Package org.apache.lucene.analysis.miscellaneous

Class PatternAnalyzer

java.lang.Object
org.apache.lucene.analysis.Analyzer
org.apache.lucene.analysis.miscellaneous.PatternAnalyzer
All Implemented Interfaces:
Closeable, AutoCloseable
@Deprecated public final class PatternAnalyzer extends Analyzer
Deprecated.
(4.0) use the pattern-based analysis in the analysis/pattern package instead.
Efficient Lucene analyzer/tokenizer that preferably operates on a String rather than a Reader, that can flexibly separate text into terms via a regular expression Pattern (with behaviour identical to String.split(String)), and that combines the functionality of LetterTokenizer, LowerCaseTokenizer, WhitespaceTokenizer, StopFilter into a single efficient multi-purpose class.

If you are unsure how exactly a regular expression should look like, consider prototyping by simply trying various expressions on some test texts via String.split(String). Once you are satisfied, give that regex to PatternAnalyzer. Also see Java Regular Expression Tutorial.

This class can be considerably faster than the "normal" Lucene tokenizers. It can also serve as a building block in a compound Lucene TokenFilter chain. For example as in this stemming example: 

 PatternAnalyzer pat = ...
 TokenStream tokenStream = new SnowballFilter(
     pat.tokenStream("content", "James is running round in the woods"), 
     "English"));

  • Field Details

    • NON_WORD_PATTERN

      public static final Pattern NON_WORD_PATTERN
      Deprecated.
      "\\W+"; Divides text at non-letters (NOT Character.isLetter(c))

    • WHITESPACE_PATTERN

      public static final Pattern WHITESPACE_PATTERN
      Deprecated.
      "\\s+"; Divides text at whitespaces (Character.isWhitespace(c))

    • DEFAULT_ANALYZER

      public static final PatternAnalyzer DEFAULT_ANALYZER
      Deprecated.
      A lower-casing word analyzer with English stop words (can be shared freely across threads without harm); global per class loader.

    • EXTENDED_ANALYZER

      public static final PatternAnalyzer EXTENDED_ANALYZER
      Deprecated.
      A lower-casing word analyzer with extended English stop words (can be shared freely across threads without harm); global per class loader. The stop words are borrowed from http://thomas.loc.gov/home/stopwords.html, see http://thomas.loc.gov/home/all.about.inquery.html

  • Constructor Details

    • PatternAnalyzer

      public PatternAnalyzer(Version matchVersion, Pattern pattern, boolean toLowerCase, CharArraySet stopWords)
      Deprecated.
      Constructs a new instance with the given parameters.
      Parameters:
      matchVersion - currently does nothing
      pattern - a regular expression delimiting tokens
      toLowerCase - if true returns tokens after applying String.toLowerCase()
      stopWords - if non-null, ignores all tokens that are contained in the given stop set (after previously having applied toLowerCase() if applicable). For example, created via StopFilter.makeStopSet(Version, String[])and/or WordlistLoaderas in WordlistLoader.getWordSet(new File("samples/fulltext/stopwords.txt") or other stop words lists .

  • Method Details

    • createComponents

      public Analyzer.TokenStreamComponents createComponents(String fieldName, Reader reader, String text)
      Deprecated.
      Creates a token stream that tokenizes the given string into token terms (aka words).
      Parameters:
      fieldName - the name of the field to tokenize (currently ignored).
      reader - reader (e.g. charfilter) of the original text. can be null.
      text - the string to tokenize
      Returns:
      a new token stream

    • createComponents

      public Analyzer.TokenStreamComponents createComponents(String fieldName, Reader reader)
      Deprecated.
      Creates a token stream that tokenizes all the text in the given Reader; This implementation forwards to tokenStream(String, Reader, String) and is less efficient than tokenStream(String, Reader, String).
      Parameters:
      fieldName - the name of the field to tokenize (currently ignored).
      reader - the reader delivering the text
      Returns:
      a new token stream

    • equals

      public boolean equals(Object other)
      Deprecated.
      Indicates whether some other object is "equal to" this one.
      Overrides:
      equals in class Object
      Parameters:
      other - the reference object with which to compare.
      Returns:
      true if equal, false otherwise

    • hashCode

      public int hashCode()
      Deprecated.
      Returns a hash code value for the object.
      Overrides:
      hashCode in class Object
      Returns:
      the hash code.