Package com.yahoo.prelude.query.parser

Class AbstractParser

java.lang.Object
com.yahoo.prelude.query.parser.AbstractParser
All Implemented Interfaces:
CustomParser, Parser
Direct Known Subclasses:
AdvancedParser, AllParser, AnyParser, PhraseParser, TokenizeParser
public abstract class AbstractParser extends Object implements CustomParser
The Vespa query parser.
Author:
bratseth, Steinar Knutsen

  • Field Details

    • submodes

      protected com.yahoo.prelude.query.parser.AbstractParser.Submodes submodes
      The current submodes of this parser

    • language

      protected com.yahoo.language.Language language
      The current language of this parser. Used to decide whether and how to use the CJKSegmenter

    • indexFacts

      protected IndexFacts.Session indexFacts
      The IndexFacts.Session of this query

    • defaultIndex

      protected String defaultIndex

    • braceLevelURL

      protected int braceLevelURL
      The counter for braces in URLs, braces in URLs are accepted so long as they are balanced.

    • environment

      protected final ParserEnvironment environment

    • tokens

      protected final com.yahoo.prelude.query.parser.TokenPosition tokens

  • Constructor Details

    • AbstractParser

      protected AbstractParser(ParserEnvironment environment)
      Creates a new instance of this class, storing the given ParserEnvironment for parse-time access to the environment.
      Parameters:
      environment - the environment settings to attach to the Parser

  • Method Details

    • parse

      public final QueryTree parse(Parsable query)
      Description copied from interface: Parser
      Parser the given Parsable, and returns a corresponding QueryTree. If parsing fails without an exception, the contained root will be an instance of NullItem.
      Specified by:
      parse in interface Parser
      Parameters:
      query - the Parsable to parse
      Returns:
      the parsed QueryTree, never null

    • parse

      public final Item parse(String queryToParse, String filterToParse, com.yahoo.language.Language parsingLanguage, IndexFacts.Session indexFacts, String defaultIndex)
      Specified by:
      parse in interface CustomParser

    • parseItems

      protected abstract Item parseItems()

    • normalize

      protected String normalize(String input)
      Unicode normalizes some piece of natural language text. The chosen form is compatibility decomposition, canonical composition (NFKC).

    • setState

      protected void setState(com.yahoo.language.Language queryLanguage, IndexFacts.Session indexFacts, String defaultIndex)

    • tokenize

      protected void tokenize(String query, String defaultIndexName, IndexFacts.Session indexFacts, com.yahoo.language.Language language)
      Tokenizes the given string and initializes tokens with the found tokens.
      Parameters:
      query - the string to tokenize
      defaultIndexName - the name of the index to use as default
      indexFacts - resolved information about the index we are searching
      language - the language set for this query, or null if none

    • simplifyPhrases

      public static Item simplifyPhrases(Item unwashed)
      Collapses single item phrases in the tree to the contained item.
      Parameters:
      unwashed - The item whose phrases to simplify.
      Returns:
      The simplified item.

    • segment

      protected Item segment(String indexName, Token token, boolean quoted)
      Segments a token
      Parameters:
      indexName - the index name which preceeded this token, or null if none
      token - the token to segment
      quoted - whether this segment is within quoted text
      Returns:
      the resulting item