Package org.apache.lucene.queryparser.flexible.core

Core classes of the flexible query parser framework.

See: Description

Class Summary

Class	Description
QueryParserHelper	This class is a helper for the query parser framework, it does all the three query parser phrases at once: text parsing, query processing and query building.

Exception Summary

Exception	Description
QueryNodeException	This exception should be thrown if something wrong happens when dealing with QueryNodes.
QueryNodeParseException	This should be thrown when an exception happens during the query parsing from string to the query node tree.

Error Summary

Error	Description
QueryNodeError	Error class with NLS support

Package org.apache.lucene.queryparser.flexible.core Description

Core classes of the flexible query parser framework.

Flexible Query Parser

This package contains the necessary classes to implement a query parser.

A query parser is divided in at least 2 phases, text parsing and query building, and one optional phase called query processing.

First Phase: Text Parsing

The text parsing phase is performed by a text parser, which implements SyntaxParser interface. A text parser is responsible to get a query string and convert it to a QueryNode tree, which is an object structure that represents the elements defined in the query string.

Second (optional) Phase: Query Processing

The query processing phase is performed by a query processor, which implements QueryNodeProcessor. A query processor is responsible to perform any processing on a QueryNode tree. This phase is optional and is used only if an extra processing, validation, query expansion, etc needs to be performed in a QueryNode tree. The QueryNode tree can be either be generated by a text parser or programmatically created.

Third Phase: Query Building

The query building phase is performed by a query builder, which implements QueryBuilder. A query builder is responsible to convert a QueryNode tree into an arbitrary object, which is usually used to be executed against a search index.