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