| /* |
| * 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.search; |
| |
| |
| import org.apache.lucene.index.Term; |
| import org.apache.lucene.util.automaton.Automaton; |
| import org.apache.lucene.util.automaton.AutomatonProvider; |
| import org.apache.lucene.util.automaton.Operations; |
| import org.apache.lucene.util.automaton.RegExp; |
| |
| /** |
| * A fast regular expression query based on the |
| * {@link org.apache.lucene.util.automaton} package. |
| * <ul> |
| * <li>Comparisons are <a |
| * href="http://tusker.org/regex/regex_benchmark.html">fast</a> |
| * <li>The term dictionary is enumerated in an intelligent way, to avoid |
| * comparisons. See {@link AutomatonQuery} for more details. |
| * </ul> |
| * <p> |
| * The supported syntax is documented in the {@link RegExp} class. |
| * Note this might be different than other regular expression implementations. |
| * For some alternatives with different syntax, look under the sandbox. |
| * </p> |
| * <p> |
| * Note this query can be slow, as it needs to iterate over many terms. In order |
| * to prevent extremely slow RegexpQueries, a Regexp term should not start with |
| * the expression <code>.*</code> |
| * |
| * @see RegExp |
| * @lucene.experimental |
| */ |
| public class RegexpQuery extends AutomatonQuery { |
| /** |
| * A provider that provides no named automata |
| */ |
| private static AutomatonProvider defaultProvider = new AutomatonProvider() { |
| @Override |
| public Automaton getAutomaton(String name) { |
| return null; |
| } |
| }; |
| |
| /** |
| * Constructs a query for terms matching <code>term</code>. |
| * <p> |
| * By default, all regular expression features are enabled. |
| * </p> |
| * |
| * @param term regular expression. |
| */ |
| public RegexpQuery(Term term) { |
| this(term, RegExp.ALL); |
| } |
| |
| /** |
| * Constructs a query for terms matching <code>term</code>. |
| * |
| * @param term regular expression. |
| * @param flags optional RegExp features from {@link RegExp} |
| */ |
| public RegexpQuery(Term term, int flags) { |
| this(term, flags, defaultProvider, |
| Operations.DEFAULT_DETERMINIZE_WORK_LIMIT); |
| } |
| |
| /** |
| * Constructs a query for terms matching <code>term</code>. |
| * |
| * @param term regular expression. |
| * @param flags optional RegExp syntax features from {@link RegExp} |
| * @param determinizeWorkLimit maximum effort to spend while compiling the automaton from this |
| * regexp. Set higher to allow more complex queries and lower to prevent memory exhaustion. |
| * Use {@link Operations#DEFAULT_DETERMINIZE_WORK_LIMIT} as a decent default if you don't |
| * otherwise know what to specify. |
| */ |
| public RegexpQuery(Term term, int flags, int determinizeWorkLimit) { |
| this(term, flags, defaultProvider, determinizeWorkLimit); |
| } |
| |
| /** |
| * Constructs a query for terms matching <code>term</code>. |
| * |
| * @param term regular expression. |
| * @param syntax_flags optional RegExp syntax features from {@link RegExp} |
| * automaton for the regexp can result in. Set higher to allow more complex |
| * queries and lower to prevent memory exhaustion. |
| * @param match_flags boolean 'or' of match behavior options such as case insensitivity |
| * @param determinizeWorkLimit maximum effort to spend while compiling the automaton from this |
| * regexp. Set higher to allow more complex queries and lower to prevent memory exhaustion. |
| * Use {@link Operations#DEFAULT_DETERMINIZE_WORK_LIMIT} as a decent default if you don't |
| * otherwise know what to specify. |
| */ |
| public RegexpQuery(Term term, int syntax_flags, int match_flags, int determinizeWorkLimit) { |
| this(term, syntax_flags, match_flags, defaultProvider, determinizeWorkLimit); |
| } |
| |
| /** |
| * Constructs a query for terms matching <code>term</code>. |
| * |
| * @param term regular expression. |
| * @param syntax_flags optional RegExp features from {@link RegExp} |
| * @param provider custom AutomatonProvider for named automata |
| * @param determinizeWorkLimit maximum effort to spend while compiling the automaton from this |
| * regexp. Set higher to allow more complex queries and lower to prevent memory exhaustion. |
| * Use {@link Operations#DEFAULT_DETERMINIZE_WORK_LIMIT} as a decent default if you don't |
| * otherwise know what to specify. |
| */ |
| public RegexpQuery(Term term, int syntax_flags, AutomatonProvider provider, |
| int determinizeWorkLimit) { |
| this(term, syntax_flags, 0, provider, determinizeWorkLimit); |
| } |
| |
| /** |
| * Constructs a query for terms matching <code>term</code>. |
| * |
| * @param term regular expression. |
| * @param syntax_flags optional RegExp features from {@link RegExp} |
| * @param match_flags boolean 'or' of match behavior options such as case insensitivity |
| * @param provider custom AutomatonProvider for named automata |
| * @param determinizeWorkLimit maximum effort to spend while compiling the automaton from this |
| * regexp. Set higher to allow more complex queries and lower to prevent memory exhaustion. |
| * Use {@link Operations#DEFAULT_DETERMINIZE_WORK_LIMIT} as a decent default if you don't |
| * otherwise know what to specify. |
| */ |
| public RegexpQuery(Term term, int syntax_flags, int match_flags, AutomatonProvider provider, |
| int determinizeWorkLimit) { |
| super(term, |
| new RegExp(term.text(), syntax_flags, match_flags).toAutomaton( |
| provider, determinizeWorkLimit), determinizeWorkLimit); |
| } |
| |
| /** Returns the regexp of this query wrapped in a Term. */ |
| public Term getRegexp() { |
| return term; |
| } |
| |
| /** Prints a user-readable version of this query. */ |
| @Override |
| public String toString(String field) { |
| StringBuilder buffer = new StringBuilder(); |
| if (!term.field().equals(field)) { |
| buffer.append(term.field()); |
| buffer.append(":"); |
| } |
| buffer.append('/'); |
| buffer.append(term.text()); |
| buffer.append('/'); |
| return buffer.toString(); |
| } |
| } |