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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* Core classes of the flexible query parser framework.
*
* <h2>Flexible Query Parser</h2>
*
* <p>This package contains the necessary classes to implement a query parser.
*
* <p>A query parser is divided in at least 2 phases, text parsing and query building, and one
* optional phase called query processing.
*
* <h3>First Phase: Text Parsing</h3>
*
* <p>The text parsing phase is performed by a text parser, which implements {@link
* org.apache.lucene.queryparser.flexible.core.parser.SyntaxParser} interface. A text parser is
* responsible to get a query string and convert it to a {@link
* org.apache.lucene.queryparser.flexible.core.nodes.QueryNode} tree, which is an object structure
* that represents the elements defined in the query string.
*
* <h3>Second (optional) Phase: Query Processing</h3>
*
* <p>The query processing phase is performed by a query processor, which implements {@link
* org.apache.lucene.queryparser.flexible.core.processors.QueryNodeProcessor}. A query processor is
* responsible to perform any processing on a {@link
* org.apache.lucene.queryparser.flexible.core.nodes.QueryNode} tree. This phase is optional and is
* used only if an extra processing, validation, query expansion, etc needs to be performed in a
* {@link org.apache.lucene.queryparser.flexible.core.nodes.QueryNode} tree. The {@link
* org.apache.lucene.queryparser.flexible.core.nodes.QueryNode} tree can be either be generated by a
* text parser or programmatically created.
*
* <h3>Third Phase: Query Building</h3>
*
* <p>The query building phase is performed by a query builder, which implements {@link
* org.apache.lucene.queryparser.flexible.core.builders.QueryBuilder}. A query builder is
* responsible to convert a {@link org.apache.lucene.queryparser.flexible.core.nodes.QueryNode} tree
* into an arbitrary object, which is usually used to be executed against a search index.
*/
package org.apache.lucene.queryparser.flexible.core;