1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.math4.legacy.linear;
18
19 import org.apache.commons.math4.legacy.core.FieldElement;
20
21 /**
22 * This interface defines a visitor for the entries of a vector. Visitors
23 * implementing this interface may alter the entries of the vector being
24 * visited.
25 *
26 * @param <T> the type of the field elements
27 * @since 3.3
28 */
29 public interface FieldVectorChangingVisitor<T extends FieldElement<?>> {
30 /**
31 * Start visiting a vector. This method is called once, before any entry
32 * of the vector is visited.
33 *
34 * @param dimension the size of the vector
35 * @param start the index of the first entry to be visited
36 * @param end the index of the last entry to be visited (inclusive)
37 */
38 void start(int dimension, int start, int end);
39
40 /**
41 * Visit one entry of the vector.
42 *
43 * @param index the index of the entry being visited
44 * @param value the value of the entry being visited
45 * @return the new value of the entry being visited
46 */
47 T visit(int index, T value);
48
49 /**
50 * End visiting a vector. This method is called once, after all entries of
51 * the vector have been visited.
52 *
53 * @return the value returned after visiting all entries
54 */
55 T end();
56 }