| package org.apache.lucene.search; |
| |
| /* ==================================================================== |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 2001 The Apache Software Foundation. All rights |
| * reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, |
| * if any, must include the following acknowledgment: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowledgment may appear in the software itself, |
| * if and wherever such third-party acknowledgments normally appear. |
| * |
| * 4. The names "Apache" and "Apache Software Foundation" and |
| * "Apache Lucene" must not be used to endorse or promote products |
| * derived from this software without prior written permission. For |
| * written permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache", |
| * "Apache Lucene", nor may "Apache" appear in their name, without |
| * prior written permission of the Apache Software Foundation. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
| * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| |
| import java.io.IOException; |
| import org.apache.lucene.index.Term; |
| import org.apache.lucene.index.TermDocs; |
| import org.apache.lucene.index.IndexReader; |
| |
| /** A Query that matches documents containing a term. |
| This may be combined with other terms with a {@link BooleanQuery}. |
| */ |
| final public class TermQuery extends Query { |
| private Term term; |
| private float idf = 0.0f; |
| private float weight = 0.0f; |
| |
| /** Constructs a query for the term <code>t</code>. */ |
| public TermQuery(Term t) { |
| term = t; |
| } |
| |
| final float sumOfSquaredWeights(Searcher searcher) throws IOException { |
| idf = Similarity.idf(term, searcher); |
| weight = idf * boost; |
| return weight * weight; // square term weights |
| } |
| |
| final void normalize(float norm) { |
| weight *= norm; // normalize for query |
| weight *= idf; // factor from document |
| } |
| |
| Scorer scorer(IndexReader reader) |
| throws IOException { |
| TermDocs termDocs = reader.termDocs(term); |
| |
| if (termDocs == null) |
| return null; |
| |
| return new TermScorer(termDocs, reader.norms(term.field()), weight); |
| } |
| |
| /** Prints a user-readable version of this query. */ |
| public String toString(String field) { |
| StringBuffer buffer = new StringBuffer(); |
| if (!term.field().equals(field)) { |
| buffer.append(term.field()); |
| buffer.append(":"); |
| } |
| buffer.append(term.text()); |
| if (boost != 1.0f) { |
| buffer.append("^"); |
| buffer.append(Float.toString(boost)); |
| } |
| return buffer.toString(); |
| } |
| } |