1
package org.apache.lucene.facet.index.streaming;
3
import java.io.IOException;
4
import java.util.Iterator;
6
import org.apache.lucene.analysis.TokenStream;
8
import org.apache.lucene.facet.index.attributes.CategoryAttribute;
11
* Licensed to the Apache Software Foundation (ASF) under one or more
12
* contributor license agreements. See the NOTICE file distributed with
13
* this work for additional information regarding copyright ownership.
14
* The ASF licenses this file to You under the Apache License, Version 2.0
15
* (the "License"); you may not use this file except in compliance with
16
* the License. You may obtain a copy of the License at
18
* http://www.apache.org/licenses/LICENSE-2.0
20
* Unless required by applicable law or agreed to in writing, software
21
* distributed under the License is distributed on an "AS IS" BASIS,
22
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
23
* See the License for the specific language governing permissions and
24
* limitations under the License.
28
* An attribute stream built from an {@link Iterable} of
29
* {@link CategoryAttribute}. This stream should then be passed through several
30
* filters (see {@link CategoryParentsStream}, {@link CategoryListTokenizer} and
31
* {@link CategoryTokenizer}) until a token stream is produced that can be
34
* A CategoryAttributesStream object can be reused for producing more than one
35
* stream. To do that, the user should cause the underlying
36
* Iterable<CategoryAttribute> object to return a new set of categories, and
37
* then call {@link #reset()} to allow this stream to be used again.
39
* @lucene.experimental
41
public class CategoryAttributesStream extends TokenStream {
43
protected CategoryAttribute categoryAttribute;
45
private Iterable<CategoryAttribute> iterable;
46
private Iterator<CategoryAttribute> iterator;
52
* {@link Iterable} of {@link CategoryAttribute}, from which
53
* categories are taken.
55
public CategoryAttributesStream(Iterable<CategoryAttribute> iterable) {
56
this.iterable = iterable;
58
this.categoryAttribute = this.addAttribute(CategoryAttribute.class);
62
public final boolean incrementToken() throws IOException {
63
if (iterator == null) {
64
if (iterable == null) {
67
iterator = iterable.iterator();
69
if (iterator.hasNext()) {
70
categoryAttribute.set(iterator.next());