| using System; |
| using System.Text; |
| |
| namespace Lucene.Net.Search |
| { |
| /* |
| * 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. |
| */ |
| |
| using AttributeSource = Lucene.Net.Util.AttributeSource; |
| using Term = Lucene.Net.Index.Term; |
| using Terms = Lucene.Net.Index.Terms; |
| using TermsEnum = Lucene.Net.Index.TermsEnum; |
| using ToStringUtils = Lucene.Net.Util.ToStringUtils; |
| |
| /// <summary> |
| /// A <see cref="Query"/> that matches documents containing terms with a specified prefix. A <see cref="PrefixQuery"/> |
| /// is built by QueryParser for input like <c>app*</c>. |
| /// |
| /// <para/>This query uses the |
| /// <see cref="MultiTermQuery.CONSTANT_SCORE_AUTO_REWRITE_DEFAULT"/> |
| /// rewrite method. |
| /// </summary> |
| public class PrefixQuery : MultiTermQuery |
| { |
| private readonly Term _prefix; |
| |
| /// <summary> |
| /// Constructs a query for terms starting with <paramref name="prefix"/>. </summary> |
| public PrefixQuery(Term prefix) |
| : base(prefix.Field) |
| { |
| this._prefix = prefix; |
| } |
| |
| /// <summary> |
| /// Returns the prefix of this query. </summary> |
| public virtual Term Prefix => _prefix; |
| |
| protected override TermsEnum GetTermsEnum(Terms terms, AttributeSource atts) |
| { |
| TermsEnum tenum = terms.GetEnumerator(); |
| |
| if (_prefix.Bytes.Length == 0) |
| { |
| // no prefix -- match all terms for this field: |
| return tenum; |
| } |
| return new PrefixTermsEnum(tenum, _prefix.Bytes); |
| } |
| |
| /// <summary> |
| /// Prints a user-readable version of this query. </summary> |
| public override string ToString(string field) |
| { |
| StringBuilder buffer = new StringBuilder(); |
| if (!Field.Equals(field, StringComparison.Ordinal)) |
| { |
| buffer.Append(Field); |
| buffer.Append(":"); |
| } |
| buffer.Append(_prefix.Text()); |
| buffer.Append('*'); |
| buffer.Append(ToStringUtils.Boost(Boost)); |
| return buffer.ToString(); |
| } |
| |
| public override int GetHashCode() |
| { |
| const int prime = 31; |
| int result = base.GetHashCode(); |
| result = prime * result + ((_prefix == null) ? 0 : _prefix.GetHashCode()); |
| return result; |
| } |
| |
| public override bool Equals(object obj) |
| { |
| if (this == obj) |
| { |
| return true; |
| } |
| if (!base.Equals(obj)) |
| { |
| return false; |
| } |
| if (this.GetType() != obj.GetType()) |
| { |
| return false; |
| } |
| PrefixQuery other = (PrefixQuery)obj; |
| if (_prefix == null) |
| { |
| if (other._prefix != null) |
| { |
| return false; |
| } |
| } |
| else if (!_prefix.Equals(other._prefix)) |
| { |
| return false; |
| } |
| return true; |
| } |
| } |
| } |