| package org.apache.lucene.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. |
| */ |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.index.TermsEnum; |
| import org.apache.lucene.index.Term; |
| import org.apache.lucene.index.Terms; |
| import org.apache.lucene.util.AttributeSource; |
| import org.apache.lucene.util.ToStringUtils; |
| |
| /** A Query that matches documents containing terms with a specified prefix. A PrefixQuery |
| * is built by QueryParser for input like <code>app*</code>. |
| * |
| * <p>This query uses the {@link |
| * MultiTermQuery#CONSTANT_SCORE_AUTO_REWRITE_DEFAULT} |
| * rewrite method. */ |
| public class PrefixQuery extends MultiTermQuery { |
| private Term prefix; |
| |
| /** Constructs a query for terms starting with <code>prefix</code>. */ |
| public PrefixQuery(Term prefix) { |
| super(prefix.field()); |
| this.prefix = prefix; |
| } |
| |
| /** Returns the prefix of this query. */ |
| public Term getPrefix() { return prefix; } |
| |
| @Override |
| protected TermsEnum getTermsEnum(Terms terms, AttributeSource atts) throws IOException { |
| TermsEnum tenum = terms.iterator(null); |
| |
| if (prefix.bytes().length == 0) { |
| // no prefix -- match all terms for this field: |
| return tenum; |
| } |
| return new PrefixTermsEnum(tenum, prefix.bytes()); |
| } |
| |
| /** Prints a user-readable version of this query. */ |
| @Override |
| public String toString(String field) { |
| StringBuilder buffer = new StringBuilder(); |
| if (!getField().equals(field)) { |
| buffer.append(getField()); |
| buffer.append(":"); |
| } |
| buffer.append(prefix.text()); |
| buffer.append('*'); |
| buffer.append(ToStringUtils.boost(getBoost())); |
| return buffer.toString(); |
| } |
| |
| @Override |
| public int hashCode() { |
| final int prime = 31; |
| int result = super.hashCode(); |
| result = prime * result + ((prefix == null) ? 0 : prefix.hashCode()); |
| return result; |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) |
| return true; |
| if (!super.equals(obj)) |
| return false; |
| if (getClass() != obj.getClass()) |
| 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; |
| } |
| |
| } |