Package org.apache.lucene.queryparser.ext

Class ExtendableQueryParser

java.lang.Object
org.apache.lucene.util.QueryBuilder
org.apache.lucene.queryparser.classic.QueryParserBase
org.apache.lucene.queryparser.classic.QueryParser
org.apache.lucene.queryparser.ext.ExtendableQueryParser
All Implemented Interfaces:
QueryParserConstants, CommonQueryParserConfiguration
public class ExtendableQueryParser extends QueryParser
The ExtendableQueryParser enables arbitrary query parser extension based on a customizable field naming scheme. The lucene query syntax allows implicit and explicit field definitions as query prefix followed by a colon (':') character. The ExtendableQueryParser allows to encode extension keys into the field symbol associated with a registered instance of ParserExtension. A customizable separation character separates the extension key from the actual field symbol. The ExtendableQueryParser splits (@see Extensions.splitExtensionField(String, String)) the extension key from the field symbol and tries to resolve the associated ParserExtension. If the parser can't resolve the key or the field token does not contain a separation character, ExtendableQueryParser yields the same behavior as its super class QueryParser. Otherwise, if the key is associated with a ParserExtension instance, the parser builds an instance of ExtensionQuery to be processed by ParserExtension.parse(ExtensionQuery).If a extension field does not contain a field part the default field for the query will be used.

To guarantee that an extension field is processed with its associated extension, the extension query part must escape any special characters like '*' or '['. If the extension query contains any whitespace characters, the extension query part must be enclosed in quotes. Example ('_' used as separation character): 

   title_customExt:"Apache Lucene\?" OR content_customExt:prefix\*
Search on the default field: 
   _customExt:"Apache Lucene\?" OR _customExt:prefix\*

The ExtendableQueryParser itself does not implement the logic how field and extension key are separated or ordered. All logic regarding the extension key and field symbol parsing is located in Extensions. Customized extension schemes should be implemented by sub-classing Extensions.

For details about the default encoding scheme see Extensions.

See Also:

  • Field Details

    • defaultField

      private final String defaultField

    • extensions

      private final Extensions extensions

    • DEFAULT_EXTENSION

      private static final Extensions DEFAULT_EXTENSION
      Default empty extensions instance

  • Constructor Details

    • ExtendableQueryParser

      public ExtendableQueryParser(String f, Analyzer a)
      Creates a new ExtendableQueryParser instance
      Parameters:
      f - the default query field
      a - the analyzer used to find terms in a query string

    • ExtendableQueryParser

      public ExtendableQueryParser(String f, Analyzer a, Extensions ext)
      Creates a new ExtendableQueryParser instance
      Parameters:
      f - the default query field
      a - the analyzer used to find terms in a query string
      ext - the query parser extensions

  • Method Details

    • getExtensionFieldDelimiter

      public char getExtensionFieldDelimiter()
      Returns the extension field delimiter character.
      Returns:
      the extension field delimiter character.

    • getFieldQuery

      protected Query getFieldQuery(String field, String queryText, boolean quoted) throws ParseException
      Overrides:
      getFieldQuery in class QueryParserBase
      Throws:
      ParseException - throw in overridden method to disallow