| /* |
| * 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. |
| */ |
| |
| /** |
| * The calculus of spans. |
| * |
| * <p>A span is a <code><doc,startPosition,endPosition></code> tuple that is enumerated by |
| * class {@link org.apache.lucene.search.spans.Spans Spans}. |
| * </p> |
| * |
| * <p>The following span query operators are implemented: |
| * |
| * <ul> |
| * |
| * <li>A {@link org.apache.lucene.search.spans.SpanTermQuery SpanTermQuery} matches all spans |
| * containing a particular {@link org.apache.lucene.index.Term Term}. |
| * This should not be used for terms that are indexed at position Integer.MAX_VALUE. |
| * </li> |
| * |
| * <li> A {@link org.apache.lucene.search.spans.SpanNearQuery SpanNearQuery} matches spans |
| * which occur near one another, and can be used to implement things like |
| * phrase search (when constructed from {@link org.apache.lucene.search.spans.SpanTermQuery}s) |
| * and inter-phrase proximity (when constructed from other {@link org.apache.lucene.search.spans.SpanNearQuery}s).</li> |
| * |
| * <li> A {@link org.apache.lucene.search.spans.SpanWithinQuery SpanWithinQuery} matches spans |
| * which occur inside of another spans. </li> |
| * |
| * <li> A {@link org.apache.lucene.search.spans.SpanContainingQuery SpanContainingQuery} matches spans |
| * which contain another spans. </li> |
| * |
| * <li>A {@link org.apache.lucene.search.spans.SpanOrQuery SpanOrQuery} merges spans from a |
| * number of other {@link org.apache.lucene.search.spans.SpanQuery}s.</li> |
| * |
| * <li>A {@link org.apache.lucene.search.spans.SpanNotQuery SpanNotQuery} removes spans |
| * matching one {@link org.apache.lucene.search.spans.SpanQuery SpanQuery} which overlap (or comes |
| * near) another. This can be used, e.g., to implement within-paragraph |
| * search.</li> |
| * |
| * <li>A {@link org.apache.lucene.search.spans.SpanFirstQuery SpanFirstQuery} matches spans |
| * matching <code>q</code> whose end position is less than |
| * <code>n</code>. This can be used to constrain matches to the first |
| * part of the document.</li> |
| * |
| * <li>A {@link org.apache.lucene.search.spans.SpanPositionRangeQuery SpanPositionRangeQuery} is |
| * a more general form of SpanFirstQuery that can constrain matches to arbitrary portions of the document.</li> |
| * |
| * </ul> |
| * |
| * In all cases, output spans are minimally inclusive. In other words, a |
| * span formed by matching a span in x and y starts at the lesser of the |
| * two starts and ends at the greater of the two ends. |
| * |
| * <p>For example, a span query which matches "John Kerry" within ten |
| * words of "George Bush" within the first 100 words of the document |
| * could be constructed with: |
| * <pre class="prettyprint"> |
| * SpanQuery john = new SpanTermQuery(new Term("content", "john")); |
| * SpanQuery kerry = new SpanTermQuery(new Term("content", "kerry")); |
| * SpanQuery george = new SpanTermQuery(new Term("content", "george")); |
| * SpanQuery bush = new SpanTermQuery(new Term("content", "bush")); |
| * |
| * SpanQuery johnKerry = |
| * new SpanNearQuery(new SpanQuery[] {john, kerry}, 0, true); |
| * |
| * SpanQuery georgeBush = |
| * new SpanNearQuery(new SpanQuery[] {george, bush}, 0, true); |
| * |
| * SpanQuery johnKerryNearGeorgeBush = |
| * new SpanNearQuery(new SpanQuery[] {johnKerry, georgeBush}, 10, false); |
| * |
| * SpanQuery johnKerryNearGeorgeBushAtStart = |
| * new SpanFirstQuery(johnKerryNearGeorgeBush, 100); |
| * </pre> |
| * |
| * <p>Span queries may be freely intermixed with other Lucene queries. |
| * So, for example, the above query can be restricted to documents which |
| * also use the word "iraq" with: |
| * |
| * <pre class="prettyprint"> |
| * Query query = new BooleanQuery(); |
| * query.add(johnKerryNearGeorgeBushAtStart, true, false); |
| * query.add(new TermQuery("content", "iraq"), true, false); |
| * </pre> |
| */ |
| package org.apache.lucene.search.spans; |
