter | This plugin implements a variant of an Online Page Importance Computation (OPIC) score, described in this paper: Abiteboul, Serge and Preda, Mihai and Cobena, Gregory (2003), Adaptive On-Line Page Importance Computation.
  OrphanScoringFilter | Orphan scoring filter that determines whether a page has become orphaned, e.g.
  Outlink | An outgoing link from a page.
  OutlinkExtractor | Extractor to extract `Outlink`s / URLs from plain text using Regular Expressions.
  Parse | The result of parsing a page's raw content.
  ParseData | Data extracted from a page's content.
  ParseException |
  ParseImpl | The result of parsing a page's raw content.
  ParseOutputFormat |
  Parser | A parser for content generated by a `Protocol` implementation.
  ParserChecker | Parser checker, useful for testing parser.
  ParseResult | A utility class that stores result of a parse.
  ParserFactory | Creates and caches `Parser` plugins.
  ParserNotFound |
  ParseSegment |
  ParseSegment.ParseSegmentMapper |
  ParseSegment.ParseSegmentReducer |
  ParseStatus |
  ParseText |
  ParseUtil | A Utility class containing methods to simply perform parsing utilities such as iterating through a preferred list of `Parser`s to obtain `Parse` objects.
  PassURLNormalizer | This URLNormalizer doesn't change urls.
  Pluggable | Defines the capability of a class to be plugged into Nutch.
  Plugin | A nutch-plugin is an container for a set of custom logic that provide extensions to the nutch core functionality or another plugin that provides an API for extending.
  PluginClassLoader | The `PluginClassLoader` is a child-first classloader that only contains classes of the runtime libraries setuped in the plugin manifest file and exported libraries of plugins that are required plugins.
  PluginDescriptor | The `PluginDescriptor` provide access to all meta information of a nutch-plugin, as well to the internationalizable resources and the plugin own classloader.
  PluginManifestParser | The `PluginManifestParser` provides a mechanism for parsing Nutch plugin manifest files (`plugin.xml`) contained in a `String` of plugin directories.
  PluginRepository | The plugin repository is a registry of all plugins.
  PluginRuntimeException | `PluginRuntimeException` will be thrown until a exception in the plugin managemnt occurs.
  PrefixStringMatcher | A class for efficiently matching `String`s against a set of prefixes.
  PrefixURLFilter | Filters URLs based on a file of URL prefixes.
  PrintCommandListener | This is a support class for logging all ftp command/reply traffic.
  Protocol | A retriever of url content.
  ProtocolException | Deprecated. Use `ProtocolException` instead.
  ProtocolException |
  ProtocolFactory | Creates and caches `Protocol` plugins.
  ProtocolLogUtil |
  ProtocolNotFound |
  ProtocolOutput | Simple aggregate to pass from protocol plugins both content and protocol status.
  ProtocolStatus |
  ProtocolStatusStatistics | Extracts protocol status code information from the crawl database.
  ProtocolStatusStatistics.ProtocolStatusStatisticsCombiner |
  ProtocolURLNormalizer | URL normalizer to normalize the protocol for all URLs of a given host or domain, e.g.
  QuerystringURLNormalizer | URL normalizer plugin for normalizing query strings but sorting query string parameters.
  QueueFeeder | This class feeds the queues with input items, and re-fills them as items are consumed by FetcherThread-s.
  RabbitIndexWriter |
  RabbitMQClient | Client for RabbitMQ
  RabbitMQMessage |
  RabbitMQPublisherImpl |
  ReaderConfig |
  ReaderResouce | The Reader endpoint enables a user to read sequence files, nodes and links from the Nutch webgraph.
  ReadHostDb |
  RegexParseFilter | RegexParseFilter.
  RegexRule | A generic regular expression rule.
  RegexURLFilter | Filters URLs based on a file of regular expressions using the `Java Regex implementation`.
  RegexURLFilterBase | Generic `URLFilter` based on regular expressions.
  RegexURLNormalizer | Allows users to do regex substitutions on all/any URLs that are encountered, which is useful for stripping session IDs from URLs.
  RelTagIndexingFilter | An `IndexingFilter` that add `tag` field(s) to the document.
  RelTagParser | Adds microformat rel-tags of document if found.
  ReplaceIndexer | Do pattern replacements on selected field contents prior to indexing.
  ResolverThread | Simple runnable that performs DNS lookup for a single host.
  ResolveUrls | A simple tool that will spin up multiple threads to resolve urls to ip addresses.
  Response | A response interface.
  Response.TruncatedContentReason |
  RobotRulesParser | This class uses crawler-commons for handling the parsing of `robots.txt` files.
  ScoreUpdater | Updates the score from the WebGraph node database into the crawl database.
  ScoreUpdater.ScoreUpdaterMapper | Changes input into ObjectWritables.
  ScoreUpdater.ScoreUpdaterReducer | Creates new CrawlDatum objects with the updated score from the NodeDb or with a cleared score.
  ScoringFilter | A contract defining behavior of scoring plugins.
  ScoringFilterException | Specialized exception for errors during scoring.
  ScoringFilters | Creates and caches `ScoringFilter` implementing plugins.
  SeedList |
  SeedManager |
  SeedManagerImpl |
  SeedResource |
  SeedUrl |
  SegmentChecker | Checks whether a segment is valid, or has a certain status (generated, fetched, parsed), or can be used safely for a certain processing step (e.g., indexing).
  SegmentMergeFilter | Interface used to filter segments during segment merge.
  SegmentMergeFilters | This class wraps all `SegmentMergeFilter` extensions in a single object so it is easier to operate on them.
  SegmentMerger | This tool takes several segments and merges their data together.
  SegmentMerger.ObjectInputFormat | Wraps inputs in an `MetaWrapper`, to permit merging different types in reduce and use additional metadata.
  SegmentMerger.SegmentMergerMapper |
  SegmentMerger.SegmentMergerReducer | NOTE: in selecting the latest version we rely exclusively on the segment name (not all segment data contain time information).
  SegmentMerger.SegmentOutputFormat |
  SegmentPart | Utility class for handling information about segment parts.
  SegmentReader | Dump the content of a segment.
  SegmentReader.InputCompatMapper |
  SegmentReader.InputCompatReducer |
  SegmentReader.SegmentReaderStats |
  SegmentReader.TextOutputFormat | Implements a text output format
  SegmentReaderUtil |
  SequenceReader | Enables reading a sequence file and methods provide different ways to read the file.
  ServiceConfig |
  ServiceInfo |
  ServicesResource | The services resource defines an endpoint to enable the user to carry out Nutch jobs like dump, commoncrawldump, etc.
  ServiceWorker |
  ShowProperties | Tool to list properties and their values set by the current Nutch configuration
  Signature |
  SignatureComparator |
  SignatureFactory | Factory class, which instantiates a Signature implementation according to the current Configuration configuration.
  SimilarityModel |
  SimilarityScoringFilter |
  SitemapProcessor | Performs sitemap processing by fetching sitemap links, parsing the content and merging the URLs from sitemaps (with the metadata) into the CrawlDb.
  SlashURLNormalizer |
  SolrConstants |
  SolrIndexWriter |
  SolrUtils |
  SpellCheckedMetadata | A decorator to Metadata that adds spellchecking capabilities to property names.
  StaticFieldIndexer | A simple plugin called at indexing that adds fields with static data.
  StringUtil | A collection of String processing utility methods.
  Subcollection | SubCollection represents a subset of index, you can define url patterns that will indicate that particular page (url) is part of SubCollection.
  SubcollectionIndexingFilter |
  SuffixStringMatcher | A class for efficiently matching `String`s against a set of suffixes.
  SuffixURLFilter | Filters URLs based on a file of URL suffixes.
  TableUtil |
  TextMD5Signature | Implementation of a page signature.
  TextProfileSignature | An implementation of a page signature.
  TikaParser | Wrapper for Tika parsers.
  TimingUtil |
  TLDIndexingFilter | Adds the public suffix (aka.
  Train |
  TrieStringMatcher | TrieStringMatcher is a base class for simple tree-based string matching.
  UpdateHostDb | Tool to create a HostDB from the CrawlDB.
  UpdateHostDbMapper | Mapper ingesting HostDB and CrawlDB entries.
  UpdateHostDbReducer |
  URLExemptionFilter | Interface used to allow exemptions to external domain resources by overriding `db.ignore.external.links`.
  URLExemptionFilters | Creates and caches `URLExemptionFilter` implementing plugins.
  URLFilter | Interface used to limit which URLs enter Nutch.
  URLFilterChecker | Checks one given filter or all filters.
  URLFilterException |
  URLFilters | Creates and caches plugins implementing `URLFilter`.
  URLMetaIndexingFilter | This is part of the URL Meta plugin.
  URLMetaScoringFilter | For documentation: `org.apache.nutch.scoring.urlmeta`
  URLNormalizer | Interface used to convert URLs to normal form and optionally perform substitutions
  URLNormalizerChecker | Checks one given normalizer or all normalizers.
  URLNormalizers | This class uses a "chained filter" pattern to run defined normalizers.
  URLPartitioner | Partition urls by host, domain name or IP depending on the value of the parameter 'partition.url.mode' which can be 'byHost', 'byDomain' or 'byIP'
  URLStreamHandlerFactory | This URLStreamHandlerFactory knows about all the plugins in use and thus can create the correct URLStreamHandler even if it comes from a plugin classpath.
  URLUtil | Utility class for URL analysis
  UrlValidator | Validates URLs.
  WARCExporter | MapReduce job to exports Nutch segments as WARC files.
  WARCExporter.WARCMapReduce |
  WARCExporter.WARCMapReduce.WARCMapper |
  WARCExporter.WARCMapReduce.WARCReducer |
  WARCUtils |
  WebGraph | Creates three databases, one for inlinks, one for outlinks, and a node database that holds the number of in and outlinks to a url and the current score for the url.
  WebGraph.OutlinkDb | The OutlinkDb creates a database of all outlinks.
  WebGraph.OutlinkDb.OutlinkDbMapper | Passes through existing LinkDatum objects from an existing OutlinkDb and maps out new LinkDatum objects from new crawls ParseData.
  WebGraph.OutlinkDb.OutlinkDbReducer |
  XMLCharacterRecognizer | Class used to verify whether the specified ch conforms to the XML 1.0 definition of whitespace.
  ZipParser | ZipParser class based on MSPowerPointParser class by Stephan Strittmatter.
  ZipTextExtractor |