| /* |
| * 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. |
| */ |
| |
| /** |
| * Taxonomy of Categories. |
| * <p> |
| * Facets are defined using a hierarchy of categories, known as a <i>Taxonomy</i>. |
| * For example, the taxonomy of a book store application might have the following structure: |
| * |
| * <ul> |
| * <li>Author |
| * <ul> |
| * <li>Mark Twain</li> |
| * <li>J. K. Rowling</li> |
| * </ul> |
| * </li> |
| * </ul> |
| * |
| * <ul> |
| * <li>Date |
| * <ul> |
| * <li>2010</li> |
| * </ul> |
| * <ul> |
| * <li>March</li> |
| * <li>April</li> |
| * </ul> |
| * </li> |
| * <li>2009</li> |
| * </ul> |
| * |
| * <p> |
| * The <i>Taxonomy</i> translates category-paths into integer identifiers (often termed <i>ordinals</i>) and vice versa. |
| * The category <code>Author/Mark Twain</code> adds two nodes to the taxonomy: <code>Author</code> and |
| * <code>Author/Mark Twain</code>, each is assigned a different ordinal. The taxonomy maintains the invariant that a |
| * node always has an ordinal that is < all its children. |
| */ |
| package org.apache.lucene.facet.taxonomy; |
