| /* |
| * 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. |
| */ |
| package org.apache.lucene.queryparser.ext; |
| |
| import org.apache.lucene.analysis.Analyzer; |
| import org.apache.lucene.queryparser.classic.ParseException; |
| import org.apache.lucene.queryparser.classic.QueryParser; |
| import org.apache.lucene.queryparser.ext.Extensions.Pair; |
| import org.apache.lucene.search.Query; |
| |
| /** |
| * The {@link 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 {@link |
| * ExtendableQueryParser} allows to encode extension keys into the field symbol associated with a |
| * registered instance of {@link ParserExtension}. A customizable separation character separates the |
| * extension key from the actual field symbol. The {@link ExtendableQueryParser} splits (@see {@link |
| * Extensions#splitExtensionField(String, String)}) the extension key from the field symbol and |
| * tries to resolve the associated {@link ParserExtension}. If the parser can't resolve the key or |
| * the field token does not contain a separation character, {@link ExtendableQueryParser} yields the |
| * same behavior as its super class {@link QueryParser}. Otherwise, if the key is associated with a |
| * {@link ParserExtension} instance, the parser builds an instance of {@link ExtensionQuery} to be |
| * processed by {@link ParserExtension#parse(ExtensionQuery)}.If a extension field does not contain |
| * a field part the default field for the query will be used. |
| * |
| * <p>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): |
| * |
| * <pre> |
| * title_customExt:"Apache Lucene\?" OR content_customExt:prefix\* |
| * </pre> |
| * |
| * Search on the default field: |
| * |
| * <pre> |
| * _customExt:"Apache Lucene\?" OR _customExt:prefix\* |
| * </pre> |
| * |
| * <p>The {@link 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 {@link Extensions}. Customized extension schemes should be implemented by sub-classing |
| * {@link Extensions}. |
| * |
| * <p>For details about the default encoding scheme see {@link Extensions}. |
| * |
| * @see Extensions |
| * @see ParserExtension |
| * @see ExtensionQuery |
| */ |
| public class ExtendableQueryParser extends QueryParser { |
| |
| private final String defaultField; |
| private final Extensions extensions; |
| |
| /** Default empty extensions instance */ |
| private static final Extensions DEFAULT_EXTENSION = new Extensions(); |
| |
| /** |
| * Creates a new {@link ExtendableQueryParser} instance |
| * |
| * @param f the default query field |
| * @param a the analyzer used to find terms in a query string |
| */ |
| public ExtendableQueryParser(final String f, final Analyzer a) { |
| this(f, a, DEFAULT_EXTENSION); |
| } |
| |
| /** |
| * Creates a new {@link ExtendableQueryParser} instance |
| * |
| * @param f the default query field |
| * @param a the analyzer used to find terms in a query string |
| * @param ext the query parser extensions |
| */ |
| public ExtendableQueryParser(final String f, final Analyzer a, final Extensions ext) { |
| super(f, a); |
| this.defaultField = f; |
| this.extensions = ext; |
| } |
| |
| /** |
| * Returns the extension field delimiter character. |
| * |
| * @return the extension field delimiter character. |
| */ |
| public char getExtensionFieldDelimiter() { |
| return extensions.getExtensionFieldDelimiter(); |
| } |
| |
| @Override |
| protected Query getFieldQuery(final String field, final String queryText, boolean quoted) |
| throws ParseException { |
| final Pair<String, String> splitExtensionField = |
| this.extensions.splitExtensionField(defaultField, field); |
| final ParserExtension extension = this.extensions.getExtension(splitExtensionField.cud); |
| if (extension != null) { |
| return extension.parse(new ExtensionQuery(this, splitExtensionField.cur, queryText)); |
| } |
| return super.getFieldQuery(field, queryText, quoted); |
| } |
| } |